Second cancers in patients with locally advanced prostate cancer randomized to lifelong endocrine treatment with or without radical radiotherapy. Long term follow- up of the Scandinavian Prostate Cancer Group-7 trial.

Median follow-up of the 860 (431 ET and 429) ET+RT patients was 12.2 years for SC risk analysis and 12.6 years for the OS analysis. Eighty-three of the Norwegian ET patients received salvage RT, median time to salvage RT was 5.9 years We found 125 and 168 SCs in the ET and ET+RT patients, respectively. With ET alone as reference, ET+RT patients had a HR of 1.19 (95%CI 0.92-1.54) for all SCs and 2.54 (95 % CI 1.14-5.69) for urinary bladder cancer (UBC). The total number of UBC was 31 (23 in ET+RT/ 8 in ET), and the vast majority (85 %) were superficial. The HR for SC in salvage RT patients was 0.48 (95% CI 0.24-0.94). Median OS was 12.8 (95 % CI 11.8-13.8) and 15.3 (95% CI 14.3-16.4) years in the ET and ET+RT groups, respectively. Compared to ET alone, the risk of death was reduced in ET+RT patients (HR 0.73, 95% CI 0.62-0.86), and in ET patients receiving salvage RT (HR 0.44, 95% CI 0.30-0.65).