Impact of multidisciplinary therapy on high-grade appendiceal adenocarcinoma (AA)

4134 Background: AA is a rare malignancy ranging from well-differentiated to poorly differentiated carcinoma, including those with signet ring cells. Optimal therapy for low grade peritoneal disease is cytoreductive surgery (CRS) combined with heated intraperitoneal chemotherapy (HIPEC). However, some patients (pts) are suboptimal for CRS/HIPEC, and are considered for systemic chemotherapy (SC) alone, or SC + CRS. In light of our previously reported overall survival (OS) benefits for the role of SC in metastatic AA, here we explore the impact of surgical intervention on OS in these pts. Our aim was to clarify the OS benefit of multidisciplinary therapy (SC + CRS + HIPEC) in those pts with aggressive tumor biology. Methods: A retrospective chart review of AA pts registered in our tumor registry between Jan. 2005 to Dec. 2009 was undertaken to identify patients with AA who received SC. Electronic medical records (EMR) were reviewed for CRS, HIPEC, histology, SC, and OS. The K-M method and Log-Rank test were used for statistical analysis. Results: Of 143 AA pts, 52 (36%) pts were high grade with 33 (23%) having signet ring cells. After a median follow-up of 35M, high grade tumors were noted to have worse OS overall (24M vs 56M, p