Comparison of prostate-specific antigen corrected for total prostate volume and transition zone volume in a population-based screening study

Abstract

Objectives: To compare the discriminatory potential between prostate cancer and benign conditions of the prostate in a population-based screening study, of serum prostate-specific antigen levels (PSA) and PSA corrected for both the total prostate volume (PSA-D) and the transition zone volume (PSA-T).

Methods: In a randomized population-based screening study (Rotterdam section of the European Randomized Study of Screening for Prostate Cancer), in which 10,865 men have been screened, the biopsy results of 1202 men with PSA levels of 4 ng/mL or more were evaluated. Planimetric and prolate ellipsoid volumes of the total prostate as well as of the transition zone were measured. The measured volumes were compared with the volumes of 57 radical prostatectomy specimens through Spearman's rank correlation coefficient and agreement tests. A receiver operating characteristic (ROC) curve analysis was done of sensitivity and specificity of biopsy indications through PSA and PSA corrected for the volumes measured with transrectal ultrasound.

Results: In the 1202 men studied, 361 cases of prostate cancer were diagnosed. Both PSA-D and PSA-T showed a significantly higher area under the ROC curve (0.77 and 0.79, respectively) than PSA alone (area 0.65). There was no significant difference between PSA-D and PSA-T. The use of a PSA-D threshold value of 0. 10 ng/mL/cc would have avoided 28% of biopsies at the cost of 10% of detectable cancers. A PSA-D threshold of 0.15 ng/mL/cc would have avoided 73.8% of biopsies at the cost of not diagnosing 43.8% of detectable cancers.

Conclusions: The planimetrically obtained prostate volume showed a more favorable agreement with the radical prostatectomy volume than the prolate ellipsoid volume. The discriminatory potential of the corrected PSA value is better at predicting the results of needle biopsy of the prostate when compared with PSA alone. The use of the transition zone volume for this correction results in a higher discriminatory potential when compared to the use of the total prostate volume; however, the observed difference was not statistically significant.