Neo-adjuvant GnRH therapy and radical prostatectomy: effects on tumorous and benign tissue volumes - a morphometric...

The effect on tumour and prostate volumes of a 3-month course of neo-adjuvant hormone therapy was studied using computerised planimetry on serially sectioned specimens obtained by radical prostatectomy. Fifty-four specimens from patients not receiving pre-treatment were compared to 38 specimens from patients given the gonadotropin-releasing hormone (GnRH) analogue triptorelin for 3 months before the operation. Glandular volume and volume of the index tumour was determined. To determine the position of the index tumour within the gland, the centre of mass of the tumour was identified and the distance to the gland margin calculated. This value (M1) represents the sum of the tumour radius and the various amounts of normal tissue. The amount of surrounding tissue could be approximated by correlating M1 to the corresponding tumour volume.

The two groups differed significantly in total gland volumes, but not in tumour volumes. M1 was strongly correlated to the tumour volume in the treatment group (r = 0.73), whereas in the control group the correlation was found to be significantly weaker (r = 0.44), indicating that there was less tissue surrounding the tumour in the pre-treated group. In a multiple regression analysis of all 92 patients, index tumour volume was found to be associated with total gland volume, DNA ploidy pattern, tumour grade but not whether or not pre-treatment was given. This study found that the volumes of the single largest tumour focus were not significantly affected by hormonal pre-treatment, and that "the prostate condenses around the tumour rather than that the tumour shrinks back into the prostate". However, the precise relationship between tumour epithelial volume and stroma with or without neo-adjuvant hormonal pre-treatment remains to be clarified.