Pathological features of Gleason score 6 prostate cancers in the low and intermediate range of prostate-specific antigen level: is there a difference?

OBJECTIVE: To assess the pathological features of Gleason score 6 prostate cancers after radical prostatectomy in the low (<4 ng/mL) and intermediate range of prostate-specific antigen level (4-10 ng/mL), as such prostate cancers are considered to be well differentiated tumours with a low risk for recurrence after therapy. PATIENTS AND METHODS: In all, 1354 patients with T1c prostate cancer and PSA levels of <10.0 ng/mL had a radical retropubic prostatectomy. Patients with Gleason score 6 tumours were divided into two groups, those with PSA levels of <4 and 4.0-10.0 ng/mL. Extracapsular extension, positive surgical margins, biochemical recurrence (BCR) and mean time to BCR were evaluated.
RESULTS: Of the 1354 patients, there were 437 (32.3%) with Gleason score 6 prostate cancers. Patients in the low PSA group had less extraprostatic disease than those with a higher level (5.9% vs 14.5%) and both groups had an almost equal proportion of positive surgical margins (9.4% vs 11.0%). In the low PSA group there was statistically significantly shorter BCR than in the high PSA group, with a mean time to BCR of 1.7 vs 3.1 years.
CONCLUSIONS: These results show a statistically significantly higher rate of extraprostatic disease and earlier BCR in men with a high than a low PSA level even in Gleason score 6 prostate cancer. As the rate of BCR and extracapsular extension are significantly related to prostate cancer mortality, these findings further support the concept of screening using low PSA levels.