[Significance of PSA-density: analysis in PSA gray zone cases]

We studied the sensitivity and specificity of digital examination and prostate specific antigen (PSA) density to detect prostatic cancer in those patients whose PSA values are in a range of 4 to 10 ng/ml or in a gray zone. Sextant prostate biopsy revealed 14 cases (17.2%) of prostatic cancer out of 81 PSA gray zone cases. The sensitivity of digital examination was 38.5%, and the specificity was 73.0%. If we use 0.29 as a PSA density cut-off value, the sensitivity was 70.0%, and the specificity was 70.0%. At a PSA density cut off value of 0.22, we could obtain 90% sensitivity, which was considered applicable for detection of cancer in PSA gray zone cases.