Salvage partial brachytherapy for prostate cancer recurrence after primary brachytherapy

Objectives To characterize local recurrence of prostate cancer and to assess the effect of salvage partial brachytherapy after primary 125-iodine low-dose rate brachytherapy with or without external beam radiotherapy in Japanese men. Methods Between 2003 and 2010, a total of 616 consecutive patients underwent low-dose rate brachytherapy-based therapy for clinically localized prostate cancer at Jikei University Hospital in Tokyo, Japan. Biochemical recurrence occurred in 45 (7.3%) patients at a median of 30months (range 11-93 months). A total of 20 patients subsequently underwent transperineal template prostatic biopsy; of those, eight had positive cores at the base of the prostate or at the seminal vesicles. These eight patients had underdosed areas identified at initial low-dose rate brachytherapy corresponding to the positive biopsy sites. All were confirmed to have only localized recurrence, and seven underwent salvage partial low-dose rate brachytherapy. Results Median prostate-specific antigen nadir level in the eight patients with biopsy-proven local recurrence after initial low-dose rate brachytherapy was 0.75ng/mL (range 0.39-2.06). The seven retreated patients tolerated the salvage partial low-dose rate brachytherapy well, and showed a decrease in prostate-specific antigen level at follow up. Two patients later developed biochemical and clinical progression at 11 and 13months, respectively. Prostate-specific antigen level continued to be low in the remaining five patients. No significant genitourinary or gastrointestinal toxicity was encountered. Conclusions Salvage partial low-dose rate brachytherapy for biopsy-proven localized prostate cancer recurrence appears rational, technically feasible and safe. Optimal patient selection is of utmost importance for long-term success. Larger studies with longer follow up are warranted.