The Role of MRI in Prostate Cancer Management
Ashutosh K. Tewari, MBBS, MCh, is the Chairman of Urology at the Icahn School of Medicine at Mount Sinai Hospital in New York. He is scheduled speak about the emergence of magnetic resonance imaging (MRI) screening for prostate cancer at the 2nd International Prostate Cancer Symposium and Inaugural World Congress of Urologic Oncology, for which he is the course director. The conference is being held at the Icahn School of Medicine from September 6-9.
What clinical/laboratory findings identify men for whom MRI scans are appropriate?
Dr Tewari: Patients should be in the appropriate age group, age 50 or older, or age 45 if they are at higher risk for prostate cancer by having a family history of prostate cancer or breast cancer or if they are African American. Then we look at the PSA value and digital rectal exam (DRE) findings. If any of these is abnormal, that is when we starting thinking about MRI.
At present, what are the sensitivities and specificities of MRI for the localization of clinically significant prostate lesions?
Dr Tewari: This varies by institution, a meta-analysis showed that MRI sensitivity and specificity were 58% to 96% and 23% to 96%, respectively. In the PROMIS trial (Lancet 2017;389:815-822), the sensitivity and specificity for diagnosing any cancer higher than Gleason 6 was 88% and 45%, respectively.
Are there any clinical scenarios in which MRI scans should be the standard of care today?
Dr Tewari: In a patient who had a negative biopsy and PSA continues to be high, or DRE continues to be abnormal, we are concerned about the patient having cancer. Instead of jumping straight to biopsy, we should definitely consider an MRI before we perform a biopsy.
What would have to be demonstrated for MRI to be accepted for routine use in managing prostate cancer patients?
Dr Tewari: If MRI can reduce the number of biopsies without missing clinically significant cancers, it will become a viable option. We do about 1 million biopsies a year [in the United States], and that number needs to come down. We don't need to diagnose many cancers and we don't need to have so many negative biopsies. If MRI reduces the number of biopsies, it also decreases the complications, such as infections and sepsis, associated with the biopsies. MRI could be cost effective in the long run, but we don't have the data to show that right now. The PROMIS trial did a great job in demonstrating that MRI can be a useful intermediary before embarking on a biopsy.
What has been the response of third-party payers regarding reimbursement for MRI scans for prostate cancer patients?
Dr Tewari: It is easy to get an approval for a patient who had a negative biopsy in the past and continues to have an abnormal PSA or digital rectal exam finding. Other times it is not.