Objective: Small volume prostate cancers (<0.5 cc, svPC), and insignificant prostate cancers (<0.5 cc and Gleason scores <7, InsigPC) are considered clinically insignificant by some investigators. The aim of this study is to determine the biochemical recurrence rate (BCR) of svPC and InsigPC in prostatectomy specimens.
Methods: In total, 502 patients with prostate cancer, treated with radical prostatectomy (RP) between 1992 and 2005 and with detailed pathological classification, were included in the present study. Patients were postoperatively followed for a median period of 39.5 months (0.6-150). A total of 82 specimens (16.3%) with svPC including 64 (12.8%) with InsigPC were identified. BCR was defined as 2 consecutive PSA levels >0.10 ng/ml.
Results: In the total group, the median age at the time of surgery was 62.7 years (42.4-73.4) and the median preoperative PSA level was 8.0 ng/ml. Patients with InsigPC had Gleason scores of 4 in 7%, 5 in 37%, and 6 in 56%. Positive surgical margins were identified in 13 (15.9%) svPC and in 8 (12.7%) InsigPC specimens. The 5-year risk of BCR for the svPC group and the insigPC group was 10% (95% CI 2-18%, 7 and 5 patients, respectively) vs. 35% (95% CI 29-41%) in the rest of the cohort (log rank P = 0.001).
Conclusion: Patients with svPC and patients with InsigPC have a significantly lower risk of BCR. However, even in this seemingly very favorable patient group, 1 in 10 patients will develop a BCR after RP. Therefore, new studies are needed to examine what the prognostic relevance is of small-volume tumors.