Prognostic significance of the number of postoperative intraperitoneal chemotherapy cycles for patients with advanced epithelial ovarian cancer

Objective Phase 3 trials have demonstrated a survival advantage for patients with optimally debulked epithelial ovarian cancer who received intravenous (IV) and intraperitoneal (IP) chemotherapy compared with IV therapy alone. This was despite a significant proportion of patients in the IV/IP arms not completing all 6 planned cycles. Our objective was to evaluate the prognostic significance of the number of IV/IP cycles administered. Methods/Materials Data were analyzed for all patients with stage III to IV epithelial ovarian cancer who underwent optimal primary cytoreduction followed by 1 or more cycles of IV/IP chemotherapy from January 2005 to July 2011 at our institution. A landmark analysis was performed to associate progression-free survival (PFS) and overall survival (OS) with the number of IV/IP cycles given. Results We identified 201 patients; 26 (13%) received 1 to 2 cycles of IV/IP chemotherapy, 41 (20%) received 3 to 4 cycles, and 134 (67%) received 5 to 6 cycles. The 5-year PFS for patients who received 1 to 2, 3 to 4, and 5 to 6 cycles was 18%, 29%, and 17%, respectively. The 5-year OS for patients who received 1 to 2, 3 to 4, and 5 to 6 cycles was 44%, 54%, and 57%, respectively. There was no significant difference in PFS (P = 0.31) or OS (P = 0.14) between the 3 groups. The most common reason for discontinuing IV/IP therapy was treatment-related toxicity (77%). Postoperative complications were the most common reason for not initiating IV/IP therapy (42%) in patients who subsequently transitioned to it. Conclusions We did not detect a significant survival difference between patients who received 1 to 2, 3 to 4, or 5 to 6 IV/IP chemotherapy cycles. Women may still derive a survival benefit if they receive fewer than 6 IV/IP cycles.