Survival benefit of platinum-based chemotherapy in non-surgically treated advanced ovarian cancer: A nationwide study

OBJECTIVE: Patients with ovarian cancer who do not undergo surgery are underreported in literature. This study evaluated the impact of chemotherapy on survival in ovarian cancer patients who did not undergo cytoreductive surgery. Survival was compared between those who initiated chemotherapy and those who did not, and between patients who continued beyond three cycles and those who discontinued, adjusting for patient characteristics. METHODS: All patients diagnosed with ovarian cancer between 2018 and 2022 and not surgically treated were identified from the Netherlands Cancer Registry. Kaplan-Meier and Accelerated Failure Time models were used to evaluate the association between chemotherapy and survival. RESULTS: In total, 1780 patients who did not undergo cytoreductive surgery were included, 57.2% (N = 1018) were treated with platinum-based chemotherapy. Median overall survival in patients who initiated chemotherapy was 11.1 months (95% CI: 10.48-12.16) versus 1.8 months (95% CI: 1.74-2.07) in patients who did not (p < 0.0001). In multivariable analysis, chemotherapy was associated with longer survival (Time Ratio: 4.10, 95% CI: 3.35-5.01, p < 0.0001). Of patients who started chemotherapy, 70.5% (N = 691) received at least three cycles, and 47.9% (N = 469) received six cycles. Median overall survival in patients who stopped after three cycles was 9.9 months (95% CI: 8.1-12.4) versus 17.4 months (95% CI: 16.0-19.1) in patients who continued (p < 0.001). Continuation beyond three cycles was associated with longer survival (Time Ratio: 1.58, 95% CI: 1.24-2.01, p < 0.001). CONCLUSION: These findings support continuing platinum-based chemotherapy for up to six cycles in patients who do not undergo surgery, as this is associated with improved overall survival.