Gender affects acute organ toxicity during radiochemotherapy for rectal cancer: Long-term results of the German CAO/ARO/AIO-94 phase III trial

Introduction: The CAO/ARO/AIO-94 phase-III-trial demonstrated a significant improvement of preoperative chemoradiotherapy (CRT) versus postoperative CRT on local control for UICC stage II/III rectal cancer patients, but no effect on long-term survival. In this add-on evaluation, we investigated the association of gender and age with acute toxicity and outcome. Patients and methods: According to actual treatment analyses, 654 of 799 patients had received pre-(n = 406) or postoperative CRT (n = 248); in 145 patients postoperative CRT was not applied. Gender, age and clinicopathological parameters were correlated with CRT-associated acute toxicity and survival. Results: The 10-year survival was higher in women than in men, with 72.4% versus 65.6% for time to recurrence (p = 0.088) and 62.7% versus 58.4% for overall-survival (OS) (p = 0.066), as expected. For patients receiving CRT, women showed higher hematologic (p < 0.001) and acute organ toxicity (p < 0.001) in the entire cohort as well as in subgroup analyses according to pre- (p = 0.016) and postoperative CRT (p < 0.001). Lowest OS was seen in patients without acute toxicity (p = 0.0271). Multivariate analyses for OS showed that acute organ toxicity (p = 0.034) was beneficial while age (p < 0.001) was associated with worse OS. Discussion: Female gender is significantly associated with CRT-induced acute toxicity in rectal cancer. Acute toxicity during CRT may be associated with improved long-term outcome. (C) 2013 Elsevier Ireland Ltd. All rights reserved.