Dattoli M et al. (2007) Long-term prostate cancer control using palladium-103 brachytherapy and external beam radiotherapy in patients with a high likelihood of extracapsular cancer extension. Urology 69: 334–337

Prostate brachytherapy is widely used to treat patients with low-risk prostate cancer, but its use in patients at high risk of extracapsular cancer extension (ECE) is controversial. Dattoli and colleagues investigated the long-term biochemical control rates when external beam radiotherapy (EBRT) and palladium-103-labelled (103Pd) brachytherapy were used in combination between 1992 and 1996 to treat 243 consecutive patients (median age 66 years, range 43–88 years) who had at least one high-risk factor for ECE.

Participants were eligible if they had ≥1 of the following risk factors: Gleason score ≥7; serum PSA level >10 ng/ml; or prostatic acid phosphatase level >2.5 U. Patients received 41 Gy EBRT, followed by a 103Pd boost 4 weeks later. Follow-up was scheduled at 3, 6 and 12 months, then every 6–12 months thereafter. The researchers defined freedom from biochemical failure as serum PSA ≤0.2 ng/ml at last follow-up visit.

More than 5 years' follow-up was achieved in 198 patients (median 9 years, range 1–13 years). At 13 years' follow-up, the overall freedom from biochemical failure rate was 81%; 41 patients experienced failure. The absolute risk of biochemical failure decreased over time to 1% after 6 years. Of all failures, 27 occurred within the first 3 years after treatment. The strongest predictor of failure was prostatic acid phosphatase level.

The authors conclude that the high tumor control rates achieved by brachytherapy, in combination with EBRT, has useful and durable effects for patients with prostate cancer at high risk of ECE.