Better detection of clinically significant prostate cancer with MRI plus targeted biopsy

By Marilynn Larkin

NEW YORK (Reuters Health) - 15/8/2019

Prebiopsy multiparametric magnetic resonance imaging (mpMRI) combined with targeted biopsy is associated with improved detection of clinically significant prostate cancer compared with transrectal ultrasonography-guided systemic biopsy alone, a systematic review and meta-analysis reveals.

"Prostate cancer...is usually diagnosed by taking 10 to 14 systematic samples from the prostate guided by ultrasound," Dr. Martha Elwenspoek of University Hospitals Bristol National Health Service Foundation Trust, UK, told Reuters Health by email. "However, these biopsies are unpleasant for patients, and can miss cancer even when it's present, misclassify the severity of the cancer, and cause side effects such as bleeding and infection."

"If biopsies could be targeted better, men wouldn't have to undergo so many and there would be less risk of getting a misleading result," she said.

"We reviewed all randomized controlled trials that compare the standard procedure with using pre-biopsy mpMRI for men with suspected prostate cancer who did not have a prostate biopsy before," she said. "(We) found that the use of pre-biopsy mpMRI combined with targeted prostate biopsy was better in detecting clinically significant cancers (i.e., cancers that require treatment) while fewer biopsy cores were taken per procedure."

"Our results also suggest that including mpMRI in the diagnostic pathway for prostate cancer may avoid unnecessary biopsies for some men and may lead to reduced side effects," she added.

Dr. Elwenspoek and colleagues' literature search yielded seven high-quality trials including 2,582 patients.

As reported online August 7 in JAMA Network Open, compared with systematic transrectal ultrasonography-guided biopsy alone, MRI with or without targeted biopsy was associated with a 57% improvement in the detection of clinically significant prostate cancer, a 33% potential reduction in the number of biopsy procedures, and a 77% reduction in the number of cores taken per procedure.

Further, one trial showed reduced pain and bleeding adverse effects, and systematic sampling of the prostate in addition to the acquisition of targeted cores did not significantly improve detection compared with systematic biopsy alone.

Dr. Elwenspoek said, "These findings suggest that using mpMRI to inform prostate biopsies is superior to the standard pathway and they support the use of mpMRI and a targeted biopsy to diagnose prostate cancer."

"However," she noted, "before mpMRI can be implemented in standard practice, the availability of mpMRI scanners needs to be improved and radiologists and urologists need appropriate training to interpret mpMRI images and to perform mpMRI-guided biopsies."

"Because only one study...reported biopsy complications, more evidence is needed to show whether reducing the number of cores per biopsy procedure will reduce the risk of side effects," she said. "Future research should perform longer follow-ups to confirm if side effects are indeed reduced in the MRI biopsy pathway."

"There are still concerns that clinically significant cancers may be missed in patients with negative mpMRI results," she noted. "Future research should investigate whether combining the scans with other measures, such as PSA density, can mitigate these risks."

Dr. Peter Albertsen of the University of Connecticut Health Center in Farmington, author of a related editorial, commented by email, "Historically, an elevated blood test has led to a prostate biopsy. Unfortunately, a majority of the cancers identified on these biopsies are low grade and often do not progress for 15-20 years or longer. Therefore, many men are given a diagnosis of prostate cancer that may never be clinically relevant."

"Over the past decade, prostate imaging using MRI has improved dramatically," he told Reuters Health. "We have learned that MRI imaging often will identify high grade prostate cancer, the cancers that are likely to progress, but will not flag the low-grade cancers."

"The UK has changed guidelines so that a man with an elevated PSA is referred for an MRI prior to biopsy," he said. "A biopsy is performed only if a lesion is identified on MRI."

"This rarely happens in the US," he noted. "One of the significant barriers is the cost of an MRI in the US, which is often 10 times more expensive than the UK."

"Many insurance companies will deny covering MRI prior to a prostate biopsy," he said. "They will claim that this practice is 'experimental' and not established standard of care."

"Another difference between the two countries is how health care is reimbursed. In the UK, performing prostate biopsies is a cost to the health care system and therefore something to be controlled," he explained. "In the US, prostate biopsies are a profit center for urologists and some healthcare systems and therefore less likely to be discouraged in favor of an imaging study."

SOURCE: http://bit.ly/2Z5EhNS and http://bit.ly/2Z002P2

JAMA Netw Open 2019.

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