Effect of Increased Number of Neoadjuvant Chemotherapy Cycles on Tumor Resectability and Pathologic Response in Advanced Stage Epithelial Ovarian Cancer

Abstract

Purpose: To identify the significance of the number of neoadjuvant chemotherapy (NACT) cycles on pathologic response and to define relationship between multiple cycles of NACT and the timing of interval debulking surgery (IDS) in epithelial ovarian cancer (EOC) patients.

Methods: This retrospective case-control study was carried out at the Baskent University in Ankara between 2007 and 2017. We reviewed 62 patients with advanced stage (IIIC-IV) EOC who received NACT in other institutes and operated in our clinic. On the basis of the number of NACT cycles, patients were divided into 2 groups: group 1 received 3 cycles and group 2 received 4 to 6 cycles.The influence of the number of NACT cycles on complete pathologic response, lymph node involvement, overall survival (OS), progression free survival (PFS), platinum resistance and residual tumor were evaluated.

Results: The median OS was 44.4 +/- 4.8 months and 48.8 +/- 4.49 months for group 1 and group 2 respectively (p=0.122). PFS was 19.3 +/- 3.75 months in group 1 and 24.3 +/- 4.67 months in group 2 (p=0.84). Tumor morphology according to lymph node involvement, no visible tumor and complete pathologic response were similar for both groups (p=0.49, p=0.79 and p=0.6 respectively). Pathological absence of residual disease were 13.6% vs 7.5% for group 1 and group 2 respectively (p=0.6) and complete pathologic response rate was 6/62 (9.67%). Platinum resistance developed in 4(18.2%) patients and 18(45%) patients in group 1 and 2 respectively (p=0.031). Complete resection rates were similar for both groups (p=0.9). After multivariate survival analyses, complete resection remained significant (p=0.000, odds ratio/ OR 2.28 [1.41-3.701]), and was independent of age, platinum resistance and number of NACT cycles. Complete resection rates were almost equal in each groups, (68.2% [15/22] and 67.5% [27/40] for group 1 and group 2 respectively (p=0.9)).

Conclusions: Our data suggests that giving more than 3 cycles of NACT is unnecessary because increased number of cycles did not change the resectability and complete pathologic response, while it increased platinum resistance. Moreover OS and PFS remained similar.