Prolongation of Neoadjuvant Chemotherapy before Surgery: Seeking the Optimal Number of Cycles in Serous Ovarian Cancer

Aim: The optimal number of neoadjuvant chemotherapy (NACT) cycles is unclear in epithelial ovarian cancer. Our study aimed to evaluate the effect of the number of NACT cycles before interval debulking surgery on survival. Methods: Data of 221 patients with advanced-stage serous epithelial ovarian cancer (EOC) were retrospectively evaluated. The patients were divided into groups as who received 3 cycles of NACT (group A), 4-5 cycles of NACT (group B), and 6 cycles of NACT (group C). Results: There were 67 (30%) patients in group A, 70 (32%) in group B, and 84 (38%) in group C. Median overall survival (OS) was 61 (range 43-79) months for group A, 44 (range 36-52) months for group B, and 39 (range 27-50) months for group C. In addition, median disease-free survival (DFS) was 23.1 (range 8.5-32.1) months for group A, 19.2 (range 10.1-28.4) months for group B, and 21.5 (range 16-27) months for group C. Patients receiving >3 NACT cycles had worse OS than patients who received 3 NACT cycles (for group A vs. B, p = 0.018; for group A vs. C, p = 0.049). However, in terms of DFS, patients receiving 3 NACT cycles had no statistically significant difference compared to patients who received >3 NACT cycles. Conclusions: Patients with advanced-stage serous EOC who received more than 3 cycles of NACT had poor OS. However, there was no statistical difference in terms of DFS. In addition, >3 cycles of NACT did not increase the probability of achieving complete cytoreduction at the time of surgery.