Abstract / Summary
Background/Objectives: To evaluate whether complete metabolic response (CMR) on 18F-FDG PET/CT after neoadjuvant chemotherapy (NACT) is associated with complete cytoreduction at interval debulking surgery (IDS), progression-free survival (PFS), and overall survival (OS) in patients with advanced high-grade serous tubo-ovarian carcinoma. Methods: This retrospective single-center cohort included 87 patients with FIGO stage III–IV high-grade serous carcinoma undergoing 18F-FDG PET/CT before and after NACT. Metabolic response was classified as CMR or non-CMR using criteria adapted from PERCIST. The primary outcome, complete cytoreduction (R0), was assessed using multivariable logistic regression adjusted for age, FIGO stage, and number of NACT cycles. PFS and OS were analyzed from the interval debulking surgery (IDS) landmark using the Kaplan–Meier method, and PFS was further evaluated with Cox regression. Results: CMR was observed in 34 patients (39.1%). Complete cytoreduction was achieved in 62 (71.3%) and was more frequent with CMR (85.3% vs. 62.3%; p = 0.025). CMR was independently associated with R0 (adjusted OR 3.56, 95% CI 1.18–10.75; p = 0.024; sensitivity 46.8%, specificity 80.0%, PPV 85.3%). In the IDS-landmark analysis, median PFS was longer in the CMR group (12.9 vs. 9.1 months; p = 0.027), but this association was attenuated and no longer significant after adjustment for R0. OS did not differ significantly between the groups (p = 0.259). Conclusions: Post-NACT CMR was independently associated with complete cytoreduction and may support preoperative risk stratification. However, given its limited sensitivity, CMR should not be used as the sole determinant for IDS.