DISEASE CHARACTERISTICS: Primary diagnosis of adenocarcinoma of the colon or rectum and meeting one of the following risk criteria during the primary surgery: Perforated bowel (spontaneous or not) Occlusion Peritoneal deposits Invasion of serosa of more than 4 cm diameter Concurrent ovarian metastases Randomization eligibility: Presence of proven recurrent peritoneal disease (only one micronodule of 1 mm sufficient) at second look laparotomy Total resection of macroscopic lesions possible (local recurrence, lymph node or hepatic metastases)