Relationship of Serum Acid Phosphatase Determination to Presence of Bone Metastases from Carcinoma of Prostate

Abstract

The serum acid phosphatase detn. is a valuable adjunct in the diagnosis of metastatic bone lesions from carcinoma of the prostate. Acid phosphatase values up to 4.0 King-Armstrong U. should be considered as normal. In the interpretation of figures between 4.0 and 6.0 units utmost caution should be used, especially in those cases in which the alkaline phosphatase activity is either under the avg. normal (below 6.0 units), or elevated above 12.0. In these borderline cases, detns. should be made repeatedly, and conclusions drawn by comparing the obtained figures with those previously determined in conjunction with the clinical picture. A marked elevation of acid phosphatase in the blood serum is indicative of metastatic bone involvement from carcinoma of the prostate. Detn. of the serum acid phosphatase should become a routine measure in all cases of clinically proven or suspected prostate carcinoma. If marked elevation of the acid phosphatase activity with negative pelvic girdle films is present, x-ray pictures of the entire skeletal system should be made, to attempt to discover a bone lesion elsewhere than in the bony parts, most frequently affected by metastatic carcinoma from the prostate. Normal values for acid phosphatase are not an absolute proof of the absence of bone metastases, but bone lesions appear to be less likely. Determining the acid and alkaline phosphatase activity gives an indication as to the interpretation of questionable bone areas in an x-ray picture of a patient suffering from carcinoma of the prostate. The same applies for all metastatic bone tumors, as long as the primary focus has not been established beyond doubt. Acid and alkaline phosphatase detns. should be repeated every 3 months, regardless of whether or not the result obtained at the first examination yielded normal values. As already suggested by Gutman, Gutman and Robinson, it is understandable that a rapidly progressive elevation of the acid phosphatase activity should be regarded as an unfavorable prognostic sign.