Background: In low-risk prostate cancer, the target volume for radiotherapy is the prostate gland only and prostate brachytherapy with an I-125 implant provides the most conformal radiotherapy.
Methods: Patients underwent a pre-implant prostate volume study from which a treatment plan was developed 2 weeks prior to implant. A dosimetric study was performed 1 month following the implant. The prescription dose was 145 Gy with the 95% isodose line covering the entire target volume. The maximal dose to the urethra was less than 210 Gy. Follow-up included serum PSA and IPSS evaluation every 3 months during the first year and then every 6 months beginning in the second year.
Results: During December 2000–March 2009, 181 patients with early prostate cancer underwent I-125 implant. The median post-implant PSA value of the entire cohort was 0.7 ng/ml. No patient developed clinical failure. In the follow-up, nine patients had biochemical failure according to the RTOG-ASTRO Phoenix definition (Nadir + 2.0 ng/ml). Of these, one patient refused hormonal therapy desiring to preserve sexual potency, and eight patients received hormonal therapy with a decreased serum PSA to 0.0 ng/ml. The treatment side effects were primarily urinary disturbances.
Conclusion: An I-125 implant is an effective and well-tolerated treatment and should be recommended for patients with low-risk prostate cancer.