In an effort to reduce over treatment, “active surveillance” has become a realistic option for men with prostate cancer whose tumors do not need urgent attention and may never advance into a life threatening illness.
MRIs have always been a common tool in screening for prostate cancer reoccurrence. Now, researchers from Memorial Sloan-Kettering Cancer Center in New York recently reported that endorectal magnetic resonance imaging (MRI) can be added to the clinical evaluation for men with clinically low prostate cancer risk in order to measure their qualifications for active surveillance. Criteria for patients eligible for active surveillance has been constantly debated.
Lead investigator Hebert Alberto Vargas, MD, Department of Radiology, Memorial Sloan-Kettering Cancer Center says:
“Among patients initially diagnosed with clinically low risk prostate cancer, those with tumors not clearly visualized on MRI were significantly more likely to demonstrate low risk features when a confirmatory biopsy was performed, while patients with tumors clearly visualized on MRI were significantly more likely to have their disease status upgraded on confirmatory biopsy.”
The experts, whose findings were published in the Journal of Urology, assessed 388 patients who had a preliminary prostate biopsy between 1999 and 2010, a Gleason score (measures prostate cancer aggressiveness) of 6 or less, and had a biopsy to verify evaluation within 6 months of diagnosis. An endorectal MRI was given to patients between the preliminary and verification biopsies.
Three different radiologists with different ranges of experience examined the MRI studies. The first radiologist was fellowship trained and had only read about 50 prostate MRI examinations before the study (reader 1). The second had vast experience in prostate imaging and had read approximately 500 prostate MRI examinations (reader 2). The last, also fellowship trained, had experience interpreting over 5,000 prostate MRI examinations. Each of them assigned a score of 1 to 5 for the existence of tumor on MRI, 1 being absolutely no tumor and 5 being definitely a tumor.
On confirmatory biopsy, Gleason scores were raised in 20 percent of the cases. Patients with higher MRI scores had an increased likelihood of an upgraded disease upon confirmatory biopsy. An MRI score of 2 or less was linked to low risk qualities. Agreement on MRI scores were considerable between readers 2 and 3, but only average between readers 1 and readers 2 and 3. The findings demonstrate MRI examinations read by experienced radiologists with appropriate training, can help decide eligibility for active surveillance.
Active surveillance lets patients with low grade tumors avoid over treatment and unnecessary negative side effects such as erectile disfunction and bladder problems. Accurate identification of patients with low risk disease and unlikelihood of having disease progression is crucial to the success of active surveillance.
“The fact that clear tumor visualization on MRI was predictive of upgrading on confirmatory prostate biopsy suggests that prostate MRI may contribute to the complex process of assessing patient eligibility for active surveillance,” Dr. Vargas concludes.
MRIs could have the ability to help limit the risk of biopsy under grading, reduce over treatment, and eliminate uncertain diagnosis.
Written by Kelly Fitzgerald