Factors predicting cancer detection in biopsy of the prostatic fossa after radical prostatectomy

Objectives. To determine whether the results of anastomotic biopsy for prostate-specific antigen (PSA) recurrence after radical prostatectomy could be predicted by either PSA, PSA velocity, digital rectal examination (DRE), transrectal ultrasound (TRUS), or the interval from prostatectomy to biopsy. Methods. TRUS with biopsy of the anastomosis was performed for 91 postprostatectomy patients who had either an abnormal DRE or detectable PSA (greater than 0.2 ng/mL). The biopsy results were correlated with the findings of DRE, TRUS, PSA, PSA velocity, interval to PSA recurrence, and with the pathologic stage. Results. Of 131 examinations, there were 50 positive biopsy specimens for a detection rate of 38%. Of 34 patients with PSA 1.0 ng/mL or less, 8 (24%) had positive biopsy ( P = 0.02). A negative DRE lowered (but did not eliminate) the probability of a positive biopsy. Of 100 patients with normal DRE, 28 (28%) had positive biopsy. None of the 11 patients with a negative DRE and a PSA of 0.5 ng/mL or less had a positive biopsy ( P = 0.02). The mean interval between prostatectomy and biopsy was significantly greater in patients who had a positive biopsy (45 ± 39) than in patients with a negative biopsy (27 ± 21) ( P = 0.001). The pathologic stage, Gleason score, and PSA velocity were not helpful in predicting the results of biopsy. Conclusions. Although patients with a negative DRE can have a positive biopsy and patients with a PSA of 1.0 ng/mL or less can have a positive biopsy, no patient with a negative DRE and a PSA of 0.5 ng/mL or less has a positive biopsy.