Bladder cancer incidence and mortality in patients treated with radiation for uterine cancer.

Abstract

To estimate the effect of radiation therapy (RT) administered for uterine cancer (UtC) on bladder cancer (BC) incidence, tumour characteristics at presentation, and mortality. In this retrospective cohort study, records of 56 681 patients diagnosed with UtC as their first primary malignancy during 1980-2005 were obtained from the Surveillance, Epidemiology and End-Results (SEER) database. Follow-up for incident BC ended on 31 December 2008. Occurrences of BC diagnoses and BC deaths in patients with UtC managed with or without RT were summarised with counts and person-time incidence rates (counts divided by person-years of observation). Age adjustment of rates was performed by direct standardisation. Incident BC cases were described in terms of histological types, grades and stages. With a mean follow-up of 15 years, BC was diagnosed in 146 (0.93%) of 15 726 patients with UtC managed with RT, and in 197 (0.48%) of 40 955 patients with UtC managed without RT, with an age-adjusted rate ratio of 2.0 (95% confidence interval [CI] 1.6-2.5). Fatal BC occurred in 39 (0.25%) and 36 (0.09%) of patients with UtC managed with vs without RT, respectively, with an age-adjusted rate ratio of 2.9 (95% CI 1.8-4.6). Incident BC cases diagnosed in patients with UtC managed with vs without RT had similar distributions of histological types, grades, and stages. Use of RT for UtC is associated with increased BC incidence and mortality later in life. Heightened awareness should help identify women with new voiding symptoms or haematuria, all of which should be fully evaluated.