[Relation between prostate gland volume and some histological markers of malignancy]

The relationship between the total volume of the prostate gland or its weight after radical prostatectomy and the histological markers of malignancy in cases of prostate cancer is a controversial subject. We have analyzed 100 consecutive radical prostatectomy specimens in order to determine the relationship between volume or weight of the prostate gland and the biological aggressiveness of the tumor process by different histological markers.

One hundred consecutive radical prostatectomy specimens in patients who had not received pre-operative hormone treatment were retrospectively reviewed. These surgical samples were processed according to a standardized protocol. In a subsequent evaluation, the following were studied with greater detail: Gleason grade, tumor volume, multimodality, neural or vascular invasion, put stage, and presence of PIN foci. The histological findings were compared with the prostate gland weight using Windows SPAS, 13.0 statistical package with a significance value of p<0.05. According to the prostate gland weight, three groups were established: <40 g (33%), 40 - 90 g (61%), and >90 g (6%).

A statistically significant association (p=0.001) was found between the prostate gland weight and tumor volume since 15 of the 33 glands with weight under 40 g accounted for more than 50% of the glands affected by tumor compared to none of the 6 patients with total weight over 90 g. A significant relationship was also found between the multimodality and weight. (P=0.03), so that 24 of the 33 glands under 40 g had bilateral multimodality compared to only 1 out of the 6 glands over 90 g. The neural invasion, number of PIN foci and the highest combined Gleason grade were frequent in low volume prostates, but the difference did not reach statistical significance.

Our study indicates that large volume prostate glands have tumors with lower malignancy (tumor volume, bilateralism). This finding justifies the adequacy of using total volume of the prostate gland for diagnostic decision (indication of prostatic biopsy and their repetition) and the prognostic determination.