[en] Rationale: To assess the likelihood of men clinically free from adenocarcinoma 10 years after radiation therapy, remaining so through the second decade. Method: A retrospective analysis was performed on 33 men clinically disease free 10 or more years after radiation therapy with no androgen suppression. A median follow-up of a further 46 months beyond 10 years was available for this group. Kaplan-Meier actuarial analysis of outcome was used. Biochemical failure was defined as 2 successive PSA rises. Results: Of these 33 men, 17 originally had Gleason Grade 1-2 tumors, 9 Gleason 3, and 7 Gleason 4-5. In 28, serum PSA was available at 10 years. For 13, it was below 0.5 ng/ml; for 5, 0.5-1.0 ng/ml; for 3, 1.1-2.0 ng/ml; for 2, 2.1-4.0 ng/ml; for 6, >4.0 ng/ml. Four of the 8 patients with serum PSA values greater than 2, had had rising profiles prior to 10 years and had thus biochemically failed. They were excluded from further analysis. Subsequent clinical and biochemical disease free survival at 15 years respectively for the whole group was 83% and 54%, respectively. For those with a serum PSA at 10 years below 1 ng/ml, the corresponding figures were 89% and 69%. For those with a serum PSA greater than 1 ng/ml, they were 75% and 32%. Conclusions: A significant rate (31%) of biochemical failure was observed in the second decade after radiation therapy, although clinical failure was infrequently seen. The risk of subsequent biochemical failure was substantially lower for those with PSA values at 10 years of less than 1 ng/ml