DNA image cytometry of prostatic carcinoma: a comparison of needle core biopsy and subsequent prostatectomy specimens

DNA ploidy has recently been identified as an objective prognostic factor in prostatic carcinoma. Although the diagnosis of prostatic carcinoma is increasingly being made with the use of needle core biopsies, the optimal method for the cytometric analysis of these specimens has yet to be determined. In addition, the degree to which the biopsy is representative of the subsequent prostatectomy specimen with respect to DNA heterogeneity has not been adequately addressed. In this study, image cytometric (ICM) DNA analysis was performed on tissue sections from 12 prostatic needle core biopsies and the results were compared with similar ICM analysis of the subsequent prostatectomy specimens. Multiple blocks (n = 48) of the prostatectomy specimens were utilized to prepare tissue sections and nuclear suspensions and each set of preparations were analyzed by ICM in a parallel comparison study. There was concordance of 0.80 in the classification of DNA diploid and aneuploid tumors by ICM analysis of tissue sections and nuclear suspensions from paraffin blocks. In all of the discordant cases, DNA aneuploid populations were identified by ICM analysis of tissue sections only. This is attributed to difficulties in obtaining a representative nuclear suspension from disaggregated paraffin-embedded prostatic tissue which often has a very desmoplastic stroma. ICM analysis of tissue sections seems to be an optimal method for DNA ploidy analysis of prostatic carcinoma and is well suited to small volume biopsy material. Determination of DNA ploidy status in prostatic biopsies was predictive of the subsequent prostatectomy specimens with a concordance of 0.92.