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.