NUCLEAR DEOXYRIBONUCLEIC-ACID PLOIDY AND SERUM PROSTATE SPECIFIC ANTIGEN IN OPERABLE PROSTATIC ADENOCARCINOMA

A total of 71 patients with prostate carcinoma who underwent radical retropubic prostatectomy had preoperative measurement of serum prostate specific antigen levels and subsequent nuclear deoxyribonucleic acid ploidy analysis of the resected tumors. Prostate specific antigen levels were determined by a commercially available prostate specific antigen radioimmunometric assay (normal range 0 to 4.0 ng./ml.). The paraffin-embedded blocks of the prostate specimens were analyzed by flow cytometry for nuclear deoxyribonucleic acid content using Hedley's technique and propidium iodide staining. A strong association was found between nuclear deoxyribonucleic acid ploidy patterns and preoperative prostate specific antigen values. All patients with tetraploid and aneuploid tumors had elevated preoperative prostate specific antigen values. By contrast, all patients with preoperative antigen values of less than 4 ng./ml. had diploid tumors (p < 0.0034). Prostate specific antigen levels were proportional to the estimated volume of the primary tumor (p < 0.0065). However, even after statistical adjustment for tumor volume the preoperative prostate specific antigen value was still significantly and independently correlated with deoxyribonucleic acid ploidy pattern (p < 0.007). However, only 35% of the patients with diploid tumors had antigen levels within the normal range. Conversely, 65% of the patients with diploid neoplasms had abnormally high antigen levels preoperatively. These results suggest that patients with localized biopsy proved prostate carcinoma and normal preoperative prostate specific antigen values are most likely to have dipolid tumors; based on a 95% confidence level, the true proportion of patients with normal prostate specific antigen values who also have a deoxyribonucleic acid diploid tumor is 85 to 100%. Since localized deoxyribonucleic acid diploid tumors are known to be associated with a favorable prognosis for patients with prostate carcinoma treated by radical prostatectomy, a preoperative serum prostate specific antigen level within the normal range may help to predict disease outcome.