IS ANASTOMOTIC BIOPSY NECESSARY BEFORE RADIOTHERAPY AFTER RADICAL PROSTATECTOMY?

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Abstract
External beam radiotherapy may be given after radical prostatectomy as adjuvant (immediate) or therapeutic (delayed) treatment, the latter in response to evidence of disease recurrence. In patients receiving delayed radiotherapy the necessity of a positive anastomotic biopsy before treatment remains unclear. We determined whether a positive anastomotic biopsy predicted the response to radiation in this setting. We reviewed the records of 67 patients who received radiotherapy for biochemical or biopsy proved recurrent prostate cancer after radical prostatectomy. Patients underwent surgery at our institution or its affiliated hospitals, or were referred to our institution for radiotherapy. All patients had a negative metastatic evaluation before receiving radiotherapy. Biochemical failure after radiotherapy was defined as serum prostate specific antigen (PSA) 0.2 ng./dl. or greater on 2 or more consecutive occasions. Biochemical recurrence-free survival was calculated using the Kaplan-Meier method. Independent predictors of PSA failure after radiotherapy were identified using the multivariate Cox proportional hazards model. Of the 67 patients evaluated 33 and 34 received radiotherapy for biochemical failure and biopsy proved local recurrence, respectively. The 3-year recurrence-free survival rate was 49% in patients treated for biochemical failure and 39% in those with biopsy proved local recurrence. There was no significant difference in PSA-free survival in these 2 groups. Only pre-radiotherapy PSA 1 ng./dl. or greater (p = 0.02) and seminal vesicle invasion (p = 0.02) were significant independent predictors of biochemical failure. A positive anastomotic biopsy did not predict an improved outcome after radiotherapy following radical prostatectomy. Anastomotic biopsy was associated with a longer time to salvage radiotherapy. However, this delay did not translate into worse disease-free outcomes in patients who underwent anastomotic biopsy. High pre-radiotherapy PSA greater than 1 ng./ml. was the most significant predictor of biochemical failure after therapeutic radiotherapy. Decisions regarding local radiation therapy after radical prostatectomy may be made without documenting recurrent local disease.