Magnetic resonance imaging (MRI)/fusion targeted prostate biopsy may improve detection of clinically significant tumors in prostate cancer patients on active surveillance (AS) undergoing confirmatory biopsy, researchers reported at the Society of Urologic Oncology 17th annual meeting in San Antonio, Texas.
“We observed that 70% of AS patients have MRI-detectable lesions, the majority of which are consistent with low-grade disease,” senior author J. Kellogg Parsons, MD, MHS, of the University of California San Diego in La Jolla, told Renal & Urology News. “MRI/fusion targeted biopsy in patients with PI-RADS 4 and 5 lesions was superior to systematic biopsy for the detection of clinically significant disease, suggesting that MRI and selective, targeted biopsy of PI-RADS 4 and 5 lesions should be considered in AS patients.”
In a study of 356 AS patients, a team led by Dr Parsons and first author Zachary Hamilton, MD, who presented study findings, compared MRI/fusion targeted biopsy (TB) to standard ultrasound-guided systematic biopsy (SB) for detecting Gleason 3 + 4 = 7 or higher disease. A total of 195 patients (58%) underwent prostate MRI after the initial diagnostic biopsy. Of these, 138 (71%) had prostate lesions detectable on MRI.
After implementation of TB in May 2014, 42 AS patients underwent confirmatory MRI/fusion TB: 9 (21.4%), 19 (45.2%), 7 (16.7%), and 7 (16.7%) with PI-RADS 2, 3, 4, and 5 lesions, respectively. MRI-guided biopsy of the 14 patients with PI-RAD 4-5 lesions resulted in upgrading for 12 (85.7%). By comparison, of 106 patients who underwent confirmatory SB, 30 (28.3%) had their cancer upgraded.
The study revealed a significantly higher rate of disease upgrading associated with PIRADS 4-5 lesions when compared with PI-RADS 1-3 lesions (85.7% vs 14.3%) and TRUS-guided SB (85.7% vs 28.3%). Additionally, PI-RADS 4-5 lesions were significantly and independently associated with 16-fold increased odds of upgrading on repeat biopsy. Upgrading of disease was significantly associated with nearly 5.8-fold increased odds of progression to definitive local therapy.
Hamilton Z, Nseyo U, Cotta B, et al. Clinical utility of MRI/fusion biopsy in prostate cancer patients on active surveillance. Poster presented at the Society of Urologic Oncology 17th annual meeting, San Antonio, November 30-December 2. Poster 95.