Morphometric studies of intra-prostatic volume relationships in localized prostatic cancer

To further characterize patterns of tumour growth and the distribution of markers for the aggressiveness of prostate cancer by assessing the relationships among the volume of the 'index' tumour and that of the remaining foci, with pathological (pT) stage, histological grade and DNA ploidy, and with the amount of low- and high-grade prostatic intraepithelial neoplasia (PIN).

Eighty-eight step-sectioned total prostatectomy specimens were analysed. The Gleason score, tumour stage and DNA ploidy (by flow cytometry) of multiple samples were determined. Tumour and PIN areas were outlined and their volumes estimated by computerized planimetry.

The pT stage, Gleason sum and DNA nondiploidy increased, and PIN volumes decreased, with increasing volume of the index tumour focus (P < 0.01), but did not differ significantly between uni- and multifocal tumours. However, PIN volumes were significantly larger in multifocal cases with an index tumour volume of > 3 mL than in unifocal tumours > 3 mL (P < 0.05). Small volume, unifocal tumours had little PIN. The most malignant features of each case were always represented in the index tumour but not generally in the remaining foci.

The volume distribution, related to multicentricity and its concomitant PIN volumes, indicates that large index tumours, uni- or multifocal, of medium or high grade, are associated with low PIN volumes. However, multifocal medium- and high-grade tumours with small index tumour volumes have higher PIN volumes. Small, single tumours are of low-grade and may represent the slowly progressing cancers possibly resembling those found in autopsy studies.