OBJECTIVES: The life expectancy of candidates for attempted curative therapy of prostate cancer should not be inferior to 10 yr. We examined the rate of 10-yr survival in septa- and octogenarians treated for prostate cancer with either attempted curative external beam radiotherapy (EBRT) or radical prostatectomy (RP). METHODS: Within a population-based cohort of 17,570 EBRT or RP patients, 6183 men aged 70 yr or older were treated with either RP (n=1591) or EBRT (n=4592) and represented the focus of crude survival analyses. Age and Charlson Comorbidity Index represented covariates. To control for prostate cancer-specific mortality, we repeated the analyses in a subset of 2704 men (RP, n=881; EBRT, n=1823) who had no clinical evidence of disease relapse of prostate cancer. RESULTS: Overall actuarial 10-yr survival was 38.5% (RP 59.3% vs. EBRT 30.3%, p