Assessment of Outcome in 198 Patients With Mucinous Appendiceal Adenocarcinoma and Peritoneal Metastases Over 25 Years

A prognostic assessment of mucinous appendiceal adenocarcinoma (MACA) patients with peritoneal metastases in the absence of lymph node metastases needs to be precisely defined. All patients were treated by a complete cytoreductive surgery (CRS) and perioperative chemotherapy. Preoperative clinical features including tumor markers were recorded within 1 week prior to CRS. Data regarding perioperative intraperitoneal chemotherapy, histologic features and reoperative surgery were gathered after CRS. Impact on overall survival of these factors was analyzed by univariant and multivariant analysis. One hundred and ninety‐eight patients with mucinous appendiceal adenocarcinoma causing pseudomyxoma peritonei were available for study. They had a median survival of 11 years. Hyperthermic intraperitoneal chemotherapy (HIPEC) with a median survival of 12.0 years was superior to early postoperative intraperitoneal chemotherapy (EPIC) with a median survival of 4.0 years (HR 2.09, p = 0.002). By histopathology, the intermediate type (MACA‐Int) was associated with the longest survival and poorly differentiated (MACA‐3) the poorest survival. Peritoneal cancer index and tumor marker elevations had no impact on survival. Clinical features and preoperative tumor markers had little or no prognostic value in selection of MACA patients for CRS. Intermediate histologic subtype and use of HIPEC indicated a favorable outcome.