Background: Patients with peritoneal mucinous carcinomatosis (PMCA) of appendiceal origin and extensive disease are commonly advised against CRS/HIPEC. We hypothesize that CRS/HIPEC is a beneficial treatment for this group.
Methods: Retrospective analysis of 134 patients with appendiceal cancer treated with CRS/HIPEC was performed from a prospective database. Extent of disease, measured by peritoneal cancer index (PCI), was related to completeness of cytoreduction (CC), lymph node (LN) status, and prior surgery score (PSS). Overall survival (OS) was estimated by Kaplan-Meier curves. Test differences were calculated using log-rank test.
Results: A total of 77 patients (57%) had PMCA. Mean follow-up was 22 months with a median of 18 months. OS was 88%, 56%, and 40% for 1, 3, and 5 years, respectively. 68% had PCI ≥ 20. LN metastasis was found in 44% of patients in PCI ≥ 20 and PCI < 20 groups. 73% and 60% of patients had PSS of 2 or 3 in PCI ≥ 20 and PCI < 20 groups, respectively (P = .196). Complete cytoreduction was achieved in 65% of PCI ≥ 20 group and 96% of PCI < 20 group (P = .004). With complete cytoreduction, the 5-year OS was 45% in PCI ≥ 20 group and 66% in PCI < 20 group (P = .139). 18 of 19 patients with incomplete cytoreduction had PCI ≥ 20, with 3- and 5-year OS of 27% and 0%. Hazard ratios (by Cox regression) were 2.8 (95% confidence interval [95% CI] 0.8-10.2) and 3.6 (95% CI 1.5-8.8) for PCI < 20 and complete cytoreduction, respectively.
Conclusions: Meaningful long-term survival could be achieved in patients with PMCA even with extensive peritoneal disease. PCI ≥ 20 should not be used as an exclusion criterion when selecting these patients for CRS/HIPEC, and every effort should be made to achieve complete cytoreduction.