MRI adds real value to prostate cancer diagnostics

Diagnostic prostate MRI can be a good tool for triaging biopsy candidates, as the one-two punch of that exam followed by MRI-guided biopsy of suspicions lesions has again proven not only clinically efficacious but also cost-effective when compared with transrectal ultrasound-guided biopsy.

The researchers behind the new findings further discovered that in-gantry MRI-guided biopsy benefits the patient by boosting quality-adjusted life-years (QALYs) while remaining below the willingness-to-pay threshold of $50,000 per QALY.

Their study was published online May 17 in Radiology.

Shivani Pahwa, MD, and colleagues at Case Western Reserve University began with a decision-analysis model created for men who had never been biopsied but were referred for such after abnormal digital exam or elevated PSA levels.

The team ended up evaluating a total of seven variations of imaging-based prostate cancer diagnosis of men in three age groupings (41 to 50, 51 to 60 and 61 to 70).  

They found the overall most cost-effective method was noncontrast diagnostic MRI followed by either cognitively guided biopsy when suspicious lesions were present on diagnostic MRI or, in the case of negative MRI, the foregoing of a standard biopsy.

Meanwhile, noncontrast MRI followed by in-gantry MRI-guided biopsy—again, with no standard biopsy if MRI findings were negative—led to the highest net health benefit gain as compared with the standard biopsy strategy.

The authors additionally report that MRI-guided strategies remained cost-effective when sensitivity analysis was performed with Gleason-scored cutoff points to separate clinically significant from insignificant cancers, yielding an additional net health benefit ranging from 0.008 to 0.25 QALY compared with the standard biopsy strategy.

“Even small increments of improvement in sensitivity or specificity of diagnostic MR imaging for detecting clinically significant prostate cancer by adding gadolinium contrast material are cost-effective,” they write.

Pahwa et al. note that their results are consistent with previous cost-effectiveness studies assessing MRI-guided methods for detecting prostate cancer.

Among the limitations they acknowledge are their use of Medicare-based data, which may not apply to patients covered by other payers, and their use of studies from a single institution. The latter owed to the unavailability of randomized clinical trials comparing MRI-guided pathways with the standard biopsy pathway, they note.

“One likely reason for the observed cost-effectiveness of MR imaging-guided strategies is the propensity of MR imaging to not ‘see’ low-risk tumors,” the authors write in their discussion. “The size of the tumor correlates with aggressiveness, and therefore, by avoiding the detection of microscopic clinically insignificant cancers, MR imaging helps avoid unnecessary biopsies, associated complications and other downstream events that may occur after a diagnosis of cancer.”