Preoperative serum
prostate specific antigen correlates well with morphometrically determined prostate
tumor volume in
prostatectomy specimens. However, since
prostate specific antigen is produced by hyperplastic as well as malignant prostatic epithelium, the contribution of hyperplastic epithelium (
benign prostatic hyperplasia) to serum
prostate specific antigen interferes with the ability of serum
prostate specific antigen to predict
tumor volume in individual patients. We wondered if the removal of
benign prostatic hyperplasia tissue would increase the correlation between
prostate specific antigen and
tumor volume, and, thus, make
prostate specific antigen a more accurate predictor of
residual cancer volume after transurethral resection of the prostate. A total of 67 patients with clinical stage A
cancer underwent radical
retropubic prostatectomy (22, or 33%, with stage A1 and 45, or 67%, with stage A2 disease), and had pre-radical
prostatectomy measurement of serum
prostate specific antigen and morphometric determination of
residual cancer volume in the radical
prostatectomy specimen. The correlation between serum
prostate specific antigen and
residual cancer volume for all 67 patients was 0.66, and for stages A1 and A2 disease it was 0.64 and 0.70, respectively. All stage A1
cancer patients with a serum
prostate specific antigen value of 1 ng./ml. or less had
residual tumor volumes of less than 0.5 cc and all stage A
cancer patients with a serum
prostate specific antigen value of more than 10 ng./ml. had
residual tumor volumes of greater than 0.5 cc. Of the patients 51% had levels of 1 to 10 ng./ml. and serum
prostate specific antigen was not useful to predict
residual tumor volume in this group. Serum
prostate specific antigen measurements may be helpful in stage A1
cancer patients with levels of 1 ng./ml. or less, or greater than 10 ng./ml. in choosing the most appropriate
therapy.