Background and purpose: To analyze the treatment results of transperineal (125)Iodine seeds in localized prostate cancer.
Patients and methods: Between 1985 and 1996, 102 patients with T1-T2 N0 prostate cancer were treated with transperineal (125)Iodine seed implants at the Academic Medical Centre in Amsterdam. Tumours were classified as T1c in four patients, T2a in 73 patients and T2b in 25 patients. The mean pre-treatment PSA was 17 ng/ml. The (125)Iodine seeds were implanted transperineally under transrectal ultrasound guidance. The mean prostate volume was 31 ml (range 15-48 ml). An average of 49 seeds (range 29-74) was implanted. The dose to the periphery of the prostate was 160 Gy. Until 1988, 27 patients had additional external pelvic irradiation to a dose of 40 Gy in 20 daily fractions of 2 Gy.
Results: The 5- and 7-year actuarial survival rates were 77 and 63%, respectively (median 102 months). Ten patients (9.5%) died from prostate cancer. The 5- and 7-year clinical progression rates were 12 and 17%, respectively. Biochemical failure rates at 5 and 7 years were 39 and 44%, respectively. Age, alkaline phosphatase, creatinine, differentiation grade, additional treatment, staging procedure, number of seeds, prostate volume, treatment period and PSA were analyzed as prognostic factors. Only pre-treatment PSA was a prognosticator of clinical and biochemical outcome but not of survival. Biochemical control at 6 years varied from 30% for pre-treatment PSA values higher than 20 ng/ml to 95% for values < or =8 ng/ml. Forty-one out of 49 patients who were sexually active before brachytherapy maintained sexual function during the follow-up. Complete urinary incontinence occurred in one patient. No rectal complications were seen in patients receiving brachytherapy alone.
Conclusions: Transperineal (125)Iodine seeds brachytherapy in localized prostate cancer achieves a good clinical control and overall survival with acceptable late toxicity. Biochemical failure was strongly correlated to the pre-treatment PSA value.