Early and long-term outcome data on 2,298 patients with pseudomyxoma peritonei of appendiceal origin treated by a strategy of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

Abstract

532 Background: Pseudomyxoma peritonei (PMP) originating from an appendiceal mucinous neoplasm remains a biologically heterogeneous disease. The purpose of this study was to evaluate the outcome and long-term survival after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) consolidated through an International Registry study. Methods: A retrospective multi-institutional registry was established through collaborative efforts of participating units affiliated with the Peritoneal Surface Oncology Group International (PSOGI). Results: 2298 patients from 16 specialized units underwent CRS for PMP. Treatment related mortality was 2% and major operative complication was 24%. The median survival was 196 months (16.3 years) and the median progression-free survival was 98 months (8.2 years) with a 10- and 15-year survival rate of 63% and 59% respectively. Multivariate analysis identified prior chemotherapy treatment (P<0.001), PMCA histopathological subtype (P<0.001), major postoperative complication (P=0.008), high PCI (P=0.013), debulking surgery (CCR2/3) (P<0.001), not using HIPEC (P=0.030) as independent predictors for a poorer progression-free survival. Older age (P=0.006), major postoperative complication (P<0.001), debulking surgery (CCR2/3) (P<0.001), prior chemotherapy treatment (P=0.001) and PMCA histopathological subtype (P<0.001) were independent predictors of a poorer overall survival. Conclusions: The combined modality strategy for PMP may be performed safely with acceptable morbidity and mortality in a specialized unit setting with 63% of patients surviving beyond 10-years. Minimizing non-definitive operative and systemic chemotherapy treatments prior to definitive cytoreduction may facilitate the feasibility and outcome of this therapy to achieve long-term survival. Optimal cytoreduction achieves the best outcomes.