Peritoneal Carcinomatosis of Rare Ovarian Origin Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: A Multi-Institutional Cohort from PSOGI and BIG-RENAPE

Purpose: Ovarian cancer is the most common deadly cancer of gynecologic origin. Patients often are diagnosed at advanced stage with peritoneal metastasis. There are many rare histologies of ovarian cancer; some have outcomes worse than serous ovarian cancer. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) can be considered for patients with recurrence. This study was designed to assess the impact of CRS and HIPEC on survival of patient with peritoneal metastasis from rare ovarian malignancy. Methods: A prospective, multicentric, international database was retrospectively searched to identify all patients with rare ovarian tumor (mucinous, clear cells, endometrioid, small cell hypercalcemic, and other) and peritoneal metastasis who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI) and BIG-RENAPE working group. The postoperative complications, long-term results, and principal prognostic factors were analyzed. Results: The analysis included 210 patients with a median follow-up of 43.5 months. Median overall survival (OS) was 69.3 months, and the 5-year OS was 57.7%. For mucinous tumors, median OS and DFS were not reached at 5 years. For granulosa tumors, median overall survival was not reached at 5 years, and median DFS was 34.6 months. Teratoma or germinal tumor showed median overall survival and DFS that were not reached at 5 years. Differences in OS were not statistically significant between histologies (p = 0.383), whereas differences in DFS were (p < 0.001). Conclusions: CRS and HIPEC may increases long-term survival in selected patients with peritoneal metastasis from rare ovarian tumors especially in mucinous, granulosa, or teratoma histological subtypes.