{"product_id":"pregnancy-cancer-and-radiation-a-modern-guide-for-patients","title":"Pregnancy, Cancer, and Radiation: A Modern Guide for Patients","description":"\u003cp\u003eCancer affects about 1 in 1,000 pregnancies, and thousands of pregnant patients in the United States may need radiation procedures for diagnosis or treatment each year. A team of physicians, medical physicists, a patient advocate, and a lawyer reviewed existing guidelines and recent literature to create practical guidance on using radiation safely during pregnancy. The authors conclude that radiation can be delivered safely and effectively to pregnant patients in many circumstances. Decisions should be made through shared decision-making between the physician and the patient.\u003c\/p\u003e\n\n\u003ch1\u003ePregnancy, Cancer, and Radiation: A Modern Guide for Patients\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\"\u003eWhy This Guide Matters\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#how-made\"\u003eHow This Guide Was Created\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#dose-risk\"\u003eRadiation Dose and Fetal Risk\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#screening\"\u003ePregnancy Screening Before Treatment\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#imaging\"\u003eImaging During Pregnancy: Benefits and Risks\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#doses-imaging\"\u003eTypical Fetal Doses from Imaging Exams\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#radiation-therapy\"\u003eRadiation Therapy During Pregnancy\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#disease-sites\"\u003eCancer Types and Radiation Treatment\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ebrt\"\u003eExternal Beam Radiation Therapy and Fetal Dose\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#implications\"\u003eWhat This Means for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eLimitations and Gaps in Knowledge\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients and Providers\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\u003eRadiation can be delivered safely and effectively to pregnant patients in many circumstances, with decisions made through shared decision-making between physician and patient.\u003c\/li\u003e\n\u003cli\u003eFor many cancers outside the pelvis, fetal doses can be kept below 100 mGy, where deterministic effects are not relevant and stochastic risk is negligible or non-existent.\u003c\/li\u003e\n\u003cli\u003eDelaying or avoiding standard cancer treatment can significantly harm the pregnant patient's health; for cervical cancer, delays of 4 months or longer are associated with a 2.31 times increased risk of death.\u003c\/li\u003e\n\u003cli\u003ePregnancy screening before radiation therapy is recommended: a negative test within 14 days before external beam radiotherapy or 72 hours before therapeutic I-131.\u003c\/li\u003e\n\u003cli\u003ePencil beam scanning proton therapy can produce fetal doses over ten times lower than photon therapy for brain and head and neck cancers; passive scattering proton therapy is not recommended.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eWhy This Guide Matters\u003c\/h2\u003e\n\n\u003cp\u003eCancer occurs in approximately 1 in 1,000 pregnancies. This rate is rising, likely because more people are delaying childbearing and because detection has improved. The most common cancers during pregnancy include melanoma (a serious type of skin cancer), breast cancer, cervical cancer, lymphomas (cancers of the immune system), and leukemias (cancers of blood-forming cells).\u003c\/p\u003e\n\n\u003cp\u003ePregnancy itself is not a risk factor for cancer. However, diagnosis may be delayed when symptoms are mistakenly attributed to pregnancy. Managing cancer during pregnancy requires a team-based, patient-centered approach.\u003c\/p\u003e\n\n\u003cp\u003eThe American Society of Clinical Oncology (ASCO) provides a framework for handling the medical, legal, and ethical challenges of cancer care during pregnancy. ASCO recommends standard-of-care treatment when possible. When considering a deviation from standard treatment, the risks to both the patient and the fetus should be weighed carefully.\u003c\/p\u003e\n\n\u003cp\u003ePatients and physicians are often uncomfortable with fetal exposure to radiation or chemotherapy. However, deviating from standard treatments can significantly harm the pregnant patient's health. For example, treatment delays of 4 months or longer in cervical cancer are associated with a 2.31 times increased risk of death.\u003c\/p\u003e\n\n\u003cp\u003eIn most cases, pregnancy itself will not worsen prognosis unless the patient declines treatment because of concerns about the fetus. Unless medically necessary for the pregnant patient's health, the American College of Obstetricians and Gynecologists and ASCO recommend avoiding delivery before 37 weeks. This highlights how important it is to put fetal risk from cancer treatment into context, and to understand how any deviation from standard care affects both maternal and fetal health.\u003c\/p\u003e\n\n\u003cp\u003eWhile there are many resources for understanding surgery, systemic therapies, and other non-radiation treatments during pregnancy, guidance for radiotherapy is sparse and scattered. Radiotherapy is a cornerstone of cancer treatment and is beneficial in about 50% of cancer cases. In many cases, radiotherapy can be delivered with very low doses to the fetus.\u003c\/p\u003e\n\n\u003cp\u003eThe goal of this paper is to discuss how radiation can be safely considered for certain pregnant patients. This includes the vital importance of diagnostic imaging for proper staging, and the best practices for delivering treatment using modern approaches that minimize fetal risk. The paper also discusses patient-centered care and access issues.\u003c\/p\u003e\n\n\u003ch2 id=\"how-made\"\u003eHow This Guide Was Created\u003c\/h2\u003e\n\n\u003cp\u003eA team of physicians and medical physicists with expertise in imaging, radiotherapy, and maternal-fetal medicine was assembled. A patient advocate and a lawyer also joined the team.\u003c\/p\u003e\n\n\u003cp\u003eThe authors reviewed existing guidelines and recent literature. Where published guidance was lacking, the authors drew from their own experience. The resulting document discusses best practices for using radiation to treat cancer, as well as patient-centered care management and legal considerations.\u003c\/p\u003e\n\n\u003cp\u003eThe authors use terms like \"pregnant individuals\" and \"patients\" to acknowledge that not all pregnant people identify as women.\u003c\/p\u003e\n\n\u003ch2 id=\"dose-risk\"\u003eRadiation Dose and Fetal Risk\u003c\/h2\u003e\n\n\u003cp\u003eFetal risk from radiation depends on two main factors: the gestational age at the time of exposure and the radiation dose. Effects vary based on gestational age and the stage of organ development at the time of exposure.\u003c\/p\u003e\n\n\u003cp\u003eBefore 10 weeks from the last menstrual period, radiation can cause spontaneous abortion (miscarriage), growth restriction, congenital anomalies (birth defects), and anatomic malformations. These effects occur at thresholds of 200 mGy or more.\u003c\/p\u003e\n\n\u003cp\u003eAfter 10 weeks, the organs have been formed and are essentially immutable (unchangeable). Starting at 11 weeks, fetal risks include seizure, growth restriction, spontaneous abortion, and intellectual deficits of varying degrees. These risks occur at a range of dose thresholds from 100 to 2,000 mGy.\u003c\/p\u003e\n\n\u003cp\u003eRadiation effects fall into two categories. Deterministic effects occur above a threshold dose. Stochastic effects may occur at any dose, and the probability of occurrence typically increases with dose. Stochastic effects include radiation-induced cancer. However, the limited data suggest that cancer risk from radiation exposure during pregnancy is significantly lower than from exposure during early childhood.\u003c\/p\u003e\n\n\u003cp\u003eA fetal dose of 10-20 mGy may increase the risk of leukemia by a factor of 1.5 to 2.0 over a background rate of about 1 in 3,000. Restated, there is a greater than 99% chance that a fetus exposed to 20 mGy will be unaffected. At 50 mGy, there is about a 98% chance the fetus will be unaffected. However, uncertainties in estimates below 100 mGy prevent accurate risk quantification.\u003c\/p\u003e\n\n\u003cp\u003eGiven that fetal doses are typically well below 100 mGy, deterministic radiation effects are not relevant. Stochastic risk is negligible or non-existent at these low doses. External shielding of the fetus for x-ray-based imaging is no longer recommended. Shielding minimally reduces dose but may interfere with dose optimization tools or degrade image quality.\u003c\/p\u003e\n\n\u003ch2 id=\"screening\"\u003ePregnancy Screening Before Treatment\u003c\/h2\u003e\n\n\u003cp\u003eScreening for pregnancy before imaging is recommended prior to radiation therapy. Each practice should develop a standardized policy.\u003c\/p\u003e\n\n\u003cp\u003eScreening should focus on the patient's physical and endocrinologic capacity for childbearing and participation in behaviors that can result in pregnancy.\u003c\/p\u003e\n\n\u003cp\u003eFor external beam radiotherapy (EBRT), a negative pregnancy test should be secured within 14 days prior to treatment initiation. For therapeutic I-131 administration, a negative serum pregnancy test should be obtained 72 hours prior to treatment.\u003c\/p\u003e\n\n\u003cp\u003eUrine pregnancy tests can be used, but serum (blood) pregnancy tests can detect pregnancy earlier and with higher sensitivity. Knowledge of state regulations is helpful for pregnancy testing in minors, as the definition of minor and the requirement for parental consent varies by state.\u003c\/p\u003e\n\n\u003cp\u003eIt is important to counsel patients to prevent pregnancy during treatment and after radiopharmaceutical administration. Some radiopharmaceuticals are excreted in breastmilk. Generally, breastfeeding should cease for all I-131 labeled radiopharmaceuticals, Ga-67 citrate, and therapeutic administrations. Recommendations regarding the duration of interruption or cessation of breastfeeding after radiopharmaceuticals vary. An Authorized User or Nuclear Medicine Physician should be consulted.\u003c\/p\u003e\n\n\u003ch2 id=\"imaging\"\u003eImaging During Pregnancy: Benefits and Risks\u003c\/h2\u003e\n\n\u003cp\u003eImaging is critical in cancer screening, diagnosis, staging, and monitoring of treatment response. Clinicians should carefully consider imaging modalities that may impact the patient's course of treatment, in the context of fetal risk from ionizing radiation.\u003c\/p\u003e\n\n\u003cp\u003eDose optimization in imaging pregnant patients should include the same approaches used in non-pregnant patients. These approaches include proper x-ray field collimation (narrowing the beam to the area of interest). They also include correct patient positioning. They include limiting the number of views and phases to those necessary. They include only performing exams that will impact the course of care.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMammography:\u003c\/strong\u003e Pregnant patients should follow breast cancer screening guidelines for the general population. While the physical changes of pregnancy and lactation may degrade the diagnostic quality of mammography, this does not warrant a screening delay. Screening mammography is essential in detecting breast cancers that are not yet detectable by physical examination during pregnancy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eUltrasound:\u003c\/strong\u003e Ultrasound has 100% sensitivity in patients with a palpable breast mass. Specificity may be reduced, because breast cancer in pregnant patients is more likely to mimic benign (non-cancerous) lesions on ultrasound than in non-pregnant patients. Any solid mass identified on ultrasound should proceed to biopsy.\u003c\/p\u003e\n\n\u003cp\u003eContrast-enhanced ultrasound (CEUS) is useful for assessing tumors and lymph nodes with metastatic infiltration and for imaging patients receiving cardiotoxic chemotherapy regimens. Limited studies have shown that microbubbles in ultrasound contrast agents do not cross the placental barrier, and no adverse reactions have been observed. Despite no known risks, the American College of Radiology (ACR) only recommends CEUS use when there is a clear patient benefit.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMRI:\u003c\/strong\u003e Non-contrast MRI is considered safe during pregnancy when the static magnetic field is 3T or less and the scanner is in normal operating mode (whole body-averaged specific absorption ratio limited to 2 W\/kg). Evidence of fetal risk from gadolinium-based contrast agents (GBCA) is limited. Despite this, current recommendations discourage their use. Use is discouraged except when the anticipated clinical benefit justifies the unknown risk of fetal exposure to GBCA.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eX-ray:\u003c\/strong\u003e Planar radiography (standard x-ray) can be safely performed without modifications, given that fetal doses are low.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFluoroscopy and fluoroscopy-guided interventions (FGIs):\u003c\/strong\u003e Diagnostic fluoroscopy may help diagnose or treat cancer through biopsy or port placement for chemotherapy. It is also used to treat or manage conditions that are common in pregnancy. These conditions include iliofemoral deep vein thrombosis (a blood clot in the leg) and embolism (a blockage in a blood vessel). When the fetus is outside the field of view (FOV), FGI fetal dose will be below 1 mGy. However, if the fetus is in the FOV during a prolonged procedure, fetal dose may exceed 100 mGy. The benefits and risks should be weighed against alternative treatments. Fetal time in the FOV should be limited.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eComputed tomography (CT):\u003c\/strong\u003e No protocol adjustments are required when the fetus is outside the FOV, as fetal doses are below 1 mGy. For multi-phase exams where the fetus is inside the FOV, modifications should be considered. These modifications include reducing the scan range or conducting a single-phase study.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIodinated contrast agents:\u003c\/strong\u003e Iodinated contrast crosses the placenta but does not affect short-term neonatal thyroid stimulating hormone (TSH). Long-term effects on TSH function are unknown, but iodinated contrast agents are recommended during pregnancy when needed for accurate diagnosis. Importantly, management of contrast reactions may be different for pregnant patients.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNuclear medicine (diagnostic):\u003c\/strong\u003e Fetal doses in nuclear medicine depend on radiopharmaceutical accumulation in the fetus and nearby patient organs. Positron emission tomography (PET) is the most common diagnostic nuclear medicine exam in this population, because cancers that are common during pregnancy exhibit strong F-18-FDG uptake. Most diagnostic nuclear medicine studies use low administered activities of radiopharmaceuticals with short half-lives, resulting in fetal doses below 5 mGy. Fetal thyroid doses can be substantial for I-131 (over 40 Gy), which is contraindicated for diagnosis and therapy during pregnancy.\u003c\/p\u003e\n\n\u003ch2 id=\"doses-imaging\"\u003eTypical Fetal Doses from Imaging Exams\u003c\/h2\u003e\n\n\u003cp\u003eThe exact fetal dose depends on imaging parameters, pregnancy stage, and patient body size. Any x-ray-based exam where the pregnant uterus is not in the field of view results in a fetal dose below 1 mGy, and no imaging protocol modifications are necessary. For most x-ray-based exams where the fetus is in the field of view, fetal dose is under 10 mGy. Exceptions include CT and fluoroscopy-guided interventions, where doses can exceed 50 mGy. If multiple imaging exams are necessary, the cumulative dose should be considered.\u003c\/p\u003e\n\n\u003cp\u003eEstimated fetal doses for specific exams used in cancer staging, diagnosis, and follow-up include:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eChest x-ray (1 view):\u003c\/strong\u003e fetus not in field of view; dose 0.001 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAbdomen, pelvis, or lumbar spine x-ray (1 view):\u003c\/strong\u003e fetus in field of view; dose 0.1-3 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDiagnostic barium enema study:\u003c\/strong\u003e fetus in field of view; dose 1.0-20 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIVC filter placement:\u003c\/strong\u003e fetus in field of view; dose 2-4 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePercutaneous nephrostomy:\u003c\/strong\u003e fetus in field of view; dose 7 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eScreening or diagnostic mammography:\u003c\/strong\u003e fetus not in field of view; dose less than 0.01 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStereotactic breast biopsy:\u003c\/strong\u003e fetus not in field of view; dose less than 0.01 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCT head or neck:\u003c\/strong\u003e fetus not in field of view; dose 0-0.005 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCT chest:\u003c\/strong\u003e fetus not in field of view; dose 0.01-0.82 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCT abdomen:\u003c\/strong\u003e fetus in field of view; dose 1.3-35 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCT colonography:\u003c\/strong\u003e fetus in field of view; dose 9-16 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCT abdomen\/pelvis:\u003c\/strong\u003e fetus in field of view; dose 10-50 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTc-99m sulfur colloid lymphoscintigraphy (18.5 MBq):\u003c\/strong\u003e dose less than 0.01-0.05 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTc-99m sulfur colloid lymphoscintigraphy (92.5 MBq):\u003c\/strong\u003e dose 0.03-4.3 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eI-123 NaI scintigraphy (7.4 MBq):\u003c\/strong\u003e dose 0.01-0.6 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eI-131 thyroid uptake (0.55 MBq):\u003c\/strong\u003e whole body dose 0.03-0.15 mGy; thyroid dose 275-600 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eI-123 thyroid uptake (30 MBq):\u003c\/strong\u003e whole body dose 0.3-0.6 mGy; thyroid dose 150-450 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTc-99m DMSA scintigraphy (222 MBq):\u003c\/strong\u003e dose 0.75-1.12 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eI-131 metastases imaging (40 MBq):\u003c\/strong\u003e whole body dose 2-11 mGy; thyroid dose 20,000-44,000 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eF-18 FDG PET only (370 MBq):\u003c\/strong\u003e dose 3-10 mGy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGa-67 citrate scintigraphy (185 MBq):\u003c\/strong\u003e dose 18-38 mGy\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eTo estimate an overall risk, given the numerous uncertainties, it can be assumed that the values shown represent whole-body fetal dose unless otherwise indicated.\u003c\/p\u003e\n\n\u003ch2 id=\"radiation-therapy\"\u003eRadiation Therapy During Pregnancy\u003c\/h2\u003e\n\n\u003cp\u003eMany cancers outside the pelvis may be safely treated with radiation. Pelvic radiation, however, may cause severe or lethal fetal consequences. While no strict dose limitation guidelines exist, most sources state that deterministic effects may occur above 100 mGy. Therapeutic radiation should aim to keep fetal dose below this threshold.\u003c\/p\u003e\n\n\u003cp\u003eFor extremity, head and neck, and brain sites, fetal doses can be kept below 100 mGy with few additional accommodations. However, fetal dose should still be closely monitored. For chest, abdomen, and upper thigh sites, fetal doses may exceed 100 mGy. This necessitates shielding and other fetal-dose reduction strategies. When fetal dose is likely to exceed 100 mGy, the patient's risks from foregoing radiation should be weighed against fetal risks.\u003c\/p\u003e\n\n\u003cp\u003eSeveral relevant guidelines from professional organizations and consensus groups exist. However, many contain limited radiation-specific information or are outdated. The American Association of Physicists in Medicine (AAPM) Task Group Report 36 contains recommendations for estimating and reducing fetal dose but does not discuss modern treatment modalities. The French Society for Radiation Oncology practice guidelines on radiotherapy and pregnancy reported that radiation above the diaphragm can be safely delivered. The guidelines also reported that phantom and in vivo dose measurements should be performed. Multiple review papers have also been published, but many contain limited or misleading radiation information. In many cases, the benefit of radiotherapy outweighs the fetal risks.\u003c\/p\u003e\n\n\u003ch2 id=\"disease-sites\"\u003eCancer Types and Radiation Treatment\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eHead and neck cancer:\u003c\/strong\u003e Radiotherapy is often important for treating the primary tumor and lymph nodes. Some sites may require radiotherapy alone or with chemotherapy because surgery would cause severe toxicities. Given the distance between the treatment site and the uterus, fetal dose can be kept below 100 mGy. Treatment decisions should focus on optimizing the patient's outcome.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCentral nervous system (CNS) cancer:\u003c\/strong\u003e Radiotherapy during pregnancy is most relevant for high-grade primary CNS tumors and brain metastases. For brain metastases, the primary cancer type, the extent and location of cancer inside and outside the brain, and systemic therapy options need to be closely weighed. Few options completely avoid the need for radiotherapy. Many aggressive primary brain tumors can be surgically removed, but adjuvant radiotherapy improves survival. If diagnosed early in pregnancy, radiotherapy should not be delayed for aggressive tumor types, because recurrence occurs quickly. Fortunately, the large distance from the uterus typically results in low fetal doses.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThoracic (chest) cancer:\u003c\/strong\u003e Most early-stage cancers can be managed with surgical removal and\/or chemotherapy, and local recurrence risks without radiotherapy are typically low. However, more extensive lung cancers are managed with primary radiotherapy, which can potentially be safely delivered with proper shielding and fetal dose reduction strategies. Treatment planning should consider pregnancy-related changes in lung function.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eBreast cancer:\u003c\/strong\u003e Diagnosis of breast cancer during pregnancy is often delayed and presents at a more advanced stage than in non-pregnant patients. A full staging workup is essential, as advanced disease may impact treatment decisions. Treatment management should follow standardized protocols for non-pregnant patients as closely as possible. Treatment typically includes surgery followed by radiation and systemic therapy. Radiotherapy decisions should consider gestational age, because fetal exposure increases later in pregnancy as the uterus becomes closer to the treatment field. This must be balanced against the impact of delaying radiation, which may affect local control. There is no consensus on the acceptable surgery-to-radiotherapy interval, with evidence for permissible delays varying from 6 to 20 weeks. Often, the standard treatment course may involve neoadjuvant chemotherapy, which may result in delaying radiotherapy until after pregnancy. If prompt radiotherapy is indicated, breast radiotherapy can be delivered relatively safely during the first and much of the second trimesters. There is ample evidence showing fetal doses are often below 100 mGy using shielding.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eLymphoma:\u003c\/strong\u003e Treatment options vary depending on the cancer type and stage, gestational age, and maternal symptoms. Generally, treatment occurs in the second and third trimester. Chemotherapy is the most common treatment, but lymphomas above the diaphragm can be safely treated with radiation if necessary. In some cases of asymptomatic Hodgkin lymphoma, treatment can be deferred until after delivery.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCervical cancer:\u003c\/strong\u003e The timing and manner of treatment is based on gestational age, tumor stage, and maternal wishes. For stages 1B1 or less, options include delay or more limited surgical approaches. For stages greater than 1B1, delivering standard-of-care chemoradiotherapy would induce abortion in 1-2 months. A short treatment delay to allow lung maturation could be considered in some third-trimester cases. Local abortion restrictions may limit options. In these situations, systemic therapy could be considered, but this risks inferior maternal outcomes.\u003c\/p\u003e\n\n\u003ch2 id=\"ebrt\"\u003eExternal Beam Radiation Therapy and Fetal Dose\u003c\/h2\u003e\n\n\u003cp\u003eAn alternative to photon external beam radiotherapy (EBRT) is pencil beam scanning proton therapy (PBS-PRT). PBS-PRT can produce fetal equivalent doses over ten times lower than photon EBRT for brain and head and neck cancers.\u003c\/p\u003e\n\n\u003cp\u003eWhen PBS-PRT is not available, it is possible to deliver photons or electrons using several techniques while maintaining fetal doses below 100 mGy. These techniques include 3D conformal radiotherapy (CRT), intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), CyberKnife, GammaKnife, and linac-based stereotactic radiosurgery (SRS).\u003c\/p\u003e\n\n\u003cp\u003eThough reports during pregnancy are limited, electrons have been used successfully for intraoperative breast cancer treatment and chest wall irradiation. Passive scattering proton therapy (PS-PRT) produces doses ten times greater than photon therapy and is not recommended during pregnancy.\u003c\/p\u003e\n\n\u003cp\u003eFetal dose for photon EBRT sites outside the uterus comes from three sources: internal patient scatter, treatment head leakage, and collimator scatter. Leakage and collimator scatter can be minimized through shielding and monitor unit (MU) reduction. Internal scatter can only be decreased by increasing the distance to the fetus or decreasing field size. Beyond the field edge, out-of-field dose decreases approximately exponentially.\u003c\/p\u003e\n\n\u003cp\u003eFor electron beams, out-of-field dose is mainly caused by scattered electrons originating from the primary beam or trimmer, and by collimator scatter. Electron beam out-of-field dose, particularly for certain linear accelerators, can exceed that of photons.\u003c\/p\u003e\n\n\u003ch2 id=\"implications\"\u003eWhat This Means for Patients\u003c\/h2\u003e\n\n\u003cp\u003eOverall, it is possible to safely and effectively deliver radiation to pregnant patients in numerous circumstances. The use of radiation or other treatment modalities should be discussed through shared decision-making between the physician and the patient. This discussion should put the maternal and fetal risks from treatments into context.\u003c\/p\u003e\n\n\u003cp\u003eFor many cancer types outside the pelvis, radiation can be delivered with fetal doses kept below 100 mGy. This threshold is important because deterministic radiation effects (those that occur above a threshold dose) are not relevant below this level. The stochastic risk (the probability of cancer occurring) is negligible or non-existent at these low doses.\u003c\/p\u003e\n\n\u003cp\u003ePatients should understand that delaying or avoiding standard cancer treatment can significantly harm their own health. For example, treatment delays of 4 months or longer in cervical cancer are associated with a 2.31 times increased risk of death. In most cases, pregnancy itself will not worsen prognosis unless treatment is declined because of fetal concerns.\u003c\/p\u003e\n\n\u003cp\u003eHealthcare providers should support wide access to reproductive healthcare to allow equitable, evidence-based, patient-centered care.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eLimitations and Gaps in Knowledge\u003c\/h2\u003e\n\n\u003cp\u003eThe authors highlight several gaps in existing knowledge and guidelines. Guidance for radiotherapy during pregnancy is sparse and scattered, unlike the ample resources available for surgery and systemic therapies.\u003c\/p\u003e\n\n\u003cp\u003eMany existing guidelines contain limited radiation-specific information or are outdated. The AAPM Task Group Report 36 does not discuss modern treatment modalities. Multiple review papers contain limited or misleading radiation information, such as recommending avoiding radiation except in \"rare scenarios in which the benefits exceed the risk.\"\u003c\/p\u003e\n\n\u003cp\u003eUncertainties in risk estimates below 100 mGy prevent accurate risk quantification. The long-term effects of iodinated contrast agents on thyroid function are unknown. Evidence of fetal risk from gadolinium-based contrast agents is limited.\u003c\/p\u003e\n\n\u003cp\u003eThere is no consensus on the acceptable surgery-to-radiotherapy interval for breast cancer during pregnancy, with evidence for permissible delays varying from 6 to 20 weeks. Reports on electron beam use during pregnancy are limited.\u003c\/p\u003e\n\n\u003cp\u003eLocal abortion restrictions may limit treatment options for cervical cancer during pregnancy. In these situations, systemic therapy could be considered, but this risks inferior maternal outcomes.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients and Providers\u003c\/h2\u003e\n\n\u003cp\u003eBased on this guide, the authors offer the following recommendations:\u003c\/p\u003e\n\n\u003col\u003e\n  \u003cli\u003eUse shared decision-making between the physician and patient to discuss radiation and other treatment modalities. Put the maternal and fetal risks from treatments into context.\u003c\/li\u003e\n  \u003cli\u003eFollow standard-of-care treatment when possible. Weigh risks to the patient and the fetus when considering deviation from standard treatment.\u003c\/li\u003e\n  \u003cli\u003eScreen for pregnancy before radiation therapy. Secure a negative pregnancy test within 14 days prior to external beam radiotherapy, or within 72 hours prior to therapeutic I-131 administration.\u003c\/li\u003e\n  \u003cli\u003eCounsel patients to prevent pregnancy during treatment and after radiopharmaceutical administration.\u003c\/li\u003e\n  \u003cli\u003eFollow breast cancer screening guidelines for the general population during pregnancy. Do not delay screening mammography because of pregnancy-related changes.\u003c\/li\u003e\n  \u003cli\u003eUse non-contrast MRI when the static magnetic field is 3T or less and the scanner is in normal operating mode.\u003c\/li\u003e\n  \u003cli\u003eAvoid gadolinium-based contrast agents except when the anticipated clinical benefit justifies the unknown risk.\u003c\/li\u003e\n  \u003cli\u003eAvoid I-131 for diagnosis and therapy during pregnancy.\u003c\/li\u003e\n  \u003cli\u003eKeep fetal dose below 100 mGy for therapeutic radiation when possible.\u003c\/li\u003e\n  \u003cli\u003eUse shielding and fetal-dose reduction strategies for chest, abdomen, and upper thigh treatment sites.\u003c\/li\u003e\n  \u003cli\u003eConsider pencil beam scanning proton therapy when available, as it produces fetal doses over ten times lower than photon therapy for brain and head and neck cancers.\u003c\/li\u003e\n  \u003cli\u003eAvoid passive scattering proton therapy during pregnancy, as it produces doses ten times greater than photon therapy.\u003c\/li\u003e\n  \u003cli\u003eAvoid delivery before 37 weeks unless medically necessary for the pregnant patient's health.\u003c\/li\u003e\n  \u003cli\u003eSupport wide access to reproductive healthcare to allow equitable, evidence-based, patient-centered care.\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\u003eI'm pregnant and just found out I have cancer. Can I still have radiation treatment?\u003c\/h3\u003e\n\u003cp\u003eYes, in many circumstances. A team of physicians, medical physicists, a patient advocate, and a lawyer reviewed guidelines and recent literature and concluded that radiation can be delivered safely and effectively to pregnant patients in many situations. Decisions should be made through shared decision-making between you and your physician, putting both maternal and fetal risks into context.\u003c\/p\u003e\n\u003ch3\u003eWhat fetal radiation dose is considered safe during pregnancy?\u003c\/h3\u003e\n\u003cp\u003eFor therapeutic radiation, the aim is to keep fetal dose below 100 mGy when possible. Below this threshold, deterministic effects (those occurring above a threshold dose) are not relevant, and stochastic risk (the probability of cancer) is negligible or non-existent. For many cancer types outside the pelvis, radiation can be delivered with fetal doses kept below 100 mGy.\u003c\/p\u003e\n\u003ch3\u003eI need imaging to stage my cancer. Which scans are safe during pregnancy?\u003c\/h3\u003e\n\u003cp\u003eMany imaging exams are safe. X-rays where the fetus is outside the field of view give fetal doses below 1 mGy. Non-contrast MRI is considered safe at 3T or less in normal operating mode. Ultrasound has no known risks. CT and fluoroscopy may exceed 50 mGy if the fetus is in the field of view, so modifications should be considered.\u003c\/p\u003e\n\u003ch3\u003eWhat does a fetal dose of 10-20 mGy mean for my baby's risk of leukemia?\u003c\/h3\u003e\n\u003cp\u003eA fetal dose of 10-20 mGy may increase the risk of leukemia by a factor of 1.5 to 2.0 over a background rate of about 1 in 3,000. Restated, there is a greater than 99% chance that a fetus exposed to 20 mGy will be unaffected. At 50 mGy, there is about a 98% chance the fetus will be unaffected.\u003c\/p\u003e\n\u003ch3\u003eWill delaying cancer treatment to protect my baby harm my own health?\u003c\/h3\u003e\n\u003cp\u003eYes, delaying or avoiding standard cancer treatment can significantly harm your health. For example, treatment delays of 4 months or longer in cervical cancer are associated with a 2.31 times increased risk of death. In most cases, pregnancy itself will not worsen prognosis unless you decline treatment because of concerns about the fetus.\u003c\/p\u003e\n\u003ch3\u003eDo I need a pregnancy test before starting radiation therapy?\u003c\/h3\u003e\n\u003cp\u003eYes, screening for pregnancy before radiation therapy is recommended. For external beam radiotherapy, a negative pregnancy test should be secured within 14 days prior to treatment initiation. For therapeutic I-131 administration, a negative serum pregnancy test should be obtained 72 hours prior. Each practice should develop a standardized policy.\u003c\/p\u003e\n\u003ch3\u003eCan I breastfeed after receiving a radiopharmaceutical?\u003c\/h3\u003e\n\u003cp\u003eSome radiopharmaceuticals are excreted in breastmilk. Generally, breastfeeding should cease for all I-131 labeled radiopharmaceuticals, Ga-67 citrate, and therapeutic administrations. Recommendations regarding the duration of interruption or cessation vary. An Authorized User or Nuclear Medicine Physician should be consulted for guidance specific to your situation.\u003c\/p\u003e\n\u003ch3\u003eIf I'm pregnant and diagnosed with cancer, when should I get a second opinion on whether radiation treatment is safe for my baby?\u003c\/h3\u003e\n\u003cp\u003eA second opinion is worth seeking when the recommended plan is to delay or avoid standard treatment because of fetal concerns, since delays of 4 months or longer in cervical cancer are associated with a 2.31 times increased risk of death. It is also reasonable when the treatment site is the chest, abdomen, or upper thigh, where fetal doses may exceed 100 mGy and shielding or other dose-reduction strategies are needed, or when proton therapy is being considered. 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 Pregnancy, cancer, and radiation-a modern refresher.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Kelly Kisling, Sandra M. Meyers, Rebecca Milman, Susan Richardson, Christina Chapman, Justine Dupere, Grace Eliason, Suzanne Evans, Titania Juang, Young Lee, Jeffrey Masten, Julia Maues, Rachel Newman, Mike Silosky, Catherine Song, Catheryn Yashar, and Sara Thrower\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication:\u003c\/strong\u003e JNCI Cancer Spectrum, 2026, Volume 10, Issue 2, pkag007\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDOI:\u003c\/strong\u003e https:\/\/doi.org\/10.1093\/jncics\/pkag007\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePublication date:\u003c\/strong\u003e Advance Access Publication Date: January 28, 2026\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eArticle type:\u003c\/strong\u003e Commentary\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthor affiliations:\u003c\/strong\u003e The authors represent institutions including the University of California San Diego, BC Cancer—Vancouver, University of Colorado Anschutz Medical Campus, Swedish Cancer Institute, Baylor College of Medicine, Mayo Clinic, Yale University, Elekta, Guiding Researchers and Advocates to Scientific Partnerships (GRASP), UTHealth McGovern Medical School, and MD Anderson Cancer Center.\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":47807313084572,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/da\/products\/pregnancy-cancer-and-radiation-a-modern-guide-for-patients","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}