Quantitative and qualitative AgNORs rates of prostate cancer on needle core biopsies: a multicentric study

From 1992 to 1993, the Scarpa Foundation Center of Pavia (SFCP) with 12 associated Italian Urological Units selected 40 cases of prostate diseases discovered on needle core biopsies, 5 of which were benign hyperplasias (BPH) in patients without clinical and morphological evidence of cancer and 35 prostate cancers (PRC) classified according to Gleason's histological grades (GLG) of PRC malignancy. Serum prostatic specific antigen (PSA) values were tested before clinical urological examination or biopsy or surgery. In all groups, AgNORs scores/nucleus were obtained by semi- and -automatic computerized image analysis and also by qualitative subjective counts of three observers on light microscopy. Our results pointed out a good correlation between PSA levels, GLG of PRC malignancy and AgNORs scores. The quantitative method showed an average number of AgNORS dots per nucleus between 2 and 3 in well differentiated PRC and higher than 3 in moderately differentiated and undifferentiated PRC, and exhibited more sensitivity over GLG3 than the qualitative investigation. The qualitative subjective count of AgNORs dots/nucleus seemed to be more reliable in differentiating the AgNORs scores of BPH (average of 1.81 dots/nucleus) from very well differentiated PRC with GLG1 + 2(average of 2.25 dots/nucleus) than quantitative analysis, which showed the same average value in both groups (2.11 dots/nucleus). For these reasons, also on needle biopsies of benign and malignant prostate diseases the subjective AgNORs count may aid the histological diagnostic judgement of malignancy, by avoiding misleading diagnoses of microscopic pictures of BPH cancer look likes and a predictive histologic malignant factor, in identifying PRC with low or high progression.