Possibilities of using novel diagnostic indices to detect prostate cancer

Introduction and Objectives. The low specificity of PSA for the early diagnosis of prostate cancer was a reason for elaboration of new diagnostic methods. The aim of the study was to create novel diagnostic indices of random mathematic combinations of numeric clinical patient parameters and to estimate these values as a diagnostic tool for the detection of prostate cancer.

Material and Methods. A total of 326 male patients aged 47—83 years (mean age was 65.56.5 years) who had undergone TRUS-guided 12-core systematic transrectal prostate biopsy were included in the study. The detection rate of prostate cancer was 43,6%. To compare the accuracy of the diagnostic indices, receiver-operator characteristic (ROC) curves were plotted for any of the indices and the areas under ROC curves were calculated. Age, prostate volume, transition zone volume, peripheral and central zone volume, concentration of PSA, and biopsy result were recorded in the patients.

Results. A total of 37 indices were generated. The maximal accuracy equal to 0,664 was in «PSA Density in Transition Zone (PSAD-TZ) × Age». «PSAD × Age» and «PSAD-TZ» with an accuracy equal to 0,656 and 0,655 were on 2nd and 3rd rank positions, respectively. PSA with an accuracy of 0,583 was on 31st rank position only. With 90% specificity, the sensitivity of «PSAD × Age», «PSAD-TZ × Age», and «PSA» were 24, 22, and 19%, respectively. With 80% specificity, the sensitivity of «PSAD-TZ × Age», «PSAD × Age», and «PSA» were 47, 40, and 30%, respectively. With 90% sensitivity, there were no differences in the reduction in unnecessary biopsies. At the same time, with 80% sensitivity, «PSAD-TZ*Age» showed a 17% reduction in unnecessary biopsies as compared with «PSA» (р = 0,001).

Conclusions. The indices «PSAD-TZ × Age» and «PSAD × Age» may be used in counseling patients with suspected prostate cancer. Further multicenter studies may be required to evaluate the effectiveness of the novel indices widely used in clinical practice.