Long-term tumor control after brachytherapy for base-of-prostate cancer

Purpose: To evaluate the outcomes of patients presenting with cancer at the base of the prostate after brachytherapyas monotherapy. Material and methods: We retrospectively reviewed the medical records of all patients who had undergone transpe -ri neal ultrasound-guided implantation with 125I or 103Pd seeds as monotherapy between March 1998 and December2006, at our institution. A minimum follow-up interval of 2 years was required for inclusion in our analysis. Dosimetrywas assessed using computed tomography 30 days after the implant. Treatment failure was defined as the appearanceof biopsy-proved tumor after seed implantation, radiographic evidence of metastases, receipt of salvage therapy,or elevation of the prostate-specific antigen level beyond the nadir value plus 2 ng/mL. Results: With a median follow-up interval of 89 months (range 25-128 months), all 52 of the identified patients hadno evidence of disease progression or biochemical failure. The mean number of cores sampled at the prostate base was2.84 (median 2); Gleason scores assigned at central review were 6-8 in all patients. Of the 30 patients (58%) for whomdosimetric data were available at day 30, the median V100 values of the right and left base were 92.0% and 93.5%, respectively,and the median D90 values of the right and left base were 148 Gy and 151 Gy, respectively. Conclusion: Permanent prostate brachytherapy as monotherapy results in a high probability of disease-free survivalfor men with cancer at the base of the prostate.