Image-guided radiation therapy produces lower acute and chronic gastrointestinal and genitourinary toxicity in prostate cancer patients.

PURPOSE This paper compares individual radiation therapy techniques used for prostate cancer and their benefits in clinical practice. METHODS We retrospectively analyzed 921 patients with localized prostate tumors treated between 1997 and 2012. We divided the patients into four groups according to the selected treatment technique (conformal radiation therapy [3DCRT], intensity-modulated radiation therapy [IMRT], image-guided radiation therapy [IGRT], and volumetric-modulated arc therapy [VMAT]) and evaluated the incidence of acute and chronic gastrointestinal (GI) and genitourinary (GU) toxicity. RESULTS The incidence of grade 2 or greater acute GU and GI toxicity was significantly higher among techniques other than IGRT (p˂0.001). We found the same results in the case of grade 3 or greater acute GU toxicity (p˂0.001). Grade 3 or higher acute GI toxicity occurred only in one patient treated by 3DCRT. Cumulative late GI toxicity of grade 2 or higher and grade 3 or higher was recorded over 3 years significantly more frequently among non-IGRT techniques as compared to IGRT (p˂0.001). As regards GU toxicity, we found significantly higher incidence only for grade 2 or higher (p˂0.001), not for grade 3 or higher. No occurrence of grade 4 toxicity was recorded. The greatest incidence of patients without acute and chronic GI/GU toxicity was recorded in connection with VMAT. CONCLUSION IGRT demonstrated a pronounced reduction in acute and chronic GU and GI toxicity as compared to non-IGRT techniques in the treatment of localized prostate cancer.