IDENTIFICATION OF INSIGNIFICANT PROSTATE CANCERS - ANALYSIS OF PREOPERATIVE PARAMETERS

Objectives. Analyzing preoperative parameters to help determine the risk of a random or systematic prostate needle biopsy specimen detecting an incidental microscopic prostate cancer. Methods. We reviewed the charts of 28 patients who had less than or equal to 3 mm of Gleason grade (Glgr) less than or equal to 2 (score less than or equal to 4) prostate cancer in their prostate biopsy specimen and subsequently underwent a radical retropubic prostatectomy (RRP). Histopathologic review of the RRP specimen was carefully performed to determine the respective tumor volume, number of tumor foci, pathologic stage, Glgr, and score. Prostate-specific antigen (PSA) levels and the calculated PSA density (PSAD) were recorded for each case. Results. Sixteen of the 28 (57%) RRP specimens contained a very small well-differentiated tumor (less than or equal to 0.2 cc); 7 (25%) tumors were minimally larger (0.2 to 0.5 cc); and 2 specimens (7%) contained a large tumor (4 and 6 cc) only sampled by the biopsy specimen. Mean PSA levels and PSAD values both significantly differentiated tumors less than or equal to 0.5 cc from those > 0.5 cc (p < 0.005). PSA less than or equal to 4 vs PSAD less than or equal to 0.1 correctly identified 12 of 23 (52%) vs 22 of 25 (96%) tumors less than or equal to 0.5 cc, and 10 of 16 (63%) vs 15 of 16 (94%) tumors less than or equal to 0.2 cc, respectively; both parameters excluded 4 of 5 (80%) tumors >0.5 cc. PSA less than or equal to 4 vs PSAD less than or equal to 0.1 identified 13 of 25 (52%) vs 24 of 25 (96%) organ-confined tumors, respectively, and both parameters excluded the 2 specimen-confined and 1 margin-positive tumors. Thus, PSAD had an excellent ability to differentiate the tumors based on their volumes. All tumors less than or equal to 0.5 cc in the RRP specimen were organ-confined and postoperative serial PSA levels remained < 0.4 in these patients at a mean follow-up of 24 months. Conclusions. Our data indicate that a patient who has a random or systematic prostate biopsy specimen that contains less than or equal to 3 mm of Glgr less than or equal to 2 prostate cancer and a PSAD less than or equal to 0.1 is at a substantial risk (82%) of being diagnosed with an incidental, organ-confined, and probably insignificant, microscopic prostate cancer.