The Laboratory Diagnosis of Prostatic Adenocarcinoma

At the close of each decade, we are reminded by medical statisticians that our longevity increases significantly. For the male, especially if he be of black race this statement has an ironic twist. Over age 70, prostatic "cancer" assumes the leadership list of "cancers" in general, supplanting lung and colo-rectal. One interesting point evolved by careful autopsy studies suggests that this incidence is found coincidentally and is not primarily responsible for the cause of death. This illustrates a different significance to other neoplasia, and offers useful opportunities to study the evolution of a neoplasm. In contrast to other "cancers" (for example pulmonary), the histological nature of the tumor is almost totally derived from the acinar lobules and designated adenocarcinoma. Neoplasia arising from the fibromuscular stroma (sarcoma) and metaplastic ductus (squamous cell carcinoma) constitute less than 1% of all prostate cancers. Histological appearances, however, are not as simple as hoped. As in many tumors the section may present a uniform well-differentiated adenocarcinoma in which the acinar structure is well maintained--yet at the opposing end of the spectrum show a fatally dedifferentiated picture whose organ origin is difficult to determine. Adding to the complication is the wide variation, far more commonly seen, of the mixed tumor with all variations presenting a composite panorama of histology. Indeed the pure type is rare. As with all neoplastic disease, early detection is critical, since opportunity for cure with the various forms of therapy from surgery through radiation to chemotherapy are increasing rapidly. The prostate gland is relatively accessible to the trained finger of the physician and later stages of the disease are palpable. However, the earliest Stage (I) is not discovered by rectal examination, hence provides an ideal opportunity for the serum tumor marker, to identify disease. Since 1938, disseminated prostatic adenocarcinoma has been associated with elevation of activity of an enzyme acid phosphatase. Although there are several isoenzymes the prostatic specific one has in the past been assayed by different spectrophotometric techniques using selective substrate and chemical inhibition. More recently various immunological methods have added a greater sensitivity and specificity to the early detection of prostatic adenocarcinoma. However is should be clearly stated that prostatic acid phosphatase is not cancer specific and can