Short-Course Radiation Therapy Versus Long-Course Chemoradiation in the Neoadjuvant Treatment of Locally Advanced Rectal Cancer: New Insights from Randomized Trials

Abstract

Examine prospective evidence supporting preoperative short-course radiotherapy (SCRT) and long-course chemoradiotherapy (LCRT) for locally advanced rectal cancer and discuss recently published data that are helping to clarify the utility of SCRT. SCRT with early surgery results in lower pCR rates, lower severe acute toxicities, no difference in late toxicities, and no apparent difference in local control, DFS, and OS when compared with LCRT. When surgery is delayed after SCRT, cancer outcomes appear equivalent, including pCR rates. The addition of full-dose systemic therapy with SCRT prior to surgery is attractive to further downstage patients, particularly in patients at high risk of distant relapse. Increasing randomized evidence is accumulating to support the use of SCRT as an acceptable preoperative treatment approach for locally advanced rectal cancer. Increasing the interval from SCRT to surgery and/or adding systemic doses of chemotherapy may mitigate potential concerns related to SCRT. More mature data and future results of ongoing randomized trials will help clarify the oncologic equivalence and safety of SCRT followed by preoperative chemotherapy.