Creatine kinase isoenzyme (CK-BB) by RIA as a follow-up marker in stage D cancer of the prostate: comparison with PAP RIA.

Fifty-nine patients with stage D carcinoma of the prostate under different modalities of treatment were studied for creatine phosphokinase isoenzyme BB (CK-BB) and prostatic acid phosphatase (PAP) levels in serum by radioimmunoassay (RIA) technique, in order to study the possible use of CK-BB as a follow-up marker compared to PAP. Thirty-three patients were in stable, 19 in progressive, and seven in regressive clinical state. CK-BB was above normal level in 52 (88%) out of 59 patients with no statistically significant difference between the three clinical states. On the other hand, PAP was above normal level in only 23 patients (38.98%) with statistically significant difference between the three clinical states (P less than 0.001). The PAP/CK-BB index was below 1 in stable and regressive condition, while it was above 1 in eight out of 19 patients with progressive disease. The PAP/CK-BB index may be of prognostic importance. CK-BB by RIA was abnormal in more cases than PAP. In this way CK-BB reflects the presence of the tumor and may be used for diagnosis; however, it does not reflect the clinical response as PAP does.