The role of cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) in patients with peritoneal carcinomatosis (PC) of appendiceal origin (AO).

707 Background: Peritoneal carcinomatosis of mucinous appendiceal tumor origin is a rare condition which has poor prognosis if treated with limited surgery or systemic chemotherapy. Several publications show that CRS/HIPEC gives a significant survival benefit for patients with PC of AO. However, many patients do not get appropriate treatment. We show data from our 17-year experience using CRS/HIPEC in PC of AO. Methods: Retrospective analysis of a prospective database of 251 patients with PC of AO was performed. Peritoneal cancer index (PCI), completeness of cytoreduction (CC), lymph node (LN) status, and histopathology data was collected. The impact of each variable evaluated by Hazard ratio analysis. Overall survival (OS) estimated by Kaplan-Meier curves. Results: Mean age 53 years (range 23-81). 251 patients underwent 290 CRS/HIPEC procedures. 31 patients had 2, and 4 patients had 3 CRS/HIPEC. A total of 149 patients (59%) had peritoneal mucinous carcinomatosis (PMCA) and 102 (41%) had disseminated peritoneal adenomucinosis (DPAM) (Ronnett classification). Mean follow-up 4.8 years with a median of 4.7 years. Complete cytoreduction was achieved in 84% (89% DPAM, 80% PMCA; p = 0.047). Mean length of surgery 11.3 hours, mean hospital stay 14 days. No in-hospital or 30-day mortality. 73% had PCI > 20 (78% DPAM; 68% PMCA). LN metastasis in 42% with PMCA. OS from date of HIPEC was 93%, 86%, 81% in DPAM and 90%, 60%, 44% in PMCA for 1, 3, and 5 years, respectively. With CC, the 5-year OS was 84% in DPAM and 49% in PMCA. All PMCA patients with incomplete cytoreduction (n = 30) had PCI ≥ 20 (p < 0.001). Hazard ratios were 2.5 (95% confidence interval [95% CI] 1.3-4.5), 3.1 (95% CI 2.0-4.9), 3.6 (95% CI 2.1-6.2), for PCI < 20, complete cytoreduction, and histopathology (DPAM vs. PMCA), respectively. Hazard ratio (for LN status in patients with PMCA was 3.0 (95% CI 1.8-5.1). Conclusions: Meaningful survival could be achieved in PC of AO even with extensive peritoneal disease (PCI > 20). We consider CRS/HIPEC a standard of care for these patients. CRS/HIPEC should be provided in specialized centers by trained surgeons where complete cytoreduction could be frequently accomplished.