Risk of bladder cancer following external beam radiation for prostate cancer

Abstract

Abstract Introduction: Increased rates of secondary malignancies of the bladder have been reported after external beam radiation therapy (EBRT) for gynecologic malignancies with relative risks varying from 3–57. This study will determine if there is increased risk of subsequent bladder cancer for men treated with EBRT for prostate cancer from 1970–1999. Methods: We retrospectively reviewed the Mayo Clinic Cancer Registry for patients who received EBRT for prostate cancer, and isolated a cohort of patients with 10,000 man-years of follow-up after radiation. Medical histories of patients who developed subsequent bladder cancer were reviewed. Comparative cancer incidence rates were obtained from the SEER database (2000). Results: Of 3700 patients treated with EBRT for prostate cancer from 1970–1999, 806 patients (with 10,002 follow-up years) were randomly selected. 26 developed a subsequent bladder cancer. 20 sporadic cases of TCC were expected in a similarly aged population without radiation (from SEER data). Our data demonstrates the relative risk of developing a subsequent bladder cancer is 1.3 (CI 0.85–1.91) which is elevated but not statistically significant. Conclusions: This retrospective review shows the risk of bladder cancer in men who received radiation for prostate cancer is slightly higher than expected in a non-irradiated population. It is, however, lower than the risk reported in the gynecologic literature. Both radiation cystitis and bladder tumors can present with hematuria and irritative voiding. Urologists should be vigilant in evaluation of this subset of patients at increased risk for vesical neoplasms.