AUA 2018: Use of MRI for Prostate Cancer Screening and Management
Use of magnetic resonance imaging (MRI) in the diagnosis of prostate cancer is increasing and brings added value to screening and surveillance, according to new studies presented this year during the 113th Annual Meeting of the American Urological Association (AUA). Four studies highlighting the effectiveness of MRI in the diagnosis and management of prostate cancer were presented during a special press conference.
Prostate Health Index and Multiparametric MRI to Predict Prostate Cancer Grade Reclassification in Active Surveillance
When used together, multiparametric MRI (mpMRI) and Prostate Health Index (PHI) may be useful for decreasing the burden of prostate biopsies in men on active surveillance, according to Johns Hopkins researchers (Abstract MP12-20). While both mpMRI and PHI have shown independently to be valuable in predicting prostate cancer grade reclassification (Gleason score > 6) in patients enrolled in active surveillance, researchers at Johns Hopkins aimed to identify the value of combining them for the purpose of predicting grade reclassification at the next active surveillance biopsy.
Researchers retrospectively identified 205 men enrolled in the institution's active surveillance program who underwent mpMRI and PHI within 6 months of each other followed by a systematic mpMRI transrectal ultrasound (TRUS) biopsy. They then evaluated PHI and PHI density across Prostate Imaging Reporting and Data System (PI-RADS) V2.0 scores and compared results between men with and without grade reclassification before calculating receiver operating characteristic curves to compare the diagnostic value of the PI-RADS score combined with PHI, PHID, or prostate-specific antigen doubling time (PSAD) for grade reclassification.
Results showed:
- Men with grade reclassification on biopsy had a higher median PHI (34.6 vs 31.6, P = .03) and PHID (0.79 vs 0.56, P = .03) compared to men without grade reclassification.
- PSA and PSAD were not significantly different between men with grade reclassification and those without it.
- Combined use of PHI < 24.4 and PI-RADS ≤ 3 could have avoided 24% of active surveillance biopsies at the cost of missing only 4% of grade reclassification.
Contemporary National Trends in Prostate MRI Among Patients Undergoing a Prostate Biopsy
A growing number of men are undergoing prostate biopsy with mpMRI as opposed to conventional TRUS biopsy. Using a large cohort (more than 1 million men aged 40–80 years diagnosed with an elevated PSA from 2010–2016) from a private insurer database, researchers examined the adoption of the mpMRI (Abstract MP77-14).
Results showed:
- Of the men diagnosed with elevated PSA, 3.9% underwent a prostate biopsy.
- Annual rates of MRI among those men receiving prostate biopsies increased significantly, from 5.2 per thousand in 2010 to 13.5 per thousand in 2016.
- Use of mpMRI increased across all age groups; however, the largest and only significant increase in use was in men aged 60 to 65 (4.4 in 2010 to 16.0 in 2016).
Negative MRI: Which Patients Could Safely Avoid Prostate Biopsy?
mpMRI is an effective tool to rule out clinically significant (Gleason ≥ 3+4) and high-grade (Gleason ≥ 4+3) prostate cancers, and results could identify patients most likely to benefit from biopsy, according to this multi-institutional study of 401 patients (Abstract MP57-08). Using data from prostate biopsy databases at two referral centers, researchers examined diagnostic accuracy of mpMRI in men with negative mpMRI (PI-RADS < 3 or Likert score < 3) prior to biopsy.
Results showed:
- Of the 401 patients with negative mpMRI, 136 were diagnosed with prostate cancer.
- 46 patients were diagnosed with clinically significant disease and 20 patients with high-grade disease.
- Negative predictive values for identifying prostate cancer, clinically significant prostate cancer, or high-grade prostate cancer were 66% (265/401), 89% (355/401), and 95% (381/401).
- PSA doubling time and history of previous negative biopsy were independent predictors of nonclinically significant disease.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
