Peritoneal dissemination from high-grade appendiceal cancer treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC)

Background: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have shown variability in survival outcomes when used to treat peritoneal surface disease (PSD) from appendiceal and colorectal cancers. The primary goal of this study was to examine outcomes for high-grade appendiceal (HGA) and high-grade colonic primaries after CRS-HIPEC to determine if a significant difference exists between the two groups. Methods: A retrospective analysis of patients with peritoneal dissemination from appendiceal and colonic primaries were identified in a prospectively maintained database of 1,223 CRS-HIPEC procedures performed between 1991 and 2015. Patient demographics, performance status resection status, tumor grade, nodal status, morbidity, mortality, and survival were reviewed with biopsy-proven PSD being classified according to primary site. Univariate and multivariate analyses were performed, and outcomes compared. Results: The study identified 171 CRS-HIPEC procedures for 165 patients: 110 (66.7%) for HGA and 55 (33.3%) for high-grade colonic lesions. Observed median disease-free survival (DFS) and overall survival (OS) for both groups were the same at14.4 and 18 months, respectively. Median survival according to resection status for R0/R1, R2a, and R2b/c were 36, 15.6, and 8.4 months (P<0.0001). Median OS for those who received preoperative chemotherapy versus those who did not were 14.4 and 20.4 months, respectively (P=0.01). For those who received preoperative chemotherapy, no difference was apparent in the DFS interval (P=0.34). Multivariate predictors of OS included resection status (P<0.0001) and lymph node involvement (P=0.0005). Conclusions: Preoperative chemotherapy offered no clear DFS or OS benefit, for HGA or high-grade colon cancer patients. Complete cytoreduction offered the greatest survival benefit to both groups with a correlating drop in survival to resection status. Outcomes for high grade appendiceal cancer are remarkably similar to colon cancer.