Should We Be Doing Cytoreductive Surgery with HIPEC for Signet Ring Cell Appendiceal Adenocarcinoma? A Study from the US HIPEC Collaborative

Abstract

BackgroundAppendiceal adenocarcinoma with signet ring cells (SCA) is associated with worse overall survival (OS), and it is unclear whether cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) should be pursued in this patient population. We assessed the prognostic implications of signet ring cells in patients with appendiceal adenocarcinoma and peritoneal carcinomatosis undergoing CRS-HIPEC. MethodsThe US HIPEC Collaborative, a 12-center, multi-institutional database of patients undergoing CRS-HIPEC, was reviewed for patients with SCA. Univariate and multivariate analyses were performed. ResultsOf 514 patients undergoing CRS-HIPEC for appendiceal adenocarcinoma, 125 (24%) had SCA. The SCA and non-SCA groups had similar baseline characteristics. SCA had worse OS compared with non-SCA (32.0 vs 91.4 months, p < 0.001). In univariate analysis for only SCA cases, there was worse OS in patients with poorly differentiated tumors, positive lymph nodes, LVI, PCI > 20, or incomplete cytoreduction (CC-2/3). However, multivariate analysis showed only positive lymph nodes (HR 1.14 [95% CI 1.00–1.31], p = 0.04), poor differentiation (5.60 [1.29–24.39], p = 0.02), and incomplete cytoreduction (4.90 [1.11–12.70], p = 0.03) were independently associated with decreased OS for SCA. ConclusionWhile signet cells are a negative prognostic feature, they should not be a contraindication to CRS-HIPEC in patients with well-moderately differentiated tumors with negative lymph nodes, where complete cytoreduction can be achieved.