Radiotherapy for prostate cancer is associated with an increased incidence of secondary bladder cancer (BC). We investigated the incidence, clinicopathological characteristics, and prognosis of BC after radiotherapy, surgical therapy, and primary androgen-deprivation therapy (ADT) for prostate cancer. This study included 1,334 Japanese patients with prostate cancer treated with radiotherapy (n=631), surgical therapy (n=437), and primary ADT (n=266). During the median follow-up period of 51.2, 44.8, and 45.5 months, secondary BC occurred in 14 (2.2%), 5 (1.1%), and 0 (0%) of patients with prostate cancer treated with radiotherapy, surgical therapy, and primary ADT, respectively. The 10-year BC-free survival rate was 91.3% in the radiotherapy group, 97.4% in the surgical therapy group, and 100% in the primary ADT group. The rates of intravesical recurrence, progression to muscle-invasive BC, and BC-specific death might be higher in secondary BC after radiotherapy compared with after surgical therapy. There was a significant difference in the incidence of secondary BC among different therapeutic modalities for prostate cancer in Japanese men, indicating significantly lower comorbidity rates of secondary BC after primary ADT for prostate cancer compared with radiotherapy.
Keywords: androgen-deprivation therapy; bladder cancer; prostate cancer; radical prostatectomy; radiotherapy.