In men treated with primary radiation for prostate cancer, serious genitourinary (GU) toxicities are a lasting phenomenon, researchers say.
"Our study shows that the increased risk of severe (Grade 3 or 4) GU toxicity attributable to radiotherapy persists beyond 10 years after treatment," Dr Grace Lu-Yao said. "Patients should weigh the potential benefit and risks before making treatment decisions."
In a November 19th online paper in the Journal of Urology, Dr Lu-Yao of The Cancer Institute of New Jersey in New Brunswick and colleagues point out, "A patient would undoubtedly be more inclined to receive radiation therapy if most toxicity were limited to the first few years after radiation, as opposed to persisting for the remainder of his life."
How the research was done
Their conclusions are drawn from Medicare data from 1992 to 2007 on 60 134 men who received radiation therapy for T1-T2 prostate cancers and a further 25 904 who underwent observation. The mean age was 66 to 85 years, and the median follow-up was close to eight years.
Toxicities were broadly categorised as GU obstruction/stricture, cystitis, fistula and incontinence.
Compared to the observation group, the adjusted risk ratio for genitourinary toxicity was 2.49 at 10 years and beyond in the intervention group. The most common toxicities were obstruction/stricture and cystitis.
Men who had procedures for obstruction or stricture before radiation therapy were at significantly increased risk of GU toxicity (risk ratio 2.78).
The investigators acknowledge the study's limitations, including the fact that it was restricted to elderly patients, but still, they say, it is the "first large-scale population based study demonstrating that the time course of severe GU toxicity after prostate radiation is persistent and the increased risk lasts more than 10 years."
(Reuters Health, November 2012)