Impact of Dose-Escalated Chemoradiation on Pathological Complete Response in Patients with Locally Advanced Rectal Cancer

Locally advanced rectal cancer requires a multimodal treatment. Radiotherapy is being explored for intensification to improve the rates of pathological complete responses (ypCR rates) which are correlated with better outcomes. This study reports a comparison between standard versus escalated doses in a preoperative scenario. The ypCR rates, toxicity, postoperative complications, and disease-free and overall survival at 5 years are described. From 2012 to 2019, 99 patients were analyzed retrospectively: standard arm (mean of 47.5 Gy) vs. dose-escalated arm (mean of 54.3 Gy). All patients were treated with 3DRT in 25 fractions, with concomitant capecitabine and surgery performed according to the total mesorectal excision principles in both arms. The ypCR was reported using the "College of American Pathologist grades"; the gastrointestinal (GI) and genitourinary (GU) toxicity was reported using the "Common Terminology Criteria for Adverse Events" (CTCAE 4.0). The ypCR rates were higher in the dose-escalated group (25% vs. 10.64%; <i>p</i> = 0.07), with a lower rate of non-treatment response (61.36% vs. 38.64%; <i>p</i> = 0.11). No statistical differences between the arms were found in terms of the oncological outcomes, postoperative complications (<i>p</i> = 0.15), second surgeries (<i>p</i> = 0.62), or deaths (<i>p</i> = 0.62). The CTCAE acute GI and GU toxicity were grade I or II in both arms. Our study presents a long-term follow-up in comparative cohorts.