[Status of portal perfusion in colorectal cancer. Swiss Study Group for Clinical Cancer Research]

533 patients with diagnosis of operable colorectal carcinoma were randomized to receive either a single course of portal infusion with Mitomycin-C (MMC) and 5-Fluorouracil (5-FU) starting immediately after operation, or no adjuvant treatment. Of these, 505 (94%) were evaluable. Over the median follow-up of 8 years, the adjuvant therapy reduced the risk of recurrence by 22% (Hazard ratio = 0.78%, 95% CI 0.61-0.99; P = 0.045). The relative reduction of relapse on death was similar in all subgroups (i.e. nodal status, localization). However, adjuvant portal chemotherapy proved to be most efficient in the subgroups of patients with tumor involvement of the regional lymph nodes (Dukes C) and of patients with colon cancer. Analysis of the pattern of relapse showed that most of the difference in overall and disease-free survival is to be attributed to a consistent reduction of all kinds of tumor recurrences (i.e. local relapses, liver metastases and/or other distant metastases) in the treated group, rather than to liver relapses alone. We conclude therefore, that part of significant benefit obtained for patients with operable colorectal carcinoma treated with a single course of adjuvant chemotherapy via the portal vein might be due to the additional systemic effects of the portal chemotherapy and further study of perioperative treatment with and without prolonged chemotherapy appears worthwhile.