[Circulating prostatic-specific antigen in benign hypertrophy and localized prostate cancer: can PSA be considered a...

Prostate-specific antigen (PSA) is increasingly used in the diagnosis of prostatic pathology. Its usefulness in the early diagnosis of prostatic cancer is controversial. The aim of the study is to evaluate the sensitivity and specificity of PSA in a population with prostate diseases. Moreover, we wanted to know if the measure of the prostate volume may increase the sensitivity of the test. In benign prostatic hypertrophy (88 patients), a good correlation exists between circulating PSA and the prostatic volume or the volume of the adenoma. This correlation disappears in the presence of an adenocarcinoma at the profit of the tumor volume (46 patients). Used as a means of screening for cancer, the serum level of PSA with a threshold value of 2.5 ng/ml has a sensitivity of 91% and a specificity of 32%. The sensitivity is 50% and the specificity is 85% at a level of 15 ng/ml. Taken alone, the level of PSA is inadequate for diagnosis: If the lower level is chosen (2.5 ng/ml), the majority of benign prostatic hypertrophies will be the object of a biopsy. If the higher level is chosen (15-23 ng/ml), 50% of localized cancers of the prostate will escape detection. Nevertheless, a level of PSA < 15 ng/ml is an argument for a strong suspicion in favor of an adenocarcinoma of the prostate. The capacity of BPH to "secrete" serum PSA is five times greater than that of the normal peripheral prostate, and the capacity of cancer is 20 times greater than that of an adenoma. The individual variability of serum PSA per cubic centimeter of prostatic tissue is too great to allow a precise interpretation as a function of volume.