External-beam radiation therapy for localized prostate cancer linked to other cancer

Patients undergoing external-beam radiation therapy (EBRT) for localized prostate cancer may be at an increased risk for secondary malignancy, according to a study from researchers in Canada, Italy and the United States presented today during the Annual Scientific Meeting of the American Urological Association (AUA) in Orlando. Researchers presented data to reporters during a special press conference on May 19, 2008 at 1:30 p.m. These findings have significant implications for men evaluating treatment options for localized prostate cancer.

Using records from 10,333 men treated for localized prostate cancer (6,196 with radical prostatectomy and 4,137 with EBRT) between 1983 and 2004, researchers examined subsequent diagnoses of bladder, lung and colorectal cancer to determine whether the incidence rate of these secondary malignancies was greater in patients who underwent EBRT as opposed to radical prostatectomy.

Researchers used diagnosis codes defining cystectomy, lobectomy or pneumectomy (for lung cancer) and colectomy (with or without rectal resection) for colorectal cancer to identify the incidence of secondary malignancy in this study population. 92 cystectomies, 82 lung cancer surgeries and 228 colorectal cancer surgeries were performed. Univariable analyses showed an increase in the rate of secondary malignancy treatment in men treated with EBRT. Multivariate analysis was performed, with adjustments made for age, baseline comorbidities and year of treatment – and indicated that EBRT predisposed patients to a 3.0-fold increase for cystectomy for bladder cancer, 1.8-fold rate of lung-cancer resections and 1.7-fold higher rate of rectal cancer.

Source: American Urological Association