Practical Issues in Adjuvant Therapy for Rectal Cancer

Abstract

Introduction: While the standard adjuvant therapy for rectal cancer includes radiation therapy (RT) and chemotherapy (CT), the optimal treatment combination and sequencing have yet to be determined. In recent years, a large number of clinical trials have been reported in this rapidly evolving field. Materials and Methods: A review of pivotal trials in rectal cancer was undertaken with a focus on the important recent literature that has determined the current approach to adjuvant treatment. Results: Multiple well-conducted, randomised studies have demonstrated that, for patients with stage II and III rectal cancer, the combination of adjuvant CT and RT reduces the risk of local recurrence (LR) and distant recurrence, improves overall survival and should form part of the standard treatment. Due to the reduced risk of LR, the absolute benefit from adjuvant RT is less if optimal oncologic surgery has been performed. Theoretical advantages and preliminary clinical results suggest that delivering part of the adjuvant therapy preoperatively will produce superior results. Ongoing randomised trials will define the relative merits of long-course RT (with CT) and short- course RT alone as preoperative therapy. Preoperative combined modality therapy might increase the rate of sphincter preservation, although definitive data supporting this is still being awaited, whereas RT alone does not facilitate sphincter preservation. Conclusion: Management of patients with rectal cancer is complex and requires ongoing close collaboration between the colorectal surgeon, medical oncologist and radiation therapist in order to achieve the best possible outcomes. The optimal combination of CT and RT will be defined by current clinical trials.