[Prostate cancer: comparative study of stage T1a and stage T1b].

Objective: To compare the epidemiological profiles and histoprognostic factors of two groups of prostate cancer: T1a versus T1b.

Materials And Methods: Between January 1996 and December 2005, 1359 patients were operated for benign prostatic hyperplasia (BPH) in our urology department. All patients had a PSA less than 4 ng/ml, an adenomatous prostate on digital rectal examination with a homogeneous appearance on prostatic ultrasonography. The population of patients with prostate cancer was classified into group 1 (stage T1a) and group 2 (stage T1b). The following parameters were studied: age at diagnosis, PSA, volume of prostatic tissue removed (by resection or enucleation), histological findings.

Results: In this series of 1359 operated patients (762 by endoscopic resection and 597 by transvesicalprostatectomy), 44 (3.23%) had prostate cancer Group 1 comprised 18 patients (40.9%) and group 2 comprised of 26 patients (59.1%). Group 1 had a mean age of 74.7 years, a mean PSA of 2.36 ng/ml and a mean prostatic volume of 37.16 ml. Corresponding values for group 2 were 74.4 years, 3.11 ng/ml and 26.3 ml, respectively The Gleason score was low (2-4 and 5-6) and no grade 4 was observed for any of the patients of group 1, while 50% of patients of group 2 had a high Gleason score (7-10).

Conclusion: The incidence of stage T1a and T1b prostate cancer is low due to the increasingly systematic use of PSA. The volume of the prostate and transitional zone does not influence the stage T1a and T1b prostate cancer detection rate. T1b cancer has a poorer prognosis than stage T1a cancer.