Long-term outcomes and survival analysis of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei at a newly established peritoneal malignancy centre in Japan.

Background: Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is established in the management of pseudomyxoma peritonei (PMP), selected cases of peritoneal mesothelioma, and resectable colorectal or ovarian peritoneal metastases in Western countries. However, the efficacy and feasibility of these techniques are not well established in the Asian population, and little has been reported on long-term survival outcomes for surgically resected PMP patients. Materials and Methods: Retrospective analysis of a prospective database of short- and longer-term outcomes of consecutive patients who underwent CRS and HIPEC for PMP in a newly established peritoneal malignancy unit in Japan between 2010 and 2016. Results: A total of 105 patients underwent CRS and HIPEC and 57 maximal tumor debulking (MTD) for pseudomyxoma peritonei. In the CRS group, the primary tumor was appendiceal in 94 patients (90%) followed by ovarian and colorectal. Major postoperative complications occurred in 22/105 patients (21%) with one in-hospital mortality (0.9%). The 5-year overall and disease-free survival rates for the CRS group were 74.2% and 50.1%, respectively. Multivariate analysis revealed unfavorable histology to be the significant predictor of reduced overall and disease-free survival. Completeness of cytoreduction, CA19-9, and CA125 were also associated with disease-free survival. Conclusions: This is the first report on long-term outcomes and survival analysis of CRS and HIPEC for PMP in the Asian population. CRS and HIPEC can be conducted with reasonable safety and favorable survival in a new center. Complete tumor removal and histological type are the strongest prognostic factors for both overall and disease-free survival.