[Volume and spatial representation of tumors in the core of the prostate gland].

OBJECTIVES

To describe a method of calculation of prostatic tumour volume allowing spatial representation of the tumour within the prostate gland.

METHODS

60 radical prostatectomy specimens were studied. Each specimen was processed according to the Stanford technique, and each prostatic section was also divided into two parts, anterior and posterior, according to a sagittal plane through the urethra. 5 microns thick serial sections were performed every 3 mm. The tumour surface area was calculated under light microscopy on each slide. The tumour volume between two consecutive slides was considered to be the volume of a truncated cone. The overall volume obtained was then equal to the sum of these various partial volumes. Spatial representation was performed according to two axes for each of the anterior and posterior parts of the prostatic sections: x-axis represented the prostate from the base to the apex, and the y-axis represented the tumour surface area in each prostatic section.

RESULTS

The tumour volume ranged from 0.01 cm3, from 0.21 cm3 for pT2A to 1.98 cm3 for pT3C. pT3 tumours corresponded to the largest volumes, but some pT3 had a small volume. pT3 tumours were preferentially located close to Denonvilliers fascia : 40% of posterior tumours were pT3 versus 9% of anterior tumours (p = 0.01).

CONCLUSION

The tumour volume on prostatectomy specimens can be evaluated by routine preparations and represents an additional element allowing better assessment of the TNM classification, as well as the predictive value of the information provided by prostatic biopsies.