Fast MRI protocol accurately identifies prostate cancer at lower cost

By Reuters Staff

NEW YORK (Reuters Health) - 19/7/2019

A fast MRI protocol can accurately identify prostate cancer in biopsy-naive men at lower cost with minimally increased biopsy rates, researchers from the Netherlands report.

Fast MRI has been suggested as a means of reducing examination time and cost while retaining sufficient diagnostic accuracy to rule out high-grade prostate cancer in biopsy-naive men.

Dr. Marloes van der Leest from Radboud University Medical Center, in Nijmegen, and colleagues investigated the diagnostic performance of currently used multiparametric (mp)MRI versus noncontrast, biparametric MRI in three planes (bp-MRI) or one plane ("fast" bp-MRI) to detect high-grade prostate cancer in a prospective study of 626 men.

The patients were 50 to 75 years old (median, 65 years) and had a prostate-specific antigen (PSA) value of at least 3 ng/mL (median, 6.4 ng/mL) and no history of prior biopsy.

Both mp-MRI and bp-MRI were scored as nonsuspicious in 309 men (49%), whereas lesions were nonsuspicious in 47% of men by fast bp-MRI. Lesions were scored as equivocal in 6.4% by mp-MRI, 7.8% by bp-MRI and 11% by fast bp-MRI.

With combined histopathology as the reference standard, the sensitivity for high-grade prostate cancer was 95% for all three protocols. Specificity was lower for the fast bp-MRI protocol (65%) than for the other protocols (69%), the team reports in European Urology, online June 2.

The negative predictive value for high-grade prostate cancer was 97% for all three protocols, whereas the positive predictive value was lower for the fast bp-MRI protocol (54%) than for the other protocols (57%).

As a result, fast bp-MRI would result in additional biopsies in 14 (2.2%) men, only three of whom would show high-grade lesions.

Compared with the standard mp-MRI protocol, direct costs would be an estimated 143.35 Euros ($162.26), or 54%, lower with fast bp-MRI and 98.95 Euros ($112), or 37%, lower with bp-MRI.

"Fast bp-MRI can double prostate MRI capacity at lower expenses," the researchers conclude. "This is, however, at the cost of ~2% more biopsies and ~1% more overdetection of low-grade prostate cancer. In order to implement this technique in nonexpert, low-volume, lower-field-strength scanners, further prospective studies have to be performed." Dr. van der Leest did not respond to a request for comments.

SOURCE: https://bit.ly/2YkmYFf

Eur Urol 2019.

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