Long-term results of single course of adjuvant intraportal chemotherapy for colorectal cancer. Swiss Group for Clinical Cancer Research (SAKK)

Abstract

The efficacy of adjuvant chemotherapy after surgery for colorectal cancer remains unproven. We have investigated the efficacy of a perioperative intraportal cytotoxic regimen in a randomised trial of 533 patients with operable colorectal carcinoma. Patients were randomly assigned either a single course of portal infusion with mitomycin (10 mg/m2, one dose) plus fluorouracil (500 mg/m2 per 24 h for 7 days) starting immediately after surgery, or no adjuvant treatment. 505 (94%) were evaluable. At median follow-up of 8 years, adjuvant therapy reduced the risk of recurrence by 21% (hazard ratio 0.79 [95% CI 0.62-1.00], p = 0.051) and the risk of death by 26% (0.74 [0.57-0.97], p = 0.026). The lower risk of relapse was observed in all subgroups based on node status or localisation of the tumour; the risk reduction was greatest in patients with tumour-involved lymph nodes (Dukes' C; 0.67 [0.45-0.99], p = 0.045) and for those with colon cancer (0.78 [0.56-1.09], p = 0.151). Most of the difference in overall and disease-free survival could be attributed to a consistent reduction of all kinds of tumour recurrences (local relapses, liver metastases, and other distant metastases) in the treated group, rather than to a reduction of liver relapses only. We conclude that part of the benefit obtained with a single course of adjuvant chemotherapy via the portal vein for patients with operable colorectal carcinoma might be due to the systemic effects of the portal chemotherapy.