Is anastomotic biopsy necessary before radiotherapy after radical prostatectomy?

Purpose: External beam radiotherapy may be given after radical prostatectom y 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 treatmen t remains unclear. We determined whether a positive anastomotic biopsy pred icted the response to radiation in this setting. Materials and Methods: We reviewed the records of 67 patients who received radiotherapy for biochemical or biopsy proved recurrent prostate cancer aft er radical prostatectomy. Patients underwent surgery at our institution or its affiliated hospitals, or were referred to our institution for radiother apy. All patients had a negative metastatic evaluation before receiving rad iotherapy. Biochemical failure after radiotherapy was defined as serum pros tate specific antigen (PSA) 0.2 ng./dl. or greater on 2 or more consecutive occasions. Biochemical recurrence-free survival was calculated using the K aplan-Meier method. Independent predictors of PSA failure after radiotherap y were identified using the multivariate Cox proportional hazards model. Results: Of the 67 patients evaluated 33 and 34 received radiotherapy for b iochemical failure and biopsy proved local recurrence, respectively. The S- year recurrence-free survival rate was 49% in patients treated for biochemi cal 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 invas ion (p = 0.02) were significant independent predictors of biochemical failu re. Conclusions: A positive anastomotic biopsy did not predict an improved outc ome after radiotherapy following radical prostatectomy. Anastomotic biopsy was associated with a longer time to salvage radiotherapy. However, this de lay did not translate into worse disease-free outcomes in patients who unde rwent 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 pr ostatectomy may be made without documenting recurrent local disease.