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

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