Comparison of late gastrointestinal and genitourinary toxicity of prostate cancer patients undergoing intensity-modulated versus conventional radiotherapy using localized fields.

To compare late genitourinary (GU) and gastrointestinal (GI) toxicity of radiotherapy (RT) to localized fields for prostate cancer delivered using intensity-modulated RT (IMRT) versus conventional RT (ConvRT). The records of 461 patients were reviewed; 355 patients received IMRT and 106 received ConvRT. Late GU and GI toxicity were compared. Late GU toxicity rates were not significantly different (P=0.166); however, late GI toxicity rates were lower with IMRT (P=0.001). Regression analyses demonstrated that only IMRT use (P=0.006) predicted reduction in late GI toxicity but no factors correlated with late GU toxicity. IMRT did not influence late GU toxicity but was associated with a reduction of late GI toxicity over ConvRT.