Complete cytoreductive surgery (CCRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) is the gold standard for curative treatment of peritoneal carcinomatosis (PC) arising from colorectal cancer, peritoneal mesothelioma and peritoneal pseudomyxoma peritonei (PMP). The results of HIPEC remain controversial in PC that originates from ovarian cancer, stomach cancer, neuroendocrine tumors, or sarcoma. HIPEC has also been used, although very rarely, for other malignant carcinomatoses. Its use has been exceptional due either to the rarity of the tumor or because such disease is usually widespread and rarely confined to the peritoneum. The aim of this study was to evaluate the results of CCRS plus HIPEC in patients with PC of unusual origin.

We performed a retrospective analysis of all patients who underwent CCRS plus HIPEC for PC whose origin was neither gastric, ovarian or colorectal carcinoma, nor neuroendocrine tumor, mesothelioma, PMP or sarcoma.

Between 1995 and 2013, 31 patients with 15 PC arising from unusual primary tumors underwent CCRS plus HIPEC. After a median follow-up of 90 months, 10 patients were alive and without recurrence. The overall survival rate at 5 years was 33% with a median survival of 37 months. In univariate analysis, factors of poor prognosis and predictors of recurrence were the performance of immediate postoperative intraperitoneal chemotherapy instead of HIPEC and a peritoneal index ≥ 12. No prognostic impact due to tumor origin could be demonstrated.

The decision to perform CCRS plus HIPEC for PC arising from unusual cancer origins remains difficult. These patients should be prospectively entered into registries of rare tumors that involve the peritoneum in order to better define indications.