Timing is everything: intraperitoneal chemotherapy after primary or interval debulking surgery for advanced ovarian cancer

Purpose: To evaluate the outcomes of intraperitoneal chemotherapy (IP) compared with those of intravenous chemotherapy (IV) in patients with advanced ovarian cancer after neoadjuvant chemotherapy (NACT) and interval debulking surgery (IDS) or primary debulking surgery (PDS). Methods: Patients with advanced epithelial ovarian carcinoma treated with PDS or NACT and IDS from 2006 to 2015 were identified. Comparative statistics were used to evaluate covariates, and survival rates were calculated using the Kaplan–Meier method and compared with log-rank tests. Results: Sixty-six patients received NACT followed by IDS with residual disease of ≤ 1 cm; 42 of these patients (63.6%) received IP therapy; and 24 patients (36.3%) had IV therapy only after IDS. The median progression-free survival (PFS) was 16.0 months in the IP group and 13.5 months in the IV group (p = 0.13). The estimated median overall survival (OS) was 64.0 months with IP and 50.0 months with IV (p = 0.44). During the same study period, 149 patients underwent optimal PDS after which 93 patients (62.4%) received IP and 56 patients (37.6%) were given IV chemotherapy. Patients after IP demonstrated improved survival outcomes when compared to patients after IV therapy. The median PFS was 28.0 months after IP and 16.5 months after IV (p = 0.0006), and the median OS was not reached for IP and 50.0 months after IV (p < 0.0001). Conclusions: Although IP chemotherapy after PDS is associated with improved survival, IP therapy after NACT and IDS, despite high rates of completion, may not have the same degree of survival advantage over IV therapy.