Peritoneal mestastases from rare ovarian cancer treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC)

Objective: There are limited treatment options and no consensus on the management of advanced rare ovarian malignancies. Rare ovarian malignancies can present with peritoneal metastases (PM), featuring a similar presentation to more common ovarian subtypes. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is an effective treatment for PM of non-gynecologic origin and, recently, epithelial ovarian cancer. We evaluated the feasibility of CRS/HIPEC in the management of PM from rare ovarian malignancies and report postoperative outcomes on these patients.Methods: A retrospective review of a single center, prospective database (1994-2021) was performed to identify patients with rare ovarian malignancies treated with CRS/HIPEC. Clavien-Dindo 90-day morbidity/mortality and Kaplan-Meier overall (OS) and progression-free survival (PFS) were analyzed.Results: Of 44 patients identified, 28 underwent CRS/HIPEC. Six were aborted due to extensive disease. Histologic subtypes included: clear cell (5/28, 17.9 %), endometrioid (5/28, 17.9 %), granulosa cell (3/28, 10.7 %), low-grade serous (6/28, 21.4 %), mesonephric (1/28, 3.6 %), mucinous (6/28, 21.4 %), and small cell (2/28, 7.1 %) carcinomas. Eight (28.6 %) patients had primary and 20 (71.4 %) had recurrent disease. Median peritoneal cancer index (PCI) was 21 (IQR: 6-29). Complete cytoreduction (<2.5 mm residual disease) was achieved in 27/28 (96.4 %). Grade III/IV complications occurred in 9/28 (32.1 %) with one (3.6 %) mortality. After a median follow-up of 65.8 months, 20 patients were alive. Five-year OS and PFS were 68.5 and 52.6 %, respectively.Conclusions: In patients with PM from rare ovarian malignancies, CRS/HIPEC is feasible and has an acceptable safety profile. Longer follow-up and multicenter trials are needed.