Moderate dose escalation with volumetric modulated arc therapy improves outcome in rectal cancer

Abstract

Background: Locally advanced rectal cancer is frequently treated with a long course of preoperative chemoradiotherapy. We investigated the effect of moderate dose escalation with volumetric modulated arc therapy (VMAT) up to 50 Gy in 25 fractions compared to 3D conformal radiotherapy (3D-CRT) to 45 Gy in 25 fractions in rectal cancer patients. Dose–volume parameters, acute toxicity, and complete response rates were compared. Material and Methods: For both groups, 65 patients were selected from our database through availability. Dose–volume parameters and acute toxicity data were compared using a Mann–Whitney U-test. Univariate and multivariate analyses correcting for tumor and nodal stage, distance to the mesorectal fascia and interval to surgery were used to compare complete response rates. Results: Lower mean doses to the small and large bowel were observed in the VMAT group compared to the 3D-CRT group (21 Gy vs. 29 Gy [p