Adjuvant therapy in colon cancer--what, when and how?

Bolus fluorouracil and leucovorin has been accepted as the standard adjuvant therapy in stage III colon cancer for many years. New drugs such as irinotecan, oxaliplatin and oral fluoropyrimidines have all completed phase III randomised evaluation in colon cancer. Several of these studies have been reported in the last 24 months. Oxaliplatin-based chemotherapy is now emerging as the new standard of care in adjuvant treatment of stage III colon cancer. The advent of monoclonal antibodies such as cetuximab and bevacizumab has further broadened the treatment horizon for colorectal cancer and they are the focus of the on-going randomised studies in adjuvant therapy of colon cancer. In stage II colon cancer, adjuvant treatment remains controversial and is not routinely recommended in all medically fit patients by the current American Society of Clinical Oncology guidelines, except several subsets including poorly differentiated histology, T4 lesions, bowel perforation presentation and inadequately sampled lymph nodes (<13). This review focuses on the relative merits of these agents, their safety, duration of treatment, timing of commencing treatment after surgery and the role of adjuvant therapy in stage II colon cancer, thereby assisting clinicians in deciding the optimal adjuvant treatment for patients in routine clinical practice.