Prostate Specific Antigen Density (PSAD) in the Detection of the Prostate Cancer

Choi, Eun Ho; Kim, Choung Soo; Ahn, Tai Young

Abstract

Prostate specific antigen(PSA) is an extremely valuable tumor marker. However, its use in detection of prostate cancer is limited by low sensitivity and specificity. To enhance the accuracy of serum PSA we used the quotient of serum PSA and prostate volume, which is referred to as prostate specific antigen density(PSAD). Prostate volume in this study was calculated from transrectal ultrasonographic determinations using the formula, length x width x depth x 0.52 = volume. The serum PSA was analyzed using the Hybritech assay. Prostate biopsy was performed transperineally from at least six sites. The cancer detection rate was 3.3%(three out of 91 patients) in the group with PSA value of less than 4.0ng/ml and 11.3%(eight out of 71 patients) in the group with PSA value of 4.1 to 10. 0ng/ml. In the latter group, mean PSA value for the positive(n=8) and negative(n=63) biopsy group was 7.10+/-1.22 and 6.61+/-1.79ng/ml each(p=0.4630), but mean PSAD value was 0.275+/-0.089 and 0.187+/-0.078 each(p=0.0045). In the group of 38 patients with PSA value of 10.1 to 20.0ng/m1, the cancer detection rate was 15.8%(six patients) and the mean PSA value for the positive(n=6) and negative(n=32) biopsy group was 15.5+/-3.09 and 13.4+/-2.78ng/ml each(p=0. 1038), but the mean PSAD value was 0.535+/-0.082 and 0.334+/-0.182 each(p=0.0128). These results suggest that PSAD be useful in distinguishing BPH and prostate cancer in the patients with intermediate PSA values(4.1ng/ml to 20.0ng/ml).