¹⁸F-FDG-PET/CT based total metabolic tumor volume change during neoadjuvant chemotherapy predicts outcome in advanced epithelial ovarian cancer.

Abstract

To evaluate the predictive potential of total metabolic tumor volume (MTV) reduction during neoadjuvant chemotherapy (NACT) with ¹⁸F-FDG-PET/CT in an advanced FIGO stage III/IV epithelial ovarian cancer (EOC) patient cohort. Twenty-nine primarily inoperable EOC patients underwent ¹⁸F-FDG-PET/CT before and after NACT. The pre- and post-NACT total MTV, in addition to the percentage MTV reduction during NACT, were compared with primary therapy outcome and progression-free survival (PFS). ROC-analysis determined an optimal threshold for MTV reduction identifying patients with progressive or stable disease (PD/SD) at the end of primary therapy. A multivariate analysis with residual tumor (0/>0), FIGO stage (III/IV) and MTV reduction compared to PFS was performed. The association between MTV reduction and overall survival (OS) was evaluated. The median pre- and post-NACT total MTV were 352 cm³ (range 150 to 1322 cm³) and 51 cm³ (range 0 to 417 cm³), respectively. The median MTV reduction during NACT was 89% (range 24% to 100%). Post-NACT MTV and MTV reduction associated with primary therapy outcome (MTV post-NACT p = 0.007, MTV reduction p = 0.001) and PFS (MTV post-NACT p = 0.005, MTV reduction p = 0.005). MTV reduction <85% identified the PD/SD patients (sensitivity 70%, specificity 78%, AUC 0.79). In a multivariate analysis, MTV reduction (p = 0.002) and FIGO stage (p = 0.003) were statistically significant variables associated with PFS. MTV reduction during NACT corresponded to OS (p = 0.05). ¹⁸F-FDG-PET/CT is helpful in NACT response evaluation. Patients with total MTV reduction <85% during NACT might be candidates for second-line chemotherapy and clinical trials, instead of interval debulking surgery.