{"product_id":"less-surgery-for-breast-cancer-what-the-evidence-shows-about-breast-conserving-surgery-and-sentinel-node-biopsy","title":"Less Surgery for Breast Cancer: What the Evidence Shows About Breast-Conserving Surgery and Sentinel Node Biopsy","description":"\u003cp\u003eThis review article summarizes more than 20 landmark clinical trials that tested whether less extensive breast and lymph node surgery can safely treat breast cancer. The authors report that breast-conserving surgery (removing only the tumor plus a margin of normal tissue) produces survival rates equivalent to mastectomy (removal of the whole breast) in most patients. The authors also report that sentinel lymph node biopsy (removal of one to a few key lymph nodes) can often be omitted entirely in carefully selected patients with early-stage disease. Newer tools such as magnetic resonance imaging (MRI), genomic tumor testing, and blood tests for circulating tumor DNA may help doctors identify which patients can safely receive less surgery. However, the authors caution that most de-escalation evidence comes from selected patient groups, follow-up remains short in several trials, and global access to these approaches is uneven.\u003c\/p\u003e\n\n\u003ch1\u003eLess Surgery for Breast Cancer: What the Evidence Shows About Breast-Conserving Surgery and Sentinel Node Biopsy\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"#background\"\u003eBackground: How Breast Cancer Surgery Became Less Radical\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#bcs-vs-mastectomy\"\u003eLong-Term Outcomes: Breast-Conserving Surgery Versus Mastectomy\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#multicentric\"\u003eBreast-Conserving Surgery in Multicentric Disease\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#pcr\"\u003ePathologic Complete Response and the Idea of Skipping Surgery\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#micra-responder\"\u003eThe MICRA and RESPONDER Trials\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#future-selection\"\u003eFuture Directions in Patient Selection\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#axillary\"\u003eDe-Escalation of Axillary (Lymph Node) Surgery\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#omit-slnb\"\u003eOmitting Sentinel Lymph Node Biopsy in Node-Negative Patients\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#sound\"\u003eThe SOUND Trial: Ultrasound-Based Selection\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#insema\"\u003eThe INSEMA Trial\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#nautilus\"\u003eThe NAUTILUS Trial (Korea, 2020–2022)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#boog\"\u003eThe BOOG 13–08 Trial\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#liquid-biopsy\"\u003eFuture Directions: Liquid Biopsy and Artificial Intelligence\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#alnd\"\u003eOmitting Axillary Lymph Node Dissection in Sentinel Node-Positive Disease\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#z0011\"\u003eThe ACOSOG Z0011 Trial: A Paradigm Shift\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#clinical-implications\"\u003eClinical Implications: What This Means for Patients\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#limitations\"\u003eLimitations: What the Evidence Cannot Yet Prove\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIn most patients, breast-conserving surgery plus radiotherapy gives survival equivalent to mastectomy, confirmed by trials with 15 to 20 years of follow-up.\u003c\/li\u003e\n\u003cli\u003eSentinel lymph node biopsy can often be omitted in carefully selected early-stage patients; the SOUND, INSEMA and NAUTILUS trials found no difference in disease-free survival.\u003c\/li\u003e\n\u003cli\u003eOmitting sentinel node biopsy reduced arm swelling and mobility problems by roughly 22 to 30 percent in the SOUND and INSEMA trials.\u003c\/li\u003e\n\u003cli\u003eSkipping breast surgery entirely is not yet supported: biopsy missed residual disease in 37 percent of MICRA patients and NRG-BR005 sensitivity was only 50 percent.\u003c\/li\u003e\n\u003cli\u003eMost de-escalation evidence comes from selected groups, mainly postmenopausal hormone receptor-positive, HER2-negative, early-stage disease, and follow-up remains short in several trials.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eBackground: How Breast Cancer Surgery Became Less Radical\u003c\/h2\u003e\n\n\u003cp\u003eThe history of breast cancer surgery began with the most aggressive operation possible. William Halsted introduced the radical mastectomy (removal of the breast, chest muscles, and lymph nodes in one block). Doctors adopted this operation as the gold standard after it improved 5-year survival from 13% to 40%. More than 90% of patients received this operation until 1970.\u003c\/p\u003e\n\n\u003cp\u003eDespite such extensive surgery, the radical mastectomy carried severe side effects. Local recurrence (cancer returning in the same area) occurred in 6% of patients, and regional recurrence occurred in 22%. More than 50% of patients developed chronic lymphedema (long-term swelling of the arm caused by lymph fluid buildup). Many patients also experienced major chest wall deformities and shoulder dysfunction.\u003c\/p\u003e\n\n\u003cp\u003eSurgeons Patey and Madden later modified the operation to preserve the pectoralis major muscle (the large chest muscle). These modified operations reduced complications while maintaining the same cancer outcomes.\u003c\/p\u003e\n\n\u003cp\u003eA major change in thinking arrived in the 1980s. The researcher Fisher redefined breast cancer as a systemic disease (a disease that affects the whole body), not just a local problem in the breast. This new understanding reduced the need for aggressive local therapy in every patient.\u003c\/p\u003e\n\n\u003cp\u003eClinical evidence soon supported this shift. The NSABP B-18 trial showed that neoadjuvant chemotherapy (drug treatment given before surgery) shrank tumors in 80% of 1,523 patients with operable breast cancer. This shrinkage allowed 12% more patients to receive lumpectomy (removal of the tumor plus a margin of normal tissue) compared with patients who received chemotherapy after surgery. Complete remission occurred in 36% of patients. This landmark study proved for the first time that neoadjuvant chemotherapy could safely make breast-conserving surgery possible without compromising survival.\u003c\/p\u003e\n\n\u003cp\u003eThe NSABP B-27 trial followed in 2006 and changed neoadjuvant therapy again. Adding docetaxel (a chemotherapy drug) to AC chemotherapy (a combination of doxorubicin and cyclophosphamide) doubled the rate of pathologic complete response (pCR) in 2,411 patients with breast cancer. pCR means no cancer cells remained in the breast tissue when examined under a microscope, and the rate rose from 13% to 26%. The study confirmed a survival benefit for taxane drugs (disease-free survival hazard ratio 0.71) and established that achieving pCR predicted better long-term outcomes. This finding made taxane-based regimens the standard for shrinking tumors and increasing the number of patients eligible for breast-conserving surgery.\u003c\/p\u003e\n\n\u003ch2 id=\"bcs-vs-mastectomy\"\u003eLong-Term Outcomes: Breast-Conserving Surgery Versus Mastectomy\u003c\/h2\u003e\n\n\u003cp\u003eDecades of clinical trials consistently show equivalent survival outcomes between breast-conserving surgery (BCS) with radiotherapy and mastectomy. The Gustave-Roussy trial, with 15 years of follow-up, showed overall survival rates of 73% for BCS versus 65% for mastectomy.\u003c\/p\u003e\n\n\u003cp\u003eThe landmark NSABP B-06 and Milan trials, with 20 years of follow-up, confirmed this equivalence. Survival was 46–59% for BCS compared with 47–58% for mastectomy.\u003c\/p\u003e\n\n\u003cp\u003eEarly studies did show slightly higher local recurrence rates with BCS (9–14%) versus mastectomy (2–10%). However, these differences fell within acceptable oncologic thresholds (less than 5% at 5 years). Modern advances have dramatically improved outcomes. These advances include precision radiotherapy techniques and the adoption of \"no tumor on ink\" margin standards (meaning no cancer cells touch the edge of the removed tissue). With these techniques, BCS recurrence rates are now less than 2% in contemporary practice.\u003c\/p\u003e\n\n\u003cp\u003eThese long-term data show that when performed with current surgical and radiation techniques, BCS provides equivalent cancer control to mastectomy while preserving the breast.\u003c\/p\u003e\n\n\u003cp\u003eThe table below summarizes the key long-term trial results.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGustave-Roussy (1996), 15 years of follow-up:\u003c\/strong\u003e overall survival 73% with BCS plus radiotherapy versus 65% with mastectomy; local recurrence 13% with BCS versus 18% with mastectomy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNSABP B-06 (2002), 20 years of follow-up:\u003c\/strong\u003e overall survival 46% with BCS plus radiotherapy versus 47% with mastectomy; local recurrence 14% with BCS versus 10% with mastectomy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMilan (2002), 20 years of follow-up:\u003c\/strong\u003e overall survival 59% with BCS plus radiotherapy versus 58% with mastectomy; local recurrence 9% with BCS versus 2% with mastectomy.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"multicentric\"\u003eBreast-Conserving Surgery in Multicentric Disease\u003c\/h2\u003e\n\n\u003cp\u003eThe ACOSOG Z11102 trial challenged conventional wisdom by evaluating breast-conserving surgery in 198 patients with multiple tumors in the same breast. Most patients (96%) had two tumor foci, and the median tumor size was 1.5 cm.\u003c\/p\u003e\n\n\u003cp\u003eThe results were compelling. Surgeons achieved clear margins in a single operation for 67.5% of patients. Only 7.1% of patients required conversion to mastectomy. Most importantly, the 5-year local recurrence rate of 3.3% matched the outcomes seen in single-tumor cases. This finding demonstrated comparable oncologic safety.\u003c\/p\u003e\n\n\u003cp\u003eOne critical finding involved preoperative MRI (magnetic resonance imaging, a detailed scan done before surgery). Preoperative MRI dramatically reduced recurrence rates from 22.6% to just 1.7%. This reduction was statistically significant (hazard ratio 13.49, p=0.02). The finding highlights the essential role of MRI in selecting the right patients and planning surgery for multifocal disease (cancer in more than one area of the breast).\u003c\/p\u003e\n\n\u003cp\u003eThe 2020 follow-up analysis of the ACOSOG Z11102 trial provided valuable insights into patient-reported outcomes after BCS for multifocal disease. Using validated BREAST-Q measures (standardized questionnaires about quality of life and satisfaction), researchers found remarkable stability in patient satisfaction scores. Scores declined only slightly, from 76.3 points after surgery to 73 points at 3-year follow-up.\u003c\/p\u003e\n\n\u003cp\u003ePatients' sense of well-being improved substantially over time. Scores rose from 58 points immediately after surgery to 70–80 points by 5 years. This rise reflects meaningful recovery from the initial burden of treatment. On the standardized 4-point Winchester \u0026amp; Cox scale, 82% of patients rated their cosmetic results as \"good\" or \"excellent\" at the 3-year mark.\u003c\/p\u003e\n\n\u003cp\u003eThese outcomes proved comparable to those achieved with single-focus BCS in historic trials such as NSABP B-06, which reported 78% satisfaction at 5 years. This comparison confirms that multifocal BCS can successfully balance oncologic rigor with preservation of quality of life and body image. This balance is a crucial dual priority in contemporary breast cancer management.\u003c\/p\u003e\n\n\u003cp\u003eAcross retrospective and prospective cohort studies, BCS demonstrated comparable survival and recurrence outcomes to mastectomy in selected patients with multifocal or multicentric disease. When negative margins can be achieved and cosmetic outcomes maintained, breast conservation is a safe option.\u003c\/p\u003e\n\n\u003cp\u003eSeveral cohort studies support this conclusion. Nose and colleagues (1999) studied 56 patients who had BCS and 132 who had mastectomy and found no significant difference in recurrence or survival rates. Kaplan and colleagues (2003) studied 36 patients who had BCS and 19 who had mastectomy and found that the type of surgery had no impact on 5-year overall or disease-free survival. Oh and colleagues (2006) studied 20 patients who had BCS and 27 who had mastectomy and found no significant difference in disease-free or overall survival.\u003c\/p\u003e\n\n\u003cp\u003eGentilini and colleagues (2009) reported a local recurrence rate of 5.1% at 5 years in 476 patients who had BCS. Lynch and colleagues (2013) studied 1,757 patients with unifocal breast cancer and 1,059 patients with multifocal breast cancer and concluded that BCS is a safe option for multifocal breast cancer. Wolters and colleagues (2013) studied 256 patients with multifocal breast cancer who had BCS and 417 who had mastectomy. Wolters and colleagues also studied 623 patients with multifocal breast cancer who had BCS and 319 who had mastectomy. Wolters and colleagues also studied 60 patients with multicentric breast cancer who had BCS and 40 who had mastectomy. All patients with multicentric breast cancer in that cohort had a mastectomy, and the study found no significant difference in disease-free or overall survival. Winters and colleagues (2018) studied 3,537 patients with multifocal or multicentric breast cancer and found that BCS and mastectomy had similar loco-regional recurrence. The authors supported a future randomized trial.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Innovations\u003c\/h3\u003e\n\n\u003cp\u003eOncoplastic surgery combines cancer removal with plastic surgery techniques to reshape the breast. The \"extreme oncoplasty\" cohort included 86 patients with multifocal or multicentric disease and a median tumor span of about 65 mm. This group reported a local recurrence rate of 3.4% after about 75 months, with excellent cosmetic results in nearly half of patients.\u003c\/p\u003e\n\n\u003cp\u003eThe UK MIAMI trial is currently randomizing patients with multifocal or multicentric disease to therapeutic mammoplasty (a form of oncoplastic BCS) versus mastectomy. There is no evidence that the surgical approach affects prognosis, provided that tumors are completely excised.\u003c\/p\u003e\n\n\u003cp\u003eCurrent evidence points to breast conservation as safe for multifocal and multicentric breast cancer when the operation is technically feasible and acceptable cosmetic results can be achieved. Some patients may choose mastectomy over breast conservation. However, their choices should not be limited by a lack of surgical skill or local expertise in oncoplastic breast surgery.\u003c\/p\u003e\n\n\u003ch2 id=\"pcr\"\u003ePathologic Complete Response and the Idea of Skipping Surgery\u003c\/h2\u003e\n\n\u003cp\u003eIn a 2025 narrative review titled \"Omission of breast surgery in exceptional responders after neoadjuvant chemotherapy—what are future possibilities?\", Phang and Weiss examined whether surgery can safely be omitted. Phang and Weiss examined this in patients with early-stage triple-negative breast cancer (TNBC) or HER2-positive breast cancer (HER2+) who achieve a pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC).\u003c\/p\u003e\n\n\u003cp\u003eThe authors reviewed 49 studies published between 1989 and 2024. These studies included clinical trials, retrospective analyses, and review articles. Their analysis confirms that TNBC and HER2+ tumors often respond very well to systemic therapy. Reported breast pCR rates reach about 64% for TNBC and about 66% for HER2+ disease. However, reliably predicting pCR remains challenging.\u003c\/p\u003e\n\n\u003cp\u003eConventional physical examination and imaging (mammography, ultrasound, and MRI) prove insufficient. In many cases, these methods fail to detect residual disease accurately. Minimally invasive sampling methods, such as vacuum-assisted biopsy (VAB, a technique that removes tissue samples with a suction device), show more promise. When optimized with an adequate needle gauge and a sufficient number of cores, VAB has reported false-negative rates as low as about 2.9% in selected, well-sampled cases.\u003c\/p\u003e\n\n\u003cp\u003eDespite these encouraging findings, the authors emphasize that current surgery-omission trials are small, and their patient populations are highly selected. The authors also note a reluctance among many patients to skip surgery, even when skipping surgery is medically feasible. Completed evidence is therefore insufficient to recommend surgery omission broadly. This limitation includes multifocal and multicentric tumors, where data remain especially scarce.\u003c\/p\u003e\n\n\u003cp\u003eThe authors conclude that surgical de-escalation may become a valid option in the future. The most realistic form of de-escalation is avoidance of mastectomy rather than complete omission of surgery. Larger-scale studies with long-term follow-up are needed. The authors also urge that patient preferences and resource constraints be considered carefully.\u003c\/p\u003e\n\n\u003ch2 id=\"micra-responder\"\u003eThe MICRA and RESPONDER Trials\u003c\/h2\u003e\n\n\u003cp\u003eThe MICRA trial is a multicenter, prospective single-arm study conducted in three Dutch hospitals. The trial enrolled patients with T1–4 breast cancer (tumor stages 1 through 4) who had either no lymph node involvement or positive lymph nodes. All patients had either a radiologic partial response (rPR) with enhancement of 2.0 cm or less on MRI. Alternatively, all patients had a radiologic complete response (rCR) after neoadjuvant systemic therapy (NST, drug treatment given before surgery). rPR means the tumor shrank but did not disappear on imaging, and rCR means the tumor was no longer visible on imaging.\u003c\/p\u003e\n\n\u003cp\u003eBefore surgery, doctors took eight ultrasound-guided 14-G core biopsies (tissue samples taken with a hollow needle) in the operating room. The doctors took the biopsies close to the marker placed in the tumor area at diagnosis. Between April 2016 and June 2019, 202 patients met the eligibility criteria. Pre-surgical biopsies were obtained in 167 patients. Of these, 136 had rCR and 31 had rPR on MRI.\u003c\/p\u003e\n\n\u003cp\u003eTumor subtypes in the study were distributed as follows: 43 tumors (26%) were hormone receptor (HR)-positive and HER2-negative, 64 (38%) were HER2-positive, and 60 (36%) were triple-negative.\u003c\/p\u003e\n\n\u003cp\u003eEighty-nine patients had pCR (53%; 95% confidence interval 45–61%), and 78 had residual disease. Biopsies were false-negative in 29 of 78 patients (37%; 95% confidence interval 27–49%). The factor most strongly associated with false-negative biopsies was rCR (false-negative rate 47%; odds ratio 9.81, 95% confidence interval 1.72–55.89; p=0.01). A trend was observed for HR-negative tumors (false-negative rate 71% in HER2-positive tumors and 55% in triple-negative tumors; odds ratio 4.55, 95% confidence interval 0.95–21.73; p=0.058). A trend was also observed for smaller pathologic lesions (6 mm versus 15 mm; odds ratio 0.93, 95% confidence interval 0.87–1.00; p=0.051).\u003c\/p\u003e\n\n\u003cp\u003eThe MICRA trial showed that ultrasound-guided core biopsies are not accurate enough to identify breast pCR in patients with a good response on MRI after NST. Therefore, breast surgery cannot safely be omitted based on the results of core biopsies in these patients.\u003c\/p\u003e\n\n\u003cp\u003eThe RESPONDER trial (NCT02945579) is an ongoing, multicenter phase II investigation. The trial is designed to determine whether breast surgery can be omitted in patients with triple-negative or HER2-positive breast cancer. These patients demonstrate a pathologic complete response after neoadjuvant systemic therapy, including immunotherapy. To verify pCR, patients undergo image-guided vacuum-assisted core sampling of the tumor bed, with a minimum of 12 cores required to rule out residual disease.\u003c\/p\u003e\n\n\u003cp\u003ePatients with biopsy-confirmed pCR may proceed directly to whole-breast radiotherapy. Patients with persistent invasive or in situ carcinoma (cancer that has not spread beyond the milk ducts) continue with standard surgical management. The study also incorporates liquid-biopsy-based surveillance, including circulating tumor DNA (ctDNA, tumor DNA found in the bloodstream) and circulating tumor cell (CTC) analyses, alongside imaging follow-up and patient-reported outcomes.\u003c\/p\u003e\n\n\u003cp\u003eEarly results from the first 50 participants indicate that 62% had no remaining invasive or in situ cancer on post-neoadjuvant biopsy. None of these patients experienced ipsilateral breast recurrence (cancer returning in the same breast) at a median follow-up of 26 months. Biopsy procedures were well tolerated, with no significant complications reported. These preliminary observations suggest that, within a carefully selected group, omission of breast surgery may be feasible without compromising early oncologic safety. The observations also suggest that ctDNA monitoring may serve as an additional safeguard against early relapse. Longer-term follow-up will be essential to confirm sustained local control and to validate this strategy as a potential practice-changing approach for highly responsive disease subtypes.\u003c\/p\u003e\n\n\u003cp\u003eParallel efforts have highlighted the challenges of reliably confirming pCR using percutaneous biopsy (a biopsy through the skin) alone. The NRG-BR005 study evaluated the diagnostic performance of stereotactic tumor-bed sampling. Stereotactic tumor-bed sampling is a biopsy guided by three-dimensional imaging. The study included patients who achieved both clinical and radiologic complete or near-complete responses after neoadjuvant chemotherapy.\u003c\/p\u003e\n\n\u003cp\u003eEligibility required completion of neoadjuvant therapy and demonstration of clinical complete response (cCR) accompanied by stringent radiologic criteria. These criteria were: residual tumor bed of 1 cm or less without malignant calcifications on mammography, 2 cm or less on ultrasound, and no suspicious enhancement on MRI. Participants underwent clip-directed stereotactic biopsies before breast-conserving surgery.\u003c\/p\u003e\n\n\u003cp\u003eAmong 98 evaluable patients with clinical T1–3 disease across breast cancer subtypes, 36 harbored residual disease at surgery. Only 18 of these cases were detected by stereotactic biopsy. This yielded a sensitivity of 50% and a negative predictive value (NPV, the chance that a negative test truly means no disease) of 77.5%. These results fell short of the predefined 90% threshold required to support surgery omission. These findings underscore the limitations of current biopsy techniques for confidently excluding residual disease. The final peer-reviewed report of NRG-BR005 is pending.\u003c\/p\u003e\n\n\u003cp\u003eMeanwhile, the I-SPY2 platform continues to advance neoadjuvant drug development by integrating novel therapeutics earlier in treatment. This approach increases pCR rates and creates a stronger foundation for future trials exploring surgical de-escalation in triple-negative and HER2-positive breast cancer.\u003c\/p\u003e\n\n\u003ch2 id=\"future-selection\"\u003eFuture Directions in Patient Selection\u003c\/h2\u003e\n\n\u003cp\u003eThe future of patient selection for multifocal breast-conserving surgery is evolving with advances in genomic profiling, breast imaging, and more use of oncoplastic surgical techniques. Trials like NRG-BR008 are investigating whether genomic risk scores, based on each tumor's biological signature, can guide decisions between BCS and more extensive surgery. This approach builds on tools like Oncotype DX (a genomic test that estimates the risk of cancer recurrence) and focuses specifically on multifocal disease.\u003c\/p\u003e\n\n\u003cp\u003eResearchers aim to predict several things:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eWhether margins will be clear after surgery\u003c\/li\u003e\n\u003cli\u003eWhether occult lesions (hidden cancer areas) are present\u003c\/li\u003e\n\u003cli\u003eHow aggressive the tumor is across different foci\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eEarly findings suggest that genomic profiling may resolve current gray areas. This benefit may be greatest in intermediate-risk cases where MRI results are inconclusive. If validated, this strategy could reduce unnecessary mastectomies and enable safer, personalized breast conservation.\u003c\/p\u003e\n\n\u003ch2 id=\"axillary\"\u003eDe-Escalation of Axillary (Lymph Node) Surgery\u003c\/h2\u003e\n\n\u003cp\u003eDe-escalation of axillary surgery began with Giuliano's introduction of sentinel lymph node biopsy (SLNB). In this procedure, doctors remove the first one to a few lymph nodes that cancer would likely reach first. SLNB replaced axillary lymph node dissection (ALND, removal of many lymph nodes under the arm) for patients with clinically node-negative disease. cN0 means the lymph nodes do not feel or look abnormal. This change significantly reduced lymphedema rates from 25% to less than 5%.\u003c\/p\u003e\n\n\u003cp\u003eThe NSABP B-32 trial confirmed that SLNB was not inferior to ALND. The trial showed comparable 10-year overall survival (87% with SLNB versus 89% with ALND).\u003c\/p\u003e\n\n\u003cp\u003eModern strategies for de-escalation are driven by three factors. First, systemic therapies are effective at managing micrometastatic disease (tiny amounts of cancer spread). Second, preoperative imaging has advanced. Third, doctors now focus on patient-reported outcomes such as lymphedema and quality of life.\u003c\/p\u003e\n\n\u003cp\u003eHowever, real-world adoption remains variable. Reasons include surgeon preferences, institutional practices, and access to genomic tools.\u003c\/p\u003e\n\n\u003ch2 id=\"omit-slnb\"\u003eOmitting Sentinel Lymph Node Biopsy in Node-Negative Patients\u003c\/h2\u003e\n\n\u003ch3 id=\"sound\"\u003eThe SOUND Trial: Ultrasound-Based Selection\u003c\/h3\u003e\n\n\u003cp\u003eThe SOUND trial (Gentilini et al., 2021) randomized 1,560 patients with T1 tumors (2 cm or smaller) and ultrasound-confirmed node-negative disease to either SLNB or no SLNB. At 5 years, there was no difference in disease-free survival (98.7% versus 98.0%) or axillary recurrence (0.5% versus 0.4%). Lymphedema was 22% lower in the omission group.\u003c\/p\u003e\n\n\u003cp\u003eA key limitation is the reliance on axillary ultrasound, which has a false-negative rate of about 25% in unselected patients. Additionally, the trial excluded lobular carcinoma (a cancer that starts in the milk-producing glands) and multifocal disease, which limits how broadly the results apply.\u003c\/p\u003e\n\n\u003cp\u003eThe clinical impact of the SOUND trial is that SLNB omission is now validated in ultra-low-risk T1N0 patients (small tumors with no lymph node involvement) who undergo rigorous imaging.\u003c\/p\u003e\n\n\u003ch3 id=\"insema\"\u003eThe INSEMA Trial\u003c\/h3\u003e\n\n\u003cp\u003eThe INSEMA trial is the largest randomized study of its kind, with 5,940 participants. The trial used an innovative two-phase design to evaluate axillary de-escalation in patients with tumors up to 5 cm. The study first randomized women to either SLNB or observation. The study then further randomized patients with a positive SLNB to either ALND or no further surgery. The trial produced practice-changing results.\u003c\/p\u003e\n\n\u003cp\u003eThe key findings were as follows:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEquivalent oncologic outcomes:\u003c\/strong\u003e 5-year disease-free survival showed no significant difference between groups (hazard ratio 0.94, p=0.62). This result challenged the necessity of routine SLNB.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSuperior patient experience:\u003c\/strong\u003e omitting SLNB resulted in a remarkable 30% reduction in arm morbidity, including lymphedema and mobility restrictions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBroad clinical applicability:\u003c\/strong\u003e by including both T1 and T2 tumors (up to 5 cm), the findings extend to a wider patient population than previous studies.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThis landmark trial provides the strongest evidence to date that many patients with early-stage breast cancer can safely avoid axillary surgery when systemic therapy is planned. These patients significantly reduce treatment-related complications without compromising cancer outcomes. The results particularly support omitting SLNB in hormone receptor-positive, HER2-negative cases. In these cases, adjuvant therapy decisions are primarily driven by tumor biology rather than nodal status.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePractice change:\u003c\/strong\u003e The evidence supports considering SLNB omission in well-imaged, low-risk (often HR-positive\/HER2-negative) T1–T2 tumors (5 cm or smaller) when adjuvant systemic therapy is already planned. However, decisions should account for operator variability in axillary ultrasound, limited long-term follow-up, potential impact on systemic therapy selection, and nodal-status-based eligibility for adjuvant CDK4\/6 inhibitors (such as monarchE).\u003c\/p\u003e\n\n\u003ch3 id=\"nautilus\"\u003eThe NAUTILUS Trial (Korea, 2020–2022)\u003c\/h3\u003e\n\n\u003cp\u003eThis groundbreaking prospective study specifically evaluated axillary management strategies in 1,734 Asian patients with breast cancer and tumors up to 5 cm. All patients received standardized adjuvant systemic therapy and whole-breast radiotherapy. The trial's design addressed an important gap in existing evidence. Asian populations typically show different tumor biology compared with Western cohorts studied in previous trials, including a higher prevalence of HER2-positive subtypes.\u003c\/p\u003e\n\n\u003cp\u003eThe results provided compelling evidence for practice change:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExcellent disease control:\u003c\/strong\u003e 3-year invasive disease-free survival was nearly identical between groups (97.1% without SLNB versus 96.8% with SLNB).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMinimal axillary recurrence:\u003c\/strong\u003e both groups maintained exceptionally low axillary recurrence rates of 0.3%.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBiological consistency:\u003c\/strong\u003e outcomes remained stable across different molecular subtypes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eNAUTILUS is the first major trial to confirm the safety of SLNB omission in Asian patients, so the trial carries particular significance for global practice guidelines. The findings demonstrate that genomic risk, rather than ethnicity, should drive axillary management decisions. The findings support the feasibility of omitting SLNB in carefully selected patients regardless of racial background when modern systemic therapies are used. This trial importantly expands the applicability of axillary de-escalation strategies to more diverse patient populations worldwide.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCaveats and generalizability.\u003c\/strong\u003e Although contemporary randomized data suggest that omission of axillary staging can be safe in carefully selected early-stage patients, the evidence base predominantly reflects HR-positive\/HER2-negative, postmenopausal, early-stage populations. In most studies, axillary assessment depended on clinical examination and axillary ultrasound. Both methods are operator- and institution-dependent, which introduces variability in staging accuracy. Follow-up remains relatively short in several trials. How omission of axillary staging influenced adjuvant systemic therapy selection is also insufficiently detailed.\u003c\/p\u003e\n\n\u003cp\u003eThese issues are increasingly relevant given the emerging adjuvant use of CDK4\/6 inhibitors. Eligibility for these drugs, as in the monarchE trial, depends on nodal status (4 or more positive nodes, or high-risk 1–3 positive nodes). Routine omission of SLNB may therefore risk under-staging patients who could qualify for escalated adjuvant therapy.\u003c\/p\u003e\n\n\u003cp\u003eRecent systemic therapy trials such as RxPONDER (Kalinsky et al., NEJM 2021) and TAILORx demonstrated that adjuvant chemotherapy decisions in HR-positive\/HER2-negative disease are increasingly guided by genomic assays. These decisions are increasingly guided by genomic assays rather than nodal status. This finding reinforces the argument that axillary staging may become redundant in many cases, because systemic treatment allocation is uncoupled from axillary findings. However, this finding also underscores the danger of under-staging patients who might qualify for escalated regimens such as adjuvant CDK4\/6 inhibitors (monarchE) or novel immunotherapy combinations.\u003c\/p\u003e\n\n\u003ch3 id=\"boog\"\u003eThe BOOG 13–08 Trial\u003c\/h3\u003e\n\n\u003cp\u003eThe BOOG 13–08 trial was a prospective, randomized, phase III study. The trial investigated the safety of omitting axillary lymph node dissection in clinically node-negative patients with breast cancer. These patients were found to have 1–3 positive sentinel lymph nodes after neoadjuvant systemic therapy.\u003c\/p\u003e\n\n\u003cp\u003eThe Dutch BOOG 13–08 study has the longest planned follow-up (10 years). The study specifically examines regional recurrence patterns in patients with T1–2N0 disease undergoing breast-conserving surgery with whole-breast radiotherapy. This rigorous design addresses a crucial evidence gap regarding the durability of omitting SLNB in early-stage patients.\u003c\/p\u003e\n\n\u003cp\u003eEarly results at 5 years demonstrate no significant difference in overall survival (86.3% versus 83.6%) or axillary recurrence.\u003c\/p\u003e\n\n\u003ch3 id=\"liquid-biopsy\"\u003eFuture Directions: Liquid Biopsy and Artificial Intelligence Risk Stratification\u003c\/h3\u003e\n\n\u003cp\u003eEmerging technologies may further refine patient selection and identify ultra-low-risk groups where SLNB can safely be omitted. These technologies include circulating tumor DNA (ctDNA) testing and machine learning models, such as Memorial Sloan Kettering's nomogram (a prediction tool that combines several patient factors).\u003c\/p\u003e\n\n\u003ch2 id=\"alnd\"\u003eOmitting Axillary Lymph Node Dissection in Sentinel Node-Positive Disease\u003c\/h2\u003e\n\n\u003ch3 id=\"z0011\"\u003eThe ACOSOG Z0011 Trial: A Paradigm Shift\u003c\/h3\u003e\n\n\u003cp\u003eThe ACOSOG Z0011 trial (Giuliano et al., 2011, 2017) was a landmark study that challenged the necessity of ALND in patients with 1–2 positive sentinel lymph nodes. The trial enrolled women with T1–2 tumors and clinically node-negative disease undergoing breast-conserving therapy with whole-breast radiotherapy.\u003c\/p\u003e\n\n\u003cp\u003eAt 10 years, there was no significant difference in overall survival (86.3% versus 83.6%) or axillary recurrence.\u003c\/p\u003e\n\n\u003ch2 id=\"clinical-implications\"\u003eClinical Implications: What This Means for Patients\u003c\/h2\u003e\n\n\u003cp\u003eThe evidence summarized in this review has direct meaning for patients facing breast cancer surgery. The most important message is that less surgery often produces the same cancer outcomes as more surgery, while reducing side effects.\u003c\/p\u003e\n\n\u003cp\u003eFor the breast itself, breast-conserving surgery followed by radiotherapy provides survival equivalent to mastectomy in most patients. This equivalence holds even for some patients with multiple tumor areas in the same breast, provided that clear margins can be achieved and cosmetic results are acceptable.\u003c\/p\u003e\n\n\u003cp\u003eFor the lymph nodes under the arm, sentinel lymph node biopsy can often be omitted entirely in carefully selected patients with early-stage disease. The SOUND, INSEMA, and NAUTILUS trials all support this approach. Omitting SLNB reduces arm swelling and mobility problems by roughly 22–30%.\u003c\/p\u003e\n\n\u003cp\u003ePatients should understand that these options depend on several factors. These factors include tumor size, tumor biology, imaging results, and whether systemic therapy is planned. Patients should also understand that most de-escalation evidence comes from specific groups, mainly postmenopausal patients with hormone receptor-positive, HER2-negative, early-stage disease.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eLimitations: What the Evidence Cannot Yet Prove\u003c\/h2\u003e\n\n\u003cp\u003eThe authors identify several important limitations in the current evidence. First, most de-escalation trials enrolled highly selected patients. The results may not apply to all patients with breast cancer.\u003c\/p\u003e\n\n\u003cp\u003eSecond, follow-up remains relatively short in several trials. The BOOG 13–08 trial has the longest planned follow-up at 10 years, but many other trials report only 3- to 5-year results.\u003c\/p\u003e\n\n\u003cp\u003eThird, axillary assessment in most studies depended on clinical examination and axillary ultrasound. Both methods vary between operators and institutions, which introduces variability in staging accuracy.\u003c\/p\u003e\n\n\u003cp\u003eFourth, how omitting axillary staging influences the choice of adjuvant systemic therapy is not sufficiently detailed. This gap matters because eligibility for certain drugs, such as adjuvant CDK4\/6 inhibitors, depends on nodal status.\u003c\/p\u003e\n\n\u003cp\u003eFifth, data on surgery omission (skipping breast surgery entirely) remain scarce, especially for multifocal and multicentric tumors. Biopsy techniques cannot yet reliably confirm that no cancer remains. The MICRA trial showed false-negative biopsy rates of 37%, and the NRG-BR005 study showed a sensitivity of only 50%.\u003c\/p\u003e\n\n\u003cp\u003eFinally, the authors highlight global disparities in adopting de-escalation strategies. Access to oncoplastic surgical expertise, advanced imaging, and genomic tools varies widely around the world.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients\u003c\/h2\u003e\n\n\u003cp\u003eBased on this review, patients with breast cancer can consider the following steps when discussing surgery with their care team.\u003c\/p\u003e\n\n\u003col\u003e\n\u003cli\u003eAsk whether breast-conserving surgery is an option for your tumor size, location, and number of tumor areas. For many patients, survival after breast-conserving surgery plus radiotherapy equals survival after mastectomy.\u003c\/li\u003e\n\u003cli\u003eAsk whether sentinel lymph node biopsy can be safely omitted. This option may be appropriate for small, well-imaged, node-negative tumors when systemic therapy is already planned.\u003c\/li\u003e\n\u003cli\u003eAsk whether preoperative MRI is needed. In the ACOSOG Z11102 trial, preoperative MRI reduced recurrence rates from 22.6% to 1.7% in patients with multiple tumor areas.\u003c\/li\u003e\n\u003cli\u003eAsk whether genomic testing of your tumor can guide treatment decisions. Genomic assays increasingly guide chemotherapy decisions instead of lymph node status.\u003c\/li\u003e\n\u003cli\u003eDiscuss the risk of lymphedema with your surgeon. Omitting sentinel lymph node biopsy reduced arm morbidity by 22–30% in the SOUND and INSEMA trials.\u003c\/li\u003e\n\u003cli\u003eAsk about your eligibility for clinical trials. Ongoing studies such as RESPONDER and NRG-BR008 are testing whether surgery can be reduced or omitted even further.\u003c\/li\u003e\n\u003cli\u003eUnderstand that de-escalation is not appropriate for every patient. Decisions should account for tumor biology, imaging results, planned systemic therapy, and institutional expertise.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eCan I have breast-conserving surgery instead of a mastectomy?\u003c\/h3\u003e\n\u003cp\u003eIn most patients, breast-conserving surgery plus radiotherapy gives survival equivalent to mastectomy. Trials with 15 to 20 years of follow-up, including Gustave-Roussy, NSABP B-06 and Milan, confirmed this. It may also be possible for some patients with multiple tumour areas in one breast, if clear margins can be achieved and cosmetic results are acceptable. Ask your team whether it is an option for your tumour size, location and number of tumour areas.\u003c\/p\u003e\n\u003ch3\u003eCan sentinel lymph node biopsy be safely skipped?\u003c\/h3\u003e\n\u003cp\u003eIn carefully selected patients with early-stage disease it often can. The SOUND, INSEMA and NAUTILUS trials found no difference in disease-free survival or axillary recurrence when sentinel node biopsy was omitted, and arm swelling and mobility problems fell by roughly 22 to 30 percent. This option may suit small, well-imaged, node-negative tumours when systemic therapy is already planned. Ask your team whether it applies to you.\u003c\/p\u003e\n\u003ch3\u003eWhat does it mean if I have a pathologic complete response?\u003c\/h3\u003e\n\u003cp\u003eA pathologic complete response means no cancer cells remain in the breast tissue when examined under a microscope after drug treatment given before surgery. Reported rates reach about 64 percent in triple-negative and about 66 percent in HER2-positive disease. It predicts better long-term outcomes, but it does not yet mean surgery can be skipped. Biopsy techniques cannot reliably confirm it, so surgery is still recommended.\u003c\/p\u003e\n\u003ch3\u003eCan I skip breast surgery altogether if my tumour responds well to chemotherapy?\u003c\/h3\u003e\n\u003cp\u003eNot based on current evidence. The MICRA trial found ultrasound-guided core biopsies missed residual disease in 37 percent of patients, and the NRG-BR005 study reported sensitivity of only 50 percent, below the 90 percent threshold needed. Surgery-omission trials are small and their patients highly selected. The most realistic form of de-escalation today is avoiding mastectomy rather than omitting surgery entirely. Larger studies with longer follow-up are needed.\u003c\/p\u003e\n\u003ch3\u003eWhat is the risk of arm swelling (lymphedema) after lymph node surgery?\u003c\/h3\u003e\n\u003cp\u003eRemoving many lymph nodes under the arm once caused lymphedema in about 25 percent of patients; sentinel lymph node biopsy, which removes only the first one to a few nodes, lowered this to less than 5 percent. In the SOUND and INSEMA trials, omitting sentinel node biopsy reduced arm morbidity, including swelling and mobility restrictions, by roughly 22 to 30 percent. Discuss your own risk with your surgeon.\u003c\/p\u003e\n\u003ch3\u003eWhy might my doctor recommend an MRI before surgery?\u003c\/h3\u003e\n\u003cp\u003eIn the ACOSOG Z11102 trial of 198 patients with multiple tumour areas in one breast, preoperative MRI reduced recurrence rates from 22.6 percent to 1.7 percent, a statistically significant difference. MRI helps select the right patients and plan surgery for multifocal disease. Ask your team whether a preoperative scan is needed in your case and how it would change the surgical plan.\u003c\/p\u003e\n\u003ch3\u003eDoes less surgery mean my cancer is more likely to come back?\u003c\/h3\u003e\n\u003cp\u003eIn the trials reviewed, no. Breast-conserving surgery with radiotherapy gave survival equivalent to mastectomy, and with modern radiotherapy and 'no tumour on ink' margin standards, recurrence rates are now under 2 percent in contemporary practice. However, most de-escalation evidence comes from selected groups, mainly postmenopausal patients with hormone receptor-positive, HER2-negative, early-stage disease, and follow-up is short in several trials.\u003c\/p\u003e\n\u003ch3\u003eIf I have early-stage breast cancer and my surgeon recommends a mastectomy or sentinel lymph node biopsy, when should I get a second opinion?\u003c\/h3\u003e\n\u003cp\u003eSeek a second opinion when breast-conserving surgery has not been offered for a tumor that may be suitable, when sentinel lymph node biopsy is planned without discussion of omitting it, or when multiple tumor areas are present and mastectomy is advised without preoperative MRI or oncoplastic expertise. Survival after breast-conserving surgery plus radiotherapy equals mastectomy in most patients, and sentinel node biopsy can often be omitted in selected early-stage disease, reducing arm morbidity by 22–30%. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e De-escalating breast and axillary surgery in breast cancer: evidence, controversies, and future directions.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Sharaf B, Seif A, Alawneh F, Bani Hani H, Sh Abrahim M, Jehad S, Abdallah M, Mahafdah S.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthor affiliations:\u003c\/strong\u003e Department of Medicine, King Hussein Cancer Center, Amman, Jordan; Department of Surgery, King Hussein Cancer Center, Amman, Jordan; School of Medicine, Yarmouk University, Irbid, Jordan; Department of Surgery, Jordanian Royal Medical Services, Amman, Jordan\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e Frontiers in Oncology, volume 16, article 1717340\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication details:\u003c\/strong\u003e Received 01 October 2025; revised 29 November 2025; accepted 02 February 2026; published 24 February 2026\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDOI:\u003c\/strong\u003e 10.3389\/fonc.2026.1717340\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eArticle type:\u003c\/strong\u003e Review\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eThis patient-friendly article is based on peer-reviewed research.\u003c\/em\u003e\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47828012531868,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/products\/less-surgery-for-breast-cancer-what-the-evidence-shows-about-breast-conserving-surgery-and-sentinel-node-biopsy","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}