3-4 Cycles versus 6 Cycles Neoadjuvant Chemotherapy in Advanced-Stage Epithelial Ovarian Cancer: Survival Is Not Determined by the Number of Neoadjuvant Chemotherapy Cycles.

Introduction: The aim of this study was to compare the disease-free survival (DFS) and overall survival (OS) of patients who underwent interval cytoreductive surgery after 3-4 cycles or 6 cycles of neoadjuvant chemotherapy (NACT) in advanced epithelial ovarian cancer patients.

Methods: Out of 219 patients with advanced epithelial ovarian cancer, 123 patients received 3-4 cycles and 96 patients received 6 cycles of platinum-based NACT. Afterward, laparotomy was performed for interval cytoreductive surgery.

Results: No statistically significant difference was found for DFS and OS of the patients who received 3-4 cycles and those who received 6 cycles of NACT (HR: 1.047, 95.0% CI [0.779-1.407]; p: 0.746 for DFS, and HR: 1.181, 95.0% CI [0.818-1.707]; p: 0.368 for OS). Evaluating 123 patients who received 3-4 cycles of NACT, 87 patients (70.7%) without macroscopic residual tumor after interval cytoreductive surgery had significantly longer DFS and OS compared to 36 patients (29.3%) with any residual tumor (HR: 1.830, 95.0% CI [1.194-2.806]; p: 0.003 for DFS, and HR: 1.946, 95.0% CI [1.166-3.250]; p: 0.009 for OS). 96 patients who received 6 courses of NACT were evaluated; 63 patients (65.6%) without macroscopic residual tumor after interval cytoreductive surgery had significantly longer DFS and OS than 33 patients (34.4%) with any residual tumor (HR: 1.716, 9 5.0% CI [1.092-2.697]; p: 0.010 for DFS, and HR: 1.921, 95.0% CI [1.125-3.282]; p: 0.013 for OS).

Conclusion: In patients with advanced ovarian cancer, there is no significant difference in DFS and OS between 3 and 4 cycles or 6 cycles of NACT. The most important factor determining survival is whether macroscopic residual tumor tissue remains after interval cytoreductive surgery following NACT.