Can PARP Inhibitor Drugs Given Before Surgery Help Women with Advanced Ovarian Cancer?

Table of Contents

• Key Points
• Background: Why This Research Matters
• What Are PARP Inhibitors and How Do They Work?
• The Knowledge Gap: What We Still Do Not Know
• How This Review Was Conducted
• Overview of Current Clinical Trials
• Window-of-Opportunity Studies Before Primary Surgery
• PARP Inhibitors as Conversion Therapy
• PARP Inhibitors Versus Standard Chemotherapy Before Interval Surgery
• PARP Inhibitor Combinations Before Surgery
• PARP Inhibition Before Secondary Cytoreductive Surgery
• Perioperative Safety and Timing of Surgery
• Blood Count Toxicity and Surgical Readiness
• Transfusion Risk and Surgical Postponement
• Clinical Implications: What This Means for Patients
• Limitations: What This Review Could Not Prove
• Recommendations and Future Directions
• Frequently Asked Questions
• Source Information

Key Points

• PARP inhibitors before cytoreductive surgery are experimental and should only be used in clinical trials, not as routine care.
• Standard initial treatment remains primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery.
• Blood count drops (anemia, low platelets, low white cells) may delay surgery, increase transfusions, and raise bleeding or infection risk.
• The OPAL-C trial, comparing neoadjuvant niraparib with standard chemotherapy, was stopped early for futility.
• Future trials must measure surgical outcomes such as complete tumor removal, complications, and treatment timing, not only cancer response.

Background: Why This Research Matters

Cytoreductive surgery (surgery to remove as much visible cancer as possible) remains the most important treatment for advanced epithelial ovarian cancer. In high-grade serous ovarian cancer, most patients are diagnosed at an advanced stage. Early symptoms are vague, and the disease often progresses silently.

During debulking surgery, surgeons aim to remove all visible tumor deposits. Complete macroscopic cytoreduction (removing all cancer visible to the naked eye) is one of the strongest predictors of survival. It also determines which treatments patients receive afterward.

For patients with FIGO stage III–IV disease, doctors must choose between two initial approaches:

• Primary debulking surgery (PDS) — surgery first, followed by chemotherapy
• Neoadjuvant chemotherapy (NACT) — chemotherapy first, followed by interval debulking surgery (IDS)

The choice depends on several factors. These include how the disease is distributed, the patient's overall health, surgical risk, and the likelihood that the surgeon can remove all visible cancer. Hospital expertise and surgeon preference also play a role.

Doctors prefer primary debulking surgery when complete removal is possible with acceptable risk. They recommend neoadjuvant chemotherapy when upfront complete removal is unlikely or unsafe.

Surgeons assess resectability (whether the tumor can be removed) using imaging, disease distribution, performance status, other medical conditions, nutritional status, and scoring systems. In selected patients with extensive peritoneal disease, diagnostic laparoscopy (a minimally invasive look inside the abdomen) may help. Laparoscopic triage has been shown to reduce unnecessary open surgeries and improve patient selection for primary debulking surgery.

What Are PARP Inhibitors and How Do They Work?

PARP inhibitors are drugs that block a protein called poly(ADP-ribose) polymerase (PARP), which helps cancer cells repair damaged DNA. These drugs are currently approved mainly as maintenance therapy. Maintenance therapy means treatment given after chemotherapy to keep the cancer from coming back.

The greatest benefit is seen in patients with BRCA1/2-mutated tumors or homologous recombination-deficient (HRD) tumors. BRCA1 and BRCA2 are genes that normally help repair DNA. When these genes are mutated, cells lose an important DNA repair pathway. HRD means the cell's homologous recombination repair system is not working properly.

The biological rationale for PARP inhibitors in these patients is called synthetic lethality. Cancer cells with HRD are especially vulnerable to PARP inhibition because they already have a broken DNA repair system. Blocking PARP leaves them unable to repair DNA damage, and the cells die.

The idea behind using PARP inhibitors before surgery is that selected BRCA-mutated or HRD-positive tumors may already respond to these drugs before cytoreductive surgery. Laboratory studies support this concept. Patient-derived organoids (tiny tumor models grown in the lab) and spheroid models have shown sensitivity to olaparib and niraparib. This sensitivity was seen particularly in tumors with BRCA alterations or functional HRD.

These findings suggest that PARP inhibitors may have activity without concurrent DNA-damaging chemotherapy in molecularly selected models. In theory, this could reduce tumor burden, improve resectability, and provide a direct biological assessment of how the tumor responds before major surgery.

Table 1 in the original article summarizes the most important PARP inhibitors and their rates of serious blood-related side effects (grade 3 or higher). These rates vary widely by drug:

• Olaparib: decreased hemoglobin/anemia in 13–21% of patients, decreased neutrophils/neutropenia in 6–9%, decreased platelets/thrombocytopenia in 1–2.4%
• Niraparib: anemia in 18–33%, neutropenia in 13–23%, thrombocytopenia in 14–38%
• Rucaparib: anemia in 13–29%, neutropenia in 6–11%, thrombocytopenia in 2–6%
• Talazoparib: limited early-phase ovarian data available
• Pamiparib: anemia in 41.6%, neutropenia in 33.6%, thrombocytopenia in 4.4%
• Fuzuloparib: anemia in 25.1–31.0%, neutropenia in 12.6–12.8%, thrombocytopenia in 16.8–28.7%
• Senaparib: anemia in 29%, neutropenia in 25%, thrombocytopenia in 27%
• Veliparib: anemia in 38–41%, neutropenia in 58–62%, thrombocytopenia in 28–31% (combination therapy data)

The Knowledge Gap: What We Still Do Not Know

Existing literature on PARP inhibitors in ovarian cancer has focused mainly on maintenance therapy, molecular selection, mechanisms of synthetic lethality, and systemic cancer outcomes. In contrast, the specific surgical implications of giving PARP inhibitors before cytoreductive surgery remain poorly defined.

The scarcity of early preoperative PARP inhibitor trials probably reflects ethical, clinical, and logistical barriers. Standard primary debulking surgery or platinum-based neoadjuvant chemotherapy cannot be delayed without strong justification.

Preoperative PARP inhibition could theoretically be integrated into the surgical pathway at several points:

1. A short window-of-opportunity strategy before primary debulking surgery — designed mainly to assess feasibility, safety, and early biological response without delaying surgery
2. Neoadjuvant PARP inhibitor therapy as conversion therapy — in selected BRCA-mutated or HRD-positive patients with initially unresectable disease, where the goal is to convert the tumor to operable status and achieve complete cytoreduction
3. PARP inhibitors as an alternative to, or in combination with, standard platinum-taxane neoadjuvant chemotherapy — before interval debulking surgery
4. Preoperative PARP inhibitors before secondary cytoreductive surgery — in platinum-sensitive recurrent ovarian cancer, where response to PARP inhibitors may help assess tumor biology

Across all these scenarios, the central surgical question is whether PARP inhibitors can safely improve resectability and complete cytoreduction without compromising treatment timing.

How This Review Was Conducted

This was a narrative review based on a targeted literature search. The authors searched PubMed/MEDLINE, ClinicalTrials.gov, and relevant clinical trial registry records. They also included published study protocols, conference abstracts, and current clinical guidelines when directly relevant to preoperative or neoadjuvant PARP inhibitor strategies in ovarian cancer.

The search included studies available up to April 2026. Search terms included combinations of:

• "ovarian cancer"
• "high-grade serous ovarian cancer"
• "PARP inhibitor"
• "olaparib," "niraparib," "rucaparib"
• "neoadjuvant," "preoperative," "window of opportunity"
• "cytoreductive surgery," "interval debulking surgery," "secondary cytoreduction"

Studies were selected if they addressed PARP inhibitor use before cytoreductive surgery or neoadjuvant PARP inhibitor strategies in ovarian cancer patients. Because mature clinical evidence in this field remains limited, the authors also included trial protocols, registry entries, and conference abstracts when they provided information on ongoing or emerging strategies.

Overview of Current Clinical Trials

The use of PARP inhibitors before cytoreductive surgery remains investigational. Several ongoing or early-phase studies provide a framework for discussing this strategy from a surgical perspective. These studies differ in their clinical context.

Some evaluate a short preoperative window-of-opportunity before primary debulking surgery. Others assess PARP inhibitors as neoadjuvant treatment before interval debulking surgery. Some explore PARP inhibition before secondary cytoreduction in recurrent disease.

Current guidelines still define primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery as the standard initial approach for advanced ovarian cancer. Therefore, preoperative PARP inhibitor treatment should still be considered a trial strategy rather than routine care.

Table 2 in the original article summarizes ongoing trials that use different PARP inhibitor approaches. The key trials include:

• NANT (NCT04507841): A prospective, interventional, single-arm, open-label phase II study. It is active but not recruiting. The study evaluates niraparib monotherapy as neoadjuvant therapy in patients with HRD-positive advanced ovarian cancer. These patients have a low likelihood of achieving R0 resection (no visible tumor left after surgery). This low likelihood is based on imaging or laparoscopic evaluation. These patients cannot tolerate optimal primary debulking surgery due to poor conditions. Primary outcomes are R0 resection rate after neoadjuvant niraparib and objective response rate after treatment.
• AGO-OVAR27/WoO (NCT04644289): A multi-center, prospective, open-label phase II trial. It is recruiting. The study evaluates olaparib alone or olaparib plus durvalumab for a short preoperative period (maximum 28 days) before primary debulking surgery in patients with histologically proven high-grade epithelial ovarian cancer. Primary outcomes include successful completion of the window-of-opportunity treatment, adequate dose intensity, absence of treatment-related surgical delay, no clinical progression before surgery, and no toxicity interfering with perioperative management.
• OPAL-C (NCT06964165): An open-label phase 2 randomized controlled multicenter study. It was terminated after meeting pre-specified futility criteria. The study compared neoadjuvant niraparib with carboplatin plus paclitaxel chemotherapy in patients with HRD-positive FIGO stage III–IV ovarian cancer who were candidates for neoadjuvant treatment before interval debulking surgery. The primary outcome was unconfirmed objective response rate according to investigator-assessed RECIST v1.1 criteria.
• NEOCATS (NCT06650709): A single-arm, proof-of-concept phase 2 study. It was not yet recruiting at the time of the review (scheduled to begin on 1 November 2024). The study evaluates olaparib plus durvalumab plus bevacizumab in patients with suspected or confirmed high-grade serous ovarian cancer. These patients are not thought to be candidates for primary debulking surgery and are considered candidates for neoadjuvant chemotherapy. They are not known to have BRCA-mutation-associated high-grade serous ovarian cancer. Patients who respond after 2 cycles receive 1 further cycle, followed by interval cytoreductive surgery planned 3–4 weeks after completion of cycle 3 and at least 28 days after the last dose of bevacizumab. The primary outcome is objective response rate after triplet therapy according to investigator-assessed RECIST v1.1.
• NEO (NCT02489006): A phase II, open-label, randomized, multi-center study. It is active but not recruiting. The study evaluates preoperative olaparib before secondary cytoreductive surgery in patients with platinum-sensitive recurrent high-grade serous ovarian cancer eligible for secondary cytoreductive surgery. Primary outcomes are response to neoadjuvant treatment before secondary cytoreductive surgery and response rate to olaparib in the neoadjuvant period. The study also includes translational assessment of PARP modulation and DNA repair gene alterations.

Window-of-Opportunity Studies Before Primary Surgery

Window-of-opportunity studies represent the most conservative model of preoperative PARP inhibitor treatment. In this approach, a PARP inhibitor is given for a short period between diagnosis and planned primary debulking surgery.

The main goals are to evaluate feasibility, safety, and early biological response. The AGO-OVAR27/WoO trial is an example. It evaluates olaparib alone or in combination with durvalumab before primary debulking surgery in patients with high-grade epithelial ovarian cancer.

The surgical relevance of this model lies in whether preoperative PARP inhibitors can be safely introduced without delaying primary debulking surgery or compromising perioperative outcomes.

Similar studies may also be beneficial from a molecular perspective. They can provide paired tissue samples before and after PARP inhibitor exposure. This allows assessment of the DNA damage response, homologous recombination function, proliferation, changes in the immune microenvironment, and early resistance mechanisms.

However, because the treatment window is short, these trials are more likely to inform biological feasibility than to demonstrate meaningful tumor downsizing or improved resectability.

PARP Inhibitors as Conversion Therapy

Another strategy is using PARP inhibitors as primary therapy in patients with initially unresectable disease. The NANT study evaluates niraparib as neoadjuvant monotherapy in advanced ovarian cancer with HRD. It was designed to assess both efficacy and safety in a preoperative setting.

Neoadjuvant niraparib monotherapy has shown antitumor activity and favorable surgical outcomes. These include a promising objective response rate and R0 resection rate, with acceptable toxicity in patients with HRD-positive unresectable high-grade serous ovarian cancer.

These findings suggest that niraparib may represent a potential investigational alternative for selected patients who are unwilling or unable to receive standard neoadjuvant chemotherapy.

PARP Inhibitors Versus Standard Chemotherapy Before Interval Surgery

Another approach directly compares PARP inhibitor-based neoadjuvant therapy with standard platinum-taxane chemotherapy before interval debulking surgery. The OPAL-C cohort study compared neoadjuvant niraparib with platinum-taxane doublet chemotherapy in patients with HRD-positive FIGO stage III–IV ovarian cancer. These patients were candidates for neoadjuvant treatment followed by interval debulking surgery.

This trial design was relevant from a surgical perspective. It directly tested whether a molecularly targeted neoadjuvant approach could compete with standard platinum-taxane chemotherapy in preparing patients for interval debulking surgery.

However, the study was stopped after meeting pre-specified futility criteria. This indicates a low probability that the experimental strategy would demonstrate the expected clinical benefit if the trial were completed.

This finding is important. It highlights that replacing standard neoadjuvant chemotherapy with PARP inhibitor-based treatment is unlikely to succeed, even in a molecularly selected population.

PARP Inhibitor Combinations Before Surgery

PARP inhibitor-based combinations before surgery are also being explored. NEOCATS evaluates olaparib in combination with durvalumab and bevacizumab in newly diagnosed advanced ovarian cancer. Treatment is given before interval debulking surgery in responding patients. The AGO-OVAR27/WoO study also includes an olaparib plus durvalumab cohort before primary debulking surgery.

These approaches are biologically attractive because PARP inhibitors can be combined with immune checkpoint inhibitors and antiangiogenic therapy (drugs that block blood vessel growth to tumors).

The main surgical concern is potential toxicity. PARP inhibitors may cause anemia, thrombocytopenia, and neutropenia. Bevacizumab may affect wound healing and gastrointestinal safety. Immune checkpoint inhibitors may cause immune-related adverse events.

Therefore, combination strategies should be assessed using specific perioperative endpoints. These include:

• Surgical delay
• Preoperative blood counts
• Transfusion rates
• Wound complications
• Bowel complications
• 30-day and 90-day morbidity (complications occurring within 30 or 90 days after surgery)

PARP Inhibition Before Secondary Cytoreductive Surgery

Preoperative PARP inhibition has also been explored in recurrent ovarian cancer before secondary cytoreductive surgery. The NEO trial investigated neoadjuvant olaparib in patients with platinum-sensitive relapsed high-grade serous ovarian cancer eligible for surgery.

Cytoreductive surgery depends strongly on the ability to achieve complete resection. In this context, the NEO trial suggests that neoadjuvant olaparib followed by cytoreductive surgery is feasible and safe in patients with platinum-sensitive recurrent high-grade serous ovarian cancer.

Among patients with resectable disease at secondary cytoreduction, postoperative olaparib alone appeared comparable to chemotherapy followed by olaparib. It was associated with lower toxicity, suggesting a potential chemotherapy-free approach in this highly selected population.

From a surgical perspective, these findings are relevant because preoperative PARP inhibition may help identify tumors with favorable DNA repair vulnerability and less aggressive biology before operative intervention.

Ongoing translational analyses may further clarify biomarkers of response and resistance. The primary outcomes included differences in levels of PAR or PARP-1 before and after study treatment. They also included assessment of mutations in BRCA1/2, RAD51B, RAD51C, RAD51D, PPM1D, FANCM, BRIP1, PALB2, and BARD1 in germline tissue compared to tumor tissue.

However, these results should be interpreted cautiously. They cannot be directly extrapolated to the first-line setting, where patients are treatment-naive or minimally treated. In that setting, the standard pathway remains primary debulking surgery or platinum-based neoadjuvant chemotherapy followed by interval debulking surgery.

Perioperative Safety and Timing of Surgery

Preoperative PARP inhibition raises a clinical problem. Toxicities that are usually manageable in the maintenance setting may become clinically relevant when a patient is being prepared for extensive cytoreductive surgery.

In this context, anemia, thrombocytopenia, neutropenia, treatment interruptions, transfusion requirements, wound healing, and postoperative recovery are not only adverse events. They are also potential determinants of whether surgery can be performed safely and on time.

Blood Count Toxicity and Surgical Readiness

Hematologic toxicity (harm to blood cells) is the most important perioperative concern with preoperative PARP inhibition. In the maintenance setting, dose interruption or reduction is an acceptable approach. Before cytoreductive surgery, the same toxicity may lead to delay of surgery, reduced operative readiness, transfusion, or a change in treatment strategy.

This is particularly relevant because cytoreductive surgery for advanced ovarian cancer may involve bowel resection, diaphragmatic stripping, splenectomy, liver mobilization, peritonectomy, and other procedures. These procedures are associated with potential massive blood loss and postoperative infectious risk.

Each type of low blood cell count has distinct surgical implications:

• Anemia may reduce physiologic reserve before long operations, increase the likelihood of perioperative transfusion, and complicate recovery after multivisceral resection. Olaparib commonly causes anemia, leading to dose interruption or reduction. In the SOLO-1 trial, anemia was the most frequent adverse reaction leading to interruption or reduction. In the PAOLA-1 trial, anemia was also the most frequent reason for such interventions in the olaparib-bevacizumab arm. In a preoperative trial, hemoglobin decline should therefore be recorded not only as an adverse event, but as a surgical readiness variable.
• Severe thrombocytopenia (low platelet count) is particularly important for niraparib. In the PRIMA trial, thrombocytopenia emerged as one of the most characteristic and clinically relevant toxicities. This is particularly important in the preoperative setting, because platelet decline may directly affect operative readiness, increase bleeding risk, and potentially delay cytoreductive surgery. Thus, when niraparib is considered before surgery, thrombocytopenia should be monitored not only as a treatment-related adverse event but also as a perioperative safety variable. Although individualized starting doses reduce this risk, thrombocytopenia remains a key barrier to safe major surgery.
• Neutropenia (low neutrophil count) is perioperatively relevant because extensive ovarian cancer surgery often involves bowel surgery, long operative time, drains, and postoperative collections. Future preoperative studies should therefore report absolute neutrophil count immediately before surgery, postoperative infections, abscesses, anastomotic complications (problems with surgical connections in the bowel), and antibiotic use.

Transfusion Risk and Surgical Postponement

In standard maintenance therapy, transfusion is usually treated as a supportive intervention. In preoperative PARP inhibitor strategies, the surgical endpoint should be considered.

Preoperative anemia may increase the need for red blood cell transfusion before or during cytoreduction. Thrombocytopenia may require platelet transfusion or delay surgery. In general surgical practice, platelet transfusion is usually recommended when the platelet count is below 50 × 10⁹/L before major non-cardiac surgery.

These considerations mean that preoperative PARP inhibitor trials must track transfusion requirements and surgical delays as key outcomes. A delay in surgery could allow the cancer to progress. It could also delay the start of standard chemotherapy.

Clinical Implications: What This Means for Patients

For patients with advanced ovarian cancer, this review carries several important messages.

First, PARP inhibitors given before surgery are not yet standard treatment. They remain experimental and should only be used within a clinical trial. The standard initial approach is still primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery.

Second, the potential benefit of preoperative PARP inhibitors is theoretical at this stage. The idea is that these drugs might shrink tumors, make surgery easier, and improve the chance of complete tumor removal. But this has not been proven in large, mature clinical trials.

Third, the risks are real. PARP inhibitors can cause significant drops in red blood cells, white blood cells, and platelets. These blood count problems could delay surgery, increase the need for transfusions, and raise the risk of bleeding or infection around the time of surgery.

Fourth, one trial (OPAL-C) that directly compared neoadjuvant niraparib with standard chemotherapy was stopped early because it was unlikely to show benefit. This suggests that PARP inhibitors are not a simple replacement for standard chemotherapy before surgery.

Fifth, the NEO trial in recurrent ovarian cancer showed that neoadjuvant olaparib followed by surgery was feasible and safe in platinum-sensitive recurrent high-grade serous ovarian cancer. Postoperative olaparib alone appeared comparable to chemotherapy followed by olaparib, with lower toxicity. However, these results apply only to a highly selected group of patients with recurrent disease, not to newly diagnosed patients.

Limitations: What This Review Could Not Prove

This review has several important limitations that patients and clinicians should understand.

First, the evidence base is preliminary. Most studies are early-phase, single-arm, or ongoing. There are very few mature, randomized controlled trials with survival outcomes.

Second, the OPAL-C trial was terminated early due to futility. This means the strategy of replacing standard neoadjuvant chemotherapy with PARP inhibitor-based treatment did not show promise in the population studied.

Third, the NEO trial results cannot be directly extrapolated to the first-line setting. Patients with recurrent disease have often received prior treatment, which may affect how their tumors respond to PARP inhibitors.

Fourth, the review is a narrative review, not a systematic review or meta-analysis. The authors selected studies based on relevance rather than a comprehensive, protocol-driven search strategy.

Fifth, many of the trials discussed are ongoing or not yet recruiting. Their results are not yet available, so no conclusions can be drawn about their effectiveness or safety.

Sixth, the review does not provide specific numbers for survival outcomes, progression-free survival, or overall survival in the preoperative setting. These data are not yet mature.

Recommendations and Future Directions

The authors make several recommendations for future research and clinical practice.

First, future trials should include surgery-specific endpoints in addition to conventional oncologic outcomes. These endpoints should include:

• Complete cytoreduction rate (R0 resection rate)
• Perioperative complications
• Transfusion requirements
• Time to further treatment
• Surgical delay
• Preoperative blood counts
• Wound complications
• Bowel complications
• 30-day and 90-day morbidity

Second, preoperative PARP inhibitor therapy should only be used within clinical trials. It should not be offered as routine care outside of a research setting.

Third, patients considering preoperative PARP inhibitors should be carefully selected. The best candidates may be those with BRCA-mutated or HRD-positive tumors who are unlikely to achieve complete cytoreduction with standard approaches.

Fourth, blood counts should be monitored closely before surgery. Anemia, thrombocytopenia, and neutropenia should be treated as surgical readiness variables, not just as drug side effects.

Fifth, combination strategies that include PARP inhibitors plus immunotherapy or antiangiogenic therapy should be assessed with specific perioperative safety endpoints. These combinations may increase the risk of wound-healing problems, bleeding, infection, and immune-related side effects.

Sixth, translational research should continue to identify biomarkers that predict which tumors will respond to preoperative PARP inhibitors. This includes assessing DNA repair gene mutations and PARP activity levels in tumor tissue.

In conclusion, preoperative PARP inhibitor therapy is theoretically promising but remains an unproven strategy in ovarian cancer. Its future value will depend on prospective trials showing that it can safely improve resectability and complete cytoreduction without compromising treatment timing. Until then, patients should discuss the risks and benefits of clinical trial participation with their oncology team.

Frequently Asked Questions

Are PARP inhibitors approved to treat ovarian cancer before surgery?

No. PARP inhibitors are approved mainly as maintenance therapy after chemotherapy, not before surgery. Using them preoperatively remains experimental and should only be done within a clinical trial. The standard initial approach is still primary debulking surgery, or neoadjuvant chemotherapy followed by interval debulking surgery. Patients should discuss clinical trial participation with their oncology team.

What blood count problems can PARP inhibitors cause before surgery?

PARP inhibitors can cause anemia (low red blood cells), thrombocytopenia (low platelets), and neutropenia (low white blood cells). Rates vary by drug; for example, niraparib caused thrombocytopenia in 14–38% of patients in the data reviewed. Before surgery, these drops may delay the operation, increase transfusion needs, or raise bleeding and infection risk. Blood counts should be monitored closely as surgical readiness variables.

Could taking a PARP inhibitor before surgery delay my operation?

Yes, that is a real concern. Anemia, low platelets, or low white blood cells from PARP inhibitors may lead to surgical delay, reduced operative readiness, or transfusion. A delay could allow the cancer to progress or postpone standard chemotherapy. Future trials are recommended to track surgical delay and transfusion requirements as key outcomes, not just tumor response.

What did the OPAL-C trial find about niraparib before surgery?

OPAL-C compared neoadjuvant niraparib with standard carboplatin plus paclitaxel chemotherapy in patients with HRD-positive stage III–IV ovarian cancer before interval debulking surgery. It was stopped early after meeting pre-specified futility criteria, meaning it was unlikely to show the expected benefit. This suggests PARP inhibitors are not a simple replacement for standard chemotherapy before surgery, even in molecularly selected patients.

Did the NEO trial show that olaparib before surgery is safe?

In the NEO trial, neoadjuvant olaparib followed by cytoreductive surgery was feasible and safe in patients with platinum-sensitive recurrent high-grade serous ovarian cancer. Postoperative olaparib alone appeared comparable to chemotherapy followed by olaparib, with lower toxicity. However, these results apply only to this highly selected recurrent-disease group and cannot be directly extrapolated to newly diagnosed patients.

What should future trials measure besides tumor response?

Future trials should include surgery-specific endpoints in addition to conventional cancer outcomes. These include complete cytoreduction rate (R0 resection), perioperative complications, transfusion requirements, time to further treatment, surgical delay, preoperative blood counts, wound complications, bowel complications, and 30-day and 90-day morbidity. Measuring only cancer response and survival would miss important surgical risks and recovery issues.

Should I get a second opinion before agreeing to PARP inhibitor treatment before ovarian cancer surgery?

Preoperative PARP inhibitors are experimental and should only be given inside a clinical trial, not as routine care. Standard treatment remains primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery. A second opinion can help confirm whether you are a candidate for standard surgery, whether a trial fits your BRCA or HRD status, and how blood count risks such as anemia and thrombocytopenia could affect surgical timing. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: Preoperative PARP Inhibitors in Ovarian Cancer Trials: Connecting Molecular Oncology and Cytoreductive Surgery.

Authors: Miedziarek C, Caputa P, Bochyński H, Zaborowski MP, Nowak-Markwitz E.

Author affiliations: Division of Gynecological Oncology, Department of Gynecology, Poznan University of Medical Sciences, Poznan, Poland; Doctoral School, Poznan University of Medical Sciences, Poznan, Poland; Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland

Publication: Cancers 2026, volume 18, article 2157

DOI: https://doi.org/10.3390/cancers18132157

Publication dates: Received 23 June 2026; Revised 1 July 2026; Accepted 2 July 2026; Published 5 July 2026

Academic editor: Dik C. van Gent

Keywords: ovarian cancer; PARP inhibitors; cytoreductive surgery; neoadjuvant therapy; complete cytoreduction

This patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace discussion with a qualified healthcare provider. Patients should consult their oncology team about their individual treatment options.