MRI before biopsy better than TRUS in prostate cancer diagnosis
MRI, with or without targeted biopsy, detects more clinically significant prostate cancer and less clinically insignificant prostate cancer than the standard transrectal ultrasonography (TRUS)-guided approach, enabling more than one-quarter of patients to safely avoid a biopsy altogether.
“These practice-changing findings from the PRECISION [Prostate Evaluation for Clinically Important Disease: Sampling Using Image Guidance or Not?] trial suggest that we need to fast-forward MRI to the diagnostic pathway prior to prostate biopsy,” commented Dr Declan Murphy of the Peter MacCallum Cancer Centre in Melbourne, Australia, who discussed the PRECISION findings at the European Association of Urology (EAU) 2018 Congress.
The multicentre, randomized, noninferiority PRECISION trial was conducted in 500 men with a clinical suspicion of prostate cancer (ie, abnormal prostate-specific antigen [PSA] level or digital rectal examination, or both) who had not undergone biopsy previously. [N Engl J Med 2018, doi: 10.1056/NEJMoa1801993]
In the MRI group, targeted biopsy (without standard biopsy cores) was performed in men with MRI results suggestive of prostate cancer based on the Prostate Imaging-Reporting and Data System version 2 (PI-RADS v2), while those with MRI results not suggestive of prostate cancer were not offered biopsy. In the TRUS group, biopsy was performed using a standard transrectal technique to obtain 10–12 biopsy cores.
The primary endpoint was the proportion of men with clinically significant prostate cancer, defined as a Gleason score of 3+4 or above.
“In the MRI group, 28 percent of men had a result on multiparametric MRI that was not suggestive of prostate cancer [ie, PI-RADS v2 score of ≤2], and they did not undergo biopsy,” reported investigator Dr Veeru Kasivisvanathan of the University College London, UK.
“Clinically significant prostate cancer was detected in 38 percent of men in the MRI-targeted biopsy group compared with 26 percent of men in the standard biopsy group [p=0.005],” he continued. “The results show that MRI, with or without targeted biopsy, is superior to the standard TRUS-guided approach.”
Among study participants who underwent biopsy, a median of 4 biopsy cores were obtained in the MRI-targeted biopsy group, compared with a median of 12 cores in the standard biopsy group.
In addition, significantly fewer participants in the MRI-targeted biopsy group received a diagnosis of clinically insignificant prostate cancer compared with the standard biopsy group (9 percent vs 22 percent; p<0.001).
The percentage of biopsy cores positive for cancer was also higher in the MRI-targeted biopsy group compared with the standard biopsy group (44 percent vs 18 percent).
At 30 days, participants in the MRI-targeted biopsy group reported fewer complications than those in the standard biopsy group, with fewer participants having blood in urine (30 percent vs 63 percent), blood in semen (32 percent vs 60 percent), pain at the site of the procedure (13 percent vs 23 percent), rectal bleeding (14 percent vs 22 percent), or erectile dysfunction (11 percent vs 16 percent).
According to the investigators, the lower rates of complications reflected the lower percentage of men undergoing biopsy and fewer biopsy cores obtained in the MRI-targeted biopsy group.