Combined MRI and PSA Strategy Improves Biopsy Decisions Compared with PSA Only: Longitudinal Observations of a Cohort of Patients with a PSA Level Less Than 20 ng/mL

Abstract

To assess the diagnostic performances of prostate specific antigen (PSA) and PSA with prostate magnetic resonance imaging (MRI) to predict prostate cancer in patients with PSA ≤ 20 ng/mL. Patients suspected of prostate cancer with a PSA test and prebiopsy MRI were included (n=881). Prostate biopsy results or follow-up clinical data for 2 years were used to determine the presence of prostate cancer. The diagnostic performance of PSA, MRI, and PSA with MRI (referred to as the protocol) was evaluated. The positive predictive value (PPV) and negative predictive value (NPV) of the MRI were calculated in subgroups of patients with specific ranges of PSA level. Prostate cancer and CSC were diagnosed in 220 and 162 patients, respectively. Adding MRI to PSA could greatly improve specificity and PPV (0.833 and 0.567) for detecting CSC, compared to PSA ≥ 4 ng/mL alone (0.248 and 0.0219). Even though the sensitivity of the protocol (0.679) was lower than PSA (0.938), the NPV of the protocol was comparable to PSA (0.929 vs. 0.924). The protocol consistently showed the superior PPV and NVP to PSA only in not only patients within the gray zone of PSA, but also in patients with higher PSA. In conclusion, this longitudinal observational study confirmed that adding prebiopsy MRI to PSA was consistently beneficial in patients with PSA ≤ 20 ng/mL for avoiding unnecessary biopsy despite decrease in the sensitivity.