[The role of the absolute value and "density" of the prostate-specific antigen estimated echographically in the selection of patients to undergo a biopsy in suspected prostatic carcinoma. A comparison between PSA, palpation and echography in 95 patients undergoing echo-guided endorectal prostatic biopsy].
We retrospectively reviewed the findings relative to 95 patients with known prostate specific antigen (PSA) values who had undergone digital rectal examination, transrectal US and US-guided biopsy for suspected prostate carcinoma. Histology (48 adenocarcinomas, 26 BPHs, 12 inflammations and 9 negatives) was compared with results from rectal examination, prostate US, PSA values and "density" (PSA/prostatic volume, as measured with US). PSA values < 4 ng/ml exhibited 90% negative predictive value and PSA > 10 ng/ml 70.8% positive predictive value. In the intermediate range (4-9.9 ng/ml) the positive predictive value of PSA was 44.4% and its negative predictive value was 55.5%. PSA density did not affect predictive values in the two groups with PSA < 4 and > 10 ng/ml, while in the intermediate 4-9.9 ng/ml group, positive predictive value raised to 62.5% and negative predictive value to 81.8%, thus increasing the specificity of PSA values and US findings. Our results suggest that PSA should be the examination of choice in the patients with prostatic disease. Follow-up with PSA dosage after one year may be suggested when PSA < 4 ng/ml. PSA density can be helpful in patients with PSA values ranging 4-9.9 ng/ml; biopsy should be performed when the index > 0.15, while follow-up at 6 months should be performed when the index < 0.15. PSA values > 10 ng/ml require further evaluation with rectal examinations, prostate US and US-guided biopsy. Random biopsies are suggested when PSA values are > 20 ng/ml.