Adjuvant chemotherapy for colorectal cancer.

Colorectal cancer is the second most common cancer in the Western world, and yet the survival after potentially curative excisional surgery has improved little over the last half century. Newer tumour prognostic markers are not superior to conventional Dukes' staging and there are currently no markers which predict response to chemotherapy. Adjuvant chemotherapy has had a chequered past, but recently a number of important prospective studies have demonstrated its proven benefit in patients with Dukes' stage C colorectal cancer. However, several issues still require clarification. (1) Do immunomodulators such as levamisole have a significant role in adjuvant chemotherapy? (2) Which patients derive most benefit from adjuvant chemotherapy? (3) Do prognostic markers have a role in predicting these patients? Approximately 30% of patients with Dukes' stage B cancers die of metastatic disease and the role of adjuvant chemotherapy in patients with these tumours seems worth exploring. Only a large randomised trial can give answers to these important questions. Such a trial would also encourage the widespread introduction of standard methods of surgical and pathological assessment.