Limiting overdiagnosis of low-risk prostate cancer through an evaluation of the predictive value of transrectal and power Doppler ultrasonography.

Abstract

Overdiagnosis induced by prostate cancer screening makes necessary a better selection of candidate patients for prostate biopsy. The objective of our study is to assess the probability of having a high- or low-risk lesion that could require active surveillance (AS) after biopsies and a normal or abnormal examination, including transrectal and power Doppler ultrasonography (TRUS-PDS). Four hundred and twenty-nine consecutive patients with a PSA level <10ng/ml and a normal digital rectal examination (DRE) had guided biopsies in a prospective study. We used D'Amico's criteria to assess the risk of a biological recurrence and Dall'Era's criteria to assess possible AS. The TRUS-PDS was considered positive if one biopsy was positive in the same sextant as the suspect image. One hundred and seventy-seven out of 429 (41%) T1c cancers were diagnosed; 131 out of 177 (74%) could be qualified as low risk, and 119 out of 177 (67%) could require AS. The TRUS-PDS was normal in 285 of 429 patients (66%). With a normal TRUS-PDS, the probability of not having cancer with a high or intermediate risk was 96% (negative predictive value). With an abnormal TRUS-PDS, the probability of having a positive biopsy was 59%, and the probability of having a significant cancer was 30%, according to the Dall'Era criteria. When TRUS-PDS was normal, these probabilities significantly decreased to 32 and 5%, respectively (p<0.01). Patients with a PSA level <10ng/ml, a normal DRE, and a normal TRUS-PDS have a less than 5% risk of high- or intermediate-risk cancer.