Treatment of peritoneal carcinomatosis from colon or appendiceal cancer with induction intraperitoneal chemotherapy.

Colorectal cancer patients may present with peritoneal seeding of the abdominal cavity or develop it as recurrent disease. Peritoneal carcinomatosis has been regarded as a uniformly lethal clinical entity with no specific plan for management. Twenty-six patients with an established diagnosis of isolated spread of adenocarcinoma or cystadenocarcinoma of colorectal or appendiceal origin to peritoneal surfaces were treated with a combination of intraperitoneal 5-fluorouracil and intravenous mitomycin C. Three cycles of chemotherapy of 5 days each in duration were given once a month for 3 months. Two to 4 months after completion of chemotherapy, exploratory surgery and a cytoreductive procedure occurred. Responses to intraperitoneal chemotherapy were recorded at the time of cytoreductive surgery. Four of five patients with low-volume intraperitoneal adenocarcinoma had complete responses to induction chemotherapy. None of 18 patients with moderate- or large-volume cystadenocarcinoma had complete responses. The surgical procedure was facilitated by chemotherapy responses in patients with moderate-volume peritoneal carcinomatosis but not if large-volume disease was recorded. Surgical complications in patients treated by the induction approach were more frequent (p = 0.01) when compared with matched patients without intraperitoneal chemotherapy prior to cytoreductive surgery. This data may suggest that patients with low- or moderatevolume peritoneal carcinomatosis should be treated with induction chemotherapy because of a high rate of responsiveness. Large-volume peritoneal carcinomatosis from grade I cancer should have cytoreductive surgery prior to chemotherapy because of less responsiveness and the frequent surgical morbidity observed with the induction approach.