Prostate tumour markers as an aid in the staging of prostatic cancer.

Serum acid phosphatase activity (ACP), prostate specific phosphatase (PAP) and prostate specific antigen (PSA) were measured in 100 patients with prostatic cancer. The patients were divided into 4 groups: T1-2 MO, T3-4 MO and M1 patients with less than or equal to 10 or greater than 10 metastatic foci in bone scintigraphy. The mean serum ACP levels were almost identical in the T1-2 MO and T3-4 MO groups and there was no significant difference between the mean PAP values. Significantly higher PSA levels were observed in the MO patients in the extracapsular category compared with those in the intracapsular category. The mean serum levels of all 3 tumour markers were significantly higher in the M1 than in the MO category. PSA seems to be the marker of choice as a diagnostic aid for differentiating between patients with intracapsular and those with extracapsular tumour growth. In prostatic cancer patients with bone metastases these markers were of similar value for staging the disease.