GI toxicity is reported for both RT and brachytherapy. This study used the SEER database to assess long-term GI toxicity from RT.
The final study cohort included 28,088 men ages 66-85 diagnosed with clinically localized CaP between 1992 and 2005. The control group consisted of 13,649 men conservatively managed for their CaP who had no intervention for at least one year after diagnosis. RT was considered external beam radiotherapy, brachytherapy, or a combination of both modalities. External beam radiotherapy was further categorized into 3-D conformal (CRT), intensity-modulated (IMRT), or proton beam therapy. The focus of toxicity was grade 3 or 4 that required intervention and could be identified by using ICD-9 or CPT codes. Only toxicities that occurred 6 or more months after treatment were counted. Hazard ratios (HRs) were obtained between RT and conservative management. They also assessed 20,114 men who survived at least 5 years after diagnosis and were still free of GI toxicities at the 5-yr point and compared the GI toxicity rate using a competing risk model.
Conservatively managed men had greater comorbidity, were older, and more likely to reside in a low-income area. They also had less aggressive tumors. The RT patients were treated with EBRT in 19,063, brachytherapy in 5,338, and EBRT and brachytherapy in 3,687. There was greater GI toxicity in external beam RT patients (8.8 per 1,000 person-years) compared with brachytherapy (5.3 per 1,000 person-years). Conservative management had GI toxicity in 2.1 per 1,000 person-years. Interestingly, per 1,000 person years proton-beam therapy had the greatest toxicity (20.1), followed by 3D CRT (9.3), and IMRT (8.9). Ulceration was the most common late GI toxicity. The 10-year GI toxicity rate was 1.5% for conservatively managed men and 5.8% for RT. Proton beam therapy had the highest rate of GI toxicity and IMRT and brachytherapy the lowest. The risk of late GI toxicity was most associated with RT (4.74). There was a continued risk of new GI toxicity beyond 5-years in patients treated with RT compared to the conservatively managed group.
Kim S, Shen S, Moore DF, Shih W, Lin Y, Li H, Dolan M, Shao YH, Lu-Yao GL
Eur Urol. 2011 Nov;60(5):908-16.
10.1016/j.eururo.2011.05.052
PubMed Abstract
PMID: 21684064
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