Adjuvant therapy for rectal cancer – the transatlantic view

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Abstract
In North America there are two conventional treatments for clinically resectable rectal cancer. First is surgery and, if the tumour is T3 and/or N1–2, this is followed by postoperative combined modality therapy. The second, for patients with ultrasound T3 or clinical T4 disease, is pre‐operative combined modality therapy followed by surgery and postoperative chemotherapy.Pre‐operative therapy (most commonly combined modality therapy) has gained acceptance as a standard adjuvant therapy. The potential advantages of this approach compared with postoperative therapy include less acute toxicity and enhanced sphincter preservation. Recently completed randomized trials in the US and Germany will provide a definitive answer to this theory. In contrast to the combined modality approach to pre‐operative therapy a number of European centres advocate an intensive short course of radiation (5 Gy × 5 followed one week later by surgery). The only randomized trial which has revealed a significant advantage in survival is the Swedish Rectal Cancer Trial. The Dutch CKVO 95–04 TME trial did not confirm a survival advantage and two metanalyses report conflicting results. Due to selection bias, it is not possible accurately to compare the local recurrence and survival results of intensive short course radiation with conventional pre‐operative combined modality therapy. The intensive short course radiation approach is not used in North America due to its higher toxicity and lack of sphincter preservation. In the Dutch trial the 5‐year local recurrence was 12% with TME and was significantly decreased to 6% with pre‐operative radiation. The 5‐year local recurrence rate in the 324 patients with stage III disease who underwent a TME alone with negative margins was 20%. Therefore, despite TME surgery, radiation therapy is still a necessary component in the adjuvant management of rectal cancer.