Clinicopathologic and Prognostic Features in Patients with Peritoneal Metastasis from Mucinous Adenocarcinoma, Adenocarcinoma with Signet Ring Cells, and Adenocarcinoid of the Appendix Treated with Cytoreductive Surgery and Perioperative Intraperitoneal Chemotherapy

Abstract

Tumors that show a signet ring or adenocarcinoid histomorphology have been associated with a poor prognosis. This study aimed to analyze the clinicopathologic and prognostic features in patients with peritoneal metastasis from mucinous adenocarcinoma (PMCA), adenocarcinoma with signet ring cell (PMCA-S), or adenocarcinoid (PMCA-A) of the appendix treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy. Retrospective analysis of a prospectively maintained database for all patients treated for appendiceal adenocarcinoma from 1989 to 2012 was performed. The study cohort consisted of 494 patients including 361 patients with PMCA (73.1%), 80 patients with PMCA-S (16.2%), and 53 patients with PMCA-A (10.7%). The patients comprised 273 men (55.3%) and 221 women (44.7%) with a mean age at presentation of 50.7years for the PMCA-S patients, 47.3years for the PMCA patients, and 47.5years for the PMCA-A patients (p<0.03). The 3- and 5-year survival rates were respectively 51 and 38% for PMCA compared with 30 and 22% for PMCA-S and 26 and 15% for PMCA-A. The median survival time was 45.4months for PMCA compared with 18.9months for PMCA-S and 26.8months for PMCA-A (p<0.000). The groups did not differ significantly in the completeness of cytoreduction achieved, with 53.5% of the PMCA patients having a CC0/1 compared with 46.2% of the PMCA-S patients and 41.6% of the PMCA-A patients (p<0.20). In the multivariate analysis, the independent predictors of a reduced survival were incompleteness of cytoreduction, histomorphology of PMCA-S or PMCA-A, and distant metastasis. The findings showed that PMCA-S or PMCA-A histomorphology contributes to the poor prognosis associated with peritoneal metastasis from appendiceal adenocarcinoma. The independent predictors for a poor overall survival included incompleteness of cytoreduction, PMCA-S and PMCA-A histomorphology, and distant metastasis.