Diagnostic performance of prospectively assigned Likert scale scores to determine extraprostatic extension and seminal vesicle invasion with multiparametric MRI of the prostate

OBJECTIVE. The objective of this study was to determine the diagnostic performance of a prospectively assigned 5-point Likert scale for determination of extraprostatic extension (EPE) and seminal vesicle invasion (SVI). MATERIALS AND METHODS. This study was a single-center, retrospective analysis of prospectively collected data including all men with abnormal 3-T multiparametric MRI and subsequent radical prostatectomy between November 1, 2016, and September 30, 2017. Scores from a 5-point subjective Likert scale (1 = highly unlikely, 5 = highly likely) for the likelihood of EPE and SVI were prospectively assigned during clinical MRI interpretation. EPE and SVI status at whole-mount prostatectomy specimen served as the standard of reference. RESULTS. Among the 89 eligible men, whole-mount histopathology revealed organ-confined prostate cancer, EPE, and SVI in 49% (44/89), 46% (41/89), and 18% (16/89) of patients, respectively. Of the pathologically proven cases of EPE, 18% (2/11), 17% (4/24), 65% (17/26), 46% (6/13) and 80% (12/15) were assigned Likert scores of 1–5, respectively. Of the pathologically proven cases of SVI, 5% (3/58), 11% (2/18), 66% (2/3), 66% (2/3) and 100% (7/7) were assigned Likert scores of 1–5, respectively. The positive predictive values for scores of 4 or 5 were 64% for EPE and 90% for SVI. The negative predictive values for scores of 1 or 2 were 87% for EPE and 93% for SVI. Likert scores for EPE (odds ratio, 2.1; 95% CI, 1.3–3.4) and for SVI (odds ratio, 4.7; 95% CI, 2.3–9.6) were both associated with EPE and SVI on multivariate analysis. CONCLUSION. A 5-point Likert scale can effectively convey the degree of suspicion of EPE and SVI on multiparametric MRI of the prostate, facilitating informed decision-making.