Modern prostate brachytherapy. Prostate specific antigen results in 219 patients with up to 12 years of observed follow-up.

BACKGROUND

The purported lack of long term modern prostate brachytherapy outcome data continues to lead many physicians to recommend other, more traditional treatments. This concern for long term results has encouraged the authors to supplement their earlier 10-year follow-up of patients receiving brachytherapy; in the process, an additional 77 patients (> 50%) were added to the original cohort, and the follow-up time was increased by 2 years.

METHODS

Between January 1987 and September 1989, 229 patients with T1-T3 prostate carcinoma underwent transperineal prostate brachytherapy using iodine-125 (I-125). No patient received adjuvant hormone therapy. The median Gleason sum was 5 (range, 2-10). Of these patients, 147 were determined to have a high probability of organ-confined disease and were treated solely with an I-125 implant. The remaining 82 patients were determined to be at increased risk for extracapsular disease and received pelvic external beam radiation in addition to brachytherapy. All patients were followed continuously. Failure was defined as a positive biopsy, radiographic evidence of metastases, or three consecutive rises in prostate specific antigen (PSA) levels as defined by the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus article.

RESULTS

Excluding deaths from intercurrent disease, the median follow-up was 122 months (range, 18-144 months). Fourteen patients were excluded from analysis due to insufficient follow-up. Adopting the ASTRO definition of failure resulted in minimal change in survival when compared with the authors' previous study, which used a PSA level > 0.5 ng/mL as the failure point. Observed 10-year disease free survival (DFS) for the entire cohort was 70%. In the brachytherapy only group, the observed 10-year DFS was 66%, whereas those patients treated with the addition of external pelvic radiation achieved a DFS of 79%. None of the patients who were followed for the full 12 years failed between Years 10 and 12. Only 25% of the failures observed occurred > 5 years after treatment, thus confirming the durability of brachytherapy.

CONCLUSIONS

Prostate brachytherapy provides excellent long term disease control with few late failures reported in the authors' program. The addition of external beam radiation appears to confer survival advantages in selected patients. Using the ASTRO failure criteria for long term follow-up resulted in no significant difference compared with using a PSA failure point of 0.5 ng/mL.