Prognostic value of complete metabolic response on ¹⁸F-FDG-PET/CT after three cycles of neoadjuvant chemotherapy in advanced high-grade serous ovarian cancer

We investigated the prognostic value of complete metabolic response (CMR) on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) after 3 cycles of neoadjuvant chemotherapy (NAC) in advanced high-grade serous ovarian cancer (HGSC). PET/CT at baseline and after 3 cycles of NAC were performed; peak standardized uptakes were measured. PET parameters were compared with NAC parameter: cancer antigen-125 (CA-125) normalization before interval debulking surgery (IDS) and chemotherapy response score (CRS) to predict platinum-sensitivity. Kaplan-Meier analysis was used to determine correlations between PET parameters and survival. Prognostic factors were obtained by multivariate Cox regression analysis. Between 2007 and 2020, 102 patients were recruited: 19 (18.6%) were designated as CMR group and 83 (81.4%) as non-CMR group. CMR after 3 cycles of NAC showed the highest accuracy in predicting platinum-sensitivity (area under the curve [AUC]=0.729; 95% confidence interval [CI]=0.552-0.823; p=0.017), compared with CA-125 normalization before IDS (AUC=0.626; 95% CI=0.542-0.758; p=0.010) and CRS (AUC=0.613; 95% CI=0.490-0.735; p=0.080). CMR demonstrated better prognosis than non-CMR in progression-free survival (PFS) (median PFS, 23.9 months vs. 16.4 months; p=0.021) and overall survival (OS) (median OS, not reached vs. 69.7 months; p=0.025). In multivariate analysis, CMR was associated with a lower risk of recurrence (adjusted hazard ratio [aHR]=0.50; 95% CI=0.27-0.92; p=0.027) and death (aHR=0.23; 95% CI=0.05-0.99; p=0.048). CMR after 3 cycles of NAC can be a prognostic factor for both recurrence and death in advanced HGSC.