No residual cancer on radical prostatectomy after positive 10-core biopsy: incidence, biopsy findings, and DNA specimen identity analysis.

CONTEXT: It is uncertain whether extensive prostate-specific antigen (PSA) testing and extended biopsies currently performed will increase the incidence of no residual cancer on subsequent prostatectomy.
OBJECTIVE: To identify the incidence of cases with no residual cancer on prostatectomy after a positive 10-core biopsy and to review the clinical, biopsy, and prostatectomy findings and the results of specimen identity analysis.
DESIGN: We identified 9 patients with no residual cancer in 1351 consecutive prostatectomies and we reviewed the clinical, biopsy, and prostatectomy data from our institutional database. In 6 cases encountered after 2003, we also performed a polymerase chain reaction-based microsatellite analysis on formalin-fixed tissue to confirm the identity of the biopsies and prostatectomies.
RESULTS: All patients had positive biopsies in 1 or 2 cores: 1 in 7 and 2 in 2 patients (1 each, unilateral and bilateral). Mean total cancer length on biopsy measured 2.5 mm, which represented 1.7% of the total biopsy tissue. Gleason score 6 was found in 8 of 9 patients and 1 patient had Gleason score 9. Patients' age was 60.3 years, preoperative PSA was 6.0 ng/mL, and PSA density was 0.1 (all means). In 6 cases tested for microsatellite identity, the patient identity was confirmed.
CONCLUSIONS: Incidence of no residual cancer on prostatectomy of 0.67% after 10-core positive biopsy is higher than previously reported. In most cases, finding no residual cancer on prostatectomy after exhaustive work-up may indicate minimal patient disease. Microsatellite analysis provides a useful and cost-effective test in establishing specimen identity.