Deoxyribonucleic acid cytometric analysis of prostate core biopsy specimens: relationship to serum prostate specific antigen and prostatic acid phosphatase, clinical stage and histopathology.

Abstract

We describe a sampling method of obtaining fresh prostate cells that yields adequate numbers of cells for flow cytometric deoxyribonucleic acid (DNA) analysis and produces histograms of good resolution. Exfoliated cells from 204 prostate biopsy wash specimens obtained by agitation of biopsy cores in saline were fixed and stained for DNA analysis. The mean percentage of hyperdiploid cells was statistically different between the pathologically benign and malignant specimens (p < 0.0001). Hyperdiploid cells of 22% or more exhibited a high degree of specificity for the malignant specimens with only a 1.4% (1 of 69 benign specimens) false-positive rate. However, sensitivity was only 41% (25 of 59 malignant specimens were associated with a flow cytometry analysis of 22% or greater hyperdiploid cells) because of the high false-negative rate (59%, 35 of 59). The percentage of hyperdiploid cells correlated statistically with increasing prostate specific antigen (PSA) levels and approached significance with Gleason grade but did not correlate with prostatic acid phosphatase or clinical stage. When the amount of hyperdiploid cells was 22% or more and serum PSA level was greater than 4.0 ng./ml. a 95% chance of a malignant biopsy was predicted. This result was greater than that predicted by a PSA elevation alone. Only a 5% chance of a malignant biopsy was present for patients with less than 22% hyperdiploid cells and 4.0 ng./ml. or less serum PSA, a decrease over either method separately. This method of DNA assessment permits prospective categorization of tumors by ploidy without interfering with histological assessment. The prognostic importance of ploidy analysis awaits further clinical followup.