Future of Radiotherapy Delivery in Rectal Cancer— European and US Approaches

Abstract

Neoadjuvant radiation therapy is integral in the management of patients with localized rectal cancer. In parts of Europe, patients with operable rectal cancer are treated with short-course radiation therapy delivered in five daily, 5 Gy fractions to a total dose of 25 Gy, followed by surgery within 1 week. In the US, the standard for locally advanced rectal cancer is neoadjuvant chemoradiotherapy. This approach is principally based on the results of the German Rectal Cancer Study Group trial evaluating preoperative compared with postoperative chemoradiation. Surgery is typically performed at 4–8 weeks following completion of long-course chemoradiotherapy, facilitating tumor downstaging, and potential sphincter sparing surgery. No significant difference in clinical outcomes has been observed between these two approaches in two randomized clinical trials; however, further follow-up of these studies and new results from ongoing trials are anticipated to further clarify the optimal neoadjuvant treatment strategy.