The impact of number of cycles of neoadjuvant chemotherapy on survival of patients undergoing interval debulking surgery for stage IIIC-IV unresectable ovarian cancer: results from a multi-institutional study

Objectives: Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) may be a valuable treatment option in advanced ovarian cancer when primary cytoreduction is not feasible. However, a consensus on the ideal number of NACT cycles is still lacking. In the present investigation, we aimed to evaluate how number of cycles of NACT influenced patients' outcomes. Methods: Data of consecutive patients undergoing NACT and IDS were retrospectively reviewed in 4 Italian centers, and survival outcomes were evaluated. Results: Overall, 193 patients were included. Cycles of NACT were 3, 4, and at least 5 in 77 (40%), 74 (38%), and 43 (22%) patients, respectively. Patients undergoing 3 cycles experienced a similar disease-free survival (hazard ratio [HR], 1.12; 95% confidence interval [CI], 0.89-1.65; P = 0.20) but an improved overall survival (HR, 1.64; 95% CI, 1.05-2.4; P = 0.02) in comparison to patients receiving at least 4 cycles. Five-year overall survival was 46% and 31% for patients having 3 and at least 4 cycles. Ten-year overall survival was 26% and 18% for patients having 3 and at least 4 cycles (HR, 1.70; 95% CI, 1.13-2.55; P = 0.009). Using multivariate analysis, we observed that only Eastern Cooperative Oncology Group performance status correlated with overall survival (HR, 1.76; 95% CI, 1.2-2.49; P = 0.001). In addition, a trend toward worse overall survival was observed for patients with residual disease at IDS (HR, 1.29; 95% CI, 0.98-1.70; P = 0.06) and patients receiving at least 4 cycles (HR, 1.76; 95% CI, 0.95-3.22; P = 0.06). Conclusion: Our data underline the potential implication of number of cycles of NACT before IDS. Further prospective studies are warranted to assess this correlation.