PURPOSE: To analyse the rate of secondary malignancies observed in a series of 
675 prostate cancer patients who underwent a permanent implant brachytherapy 
between 1999 and 2003, and to compare the incidence with the expected rate in a 
matched general French population.
MATERIAL AND METHODS: The cohort included low-risk patients and a selection of 
"favourable-intermediate" risk patients. All patients were homogeneously treated 
using an intraoperative dynamic planning prostate brachytherapy technique, with 
loose 125-iodine seeds and a prescription dose of 145Gy. The mean follow-up was 
132 months.
RESULTS: The 10-year overall survival for the entire cohort was 92% (95% 
confidence interval [CI]: 90-94). The 10-year relapse-free survival rate was 82% 
(95% CI: 79-85). Overall, 61 second cancers were registered. When comparing with 
a matched general French population, the standard incidence ratio (SIR) for 
bladder cancer was 1.02 (95% CI: 0.46-1.93). For colorectal cancer, the SIR was 
0.45 (95% CI: 0.19-0.89). For lung cancer, the SIR was 0.38 (95% CI: 0.17-0.76). 
The SIR for all cancers was 0.61 (95% CI: 0.47-0.79). When excluding secondary 
colorectal and lung cancers (both with low SIRs in this series), the SIR for all 
cancers was 1.06 (95% CI: 0.77-1.29).
CONCLUSION: With a mean follow-up of more than 11 years, this series does not 
detect any excess risk of second cancers associated with permanent implant 
prostate brachytherapy. However, due to power limitation, a small increase in 
the risk of secondary malignancies cannot be totally ruled out.