Appendiceal cancer and peritoneal carcinomatosis: a report of 29 cases

Peritoneal surface malignancies of appendiceal origin arise from a perforated neoplasm with gradual expansion of the tumor within the abdomen. We report our experience with 29 patients. Between February 2000 and November 2004, 29 patients were classified into one of three groups based on the features of their peritoneal dissemination. Group 1 included those with extracellular mucin with little cellular atypia (disseminated peritoneal adenomucinosis/low-grade mucinous adenocarcinomas). Group 2 included those with peritoneal mucinous carcinomatosis/high-grade mucinous adenocarcinomas, and Group 3 included those with nonmucinous carcinomatosis. There were 17 patients in Group 1, 9 in Group 2, and 3 in Group 3. The majority had cytoreductive surgery and intraperitoneal chemotherapy. There were no operative deaths. Mean follow-up was 21 months. Median survival for Groups 1 and 2 has not been reached. Group 3 patients were more likely to die than Group 1 patients, with a hazard ratio of 48.0 (P = 0.001), and Group 2 patients with a hazard ratio of 7.8 (P = 0.029). Median survival for Group 3 was 5 months. These data add to the growing evidence that supports cytoreductive surgery and intraperitoneal chemotherapy in a selected group of patients. Those with mucinous peritoneal dissemination are more likely to benefit from this approach. It appears that in patients with nonmucinous carcinomatosis, the biology of the tumor predicts their outcome.