Peritoneal Carcinomatosis of Urachus Origin Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC): An International Registry of 36 Patients.

PURPOSE: Peritoneal carcinomatosis or pseudomyxoma peritonei from urachus is a rare form of presentation, often diagnosed at an advanced state of tumor burden. Because of its rarity, little is known about its natural history, prognosis, or optimal treatment. We searched a large international multicenter database of peritoneal surface disease to identify cases of peritoneal carcinomatosis of urachus that were treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) at expert centers. The aim is to improve knowledge and understanding of the disease and standardize its treatment. METHODS: A prospective multicenter international database was retrospectively searched to identify all patients with urachus tumor and peritoneal metastases who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI). Postoperative complications, long-term results, and principal prognostic factors were analyzed. RESULTS: The analysis included 36 patients. After median follow-up of 48 months, median overall survival (OS) was 58.5 months. Three- and 5-year OS was 55.4 and 46.2%, respectively. Patients who underwent complete macroscopic CRS had significantly better survival than those treated with incomplete CRS, with median OS not achieved and of 20.1 months, respectively [95% confidence interval (CI) 4.4-30.5, p < 0.001]. There were no postoperative deaths, and 37.9% of patients had major complications. CONCLUSION: CRS and HIPEC may increase long-term survival in selected patients with peritoneal metastases of urachus origin, especially when complete CRS is achieved.