Serum acid phosphatase in patients with localised prostatic cancer, benign prostatic hyperplasia or normal prostates.

Serum acid phosphatase levels were determined in 247 men with surgically confirmed intracapsular prostatic cancer (30 patients), benign prostatic hyperplasia (BPH) (114 patients) or palpably normal prostates (103 men). Both radioimmunoassay (245 cases) and an enzymatic method (218 cases) were used. Using radioimmunoassay, the mean serum prostatic acid phosphatase (PAP) level was significantly higher in patients with BPH than in patients with intracapsular cancer or men with normal prostates. The weight of hyperplastic tissue removed during operation in the BPH group correlated closely with PAP concentrations. Age or the presence (or absence) of an indwelling catheter had no effect on PAP concentration. Using the enzymatic method, the highest levels of acid phosphatase were also detected in patients with BPH but the difference was less marked. It was concluded that intracapsular cancer does not elevate serum acid phosphatase levels as determined by radioimmunoassay or an enzymatic method. BPH alone leads to significant rises in PAP concentrations. The degree of BPH correlates with PAP levels.