Prostate Cancer: Low Risk Doesn’t Always Mean Low Risk!

prostate illustration

Background: Prostate cancer is the most frequently diagnosed cancer in men aside from skin cancer. An estimated 233,000 new cases of prostate cancer will occur in the United States in 2014. Of those, nearly 30,000 men will die.

More and more men who believe they have low-risk prostate cancers are opting for active surveillance, forgoing treatment and monitoring the cancer closely with prostate-specific antigen (PSA) tests, digital rectal exams and ultrasounds at regular intervals to see if their tumors are growing. Nearly 400 men are now enrolled in the UCLA Active Surveillance program, the largest in Southern California.

What You Need to Know: According to a new UCLA study, selection of men for active surveillance should be based not on the widely used conventional biopsy, but with a new, image-guided targeted prostate biopsy. The new biopsy method, pioneered by a multi-disciplinary team on the Westwood campus, is now a routine part of the UCLA active surveillance program.

UCLA researchers found that conventional “blind” biopsy failed to reveal the true extent of presumed low-risk prostate cancers, and that when targeted biopsy was used, more than a third of these men had more aggressive cancers than they thought. Their aggressive cancers were not detected by conventional blind biopsy using ultrasound alone, and the men were referred to UCLA’s active surveillance program thinking they were at no immediate risk.

The targeted biopsy method is performed by combining magnetic resonance imaging (MRI) with real-time ultrasound, a method of fusion biopsy, in a device known as the Artemis. Previous work from UCLA demonstrated the value of the new procedure in finding cancers in men with rising PSA who had negative conventional biopsies. This study is the first to show the value of using it early in the selection process for men interested in active surveillance.

“These findings are important as active surveillance is a growing trend in this country,” said study senior author Dr. Leonard Marks, a professor of urology and director of the UCLA Active Surveillance Program. “It’s an excellent option for many men thought to have slow-growing cancers. But we show here that some men thought to be candidates for active surveillance based on conventional biopsies really are not good candidates.”

How: Marks and his team identified 113 men enrolled in the UCLA active surveillance program who met the criteria for having low-risk cancers based on conventional biopsies. Study volunteers underwent an MRI to visualize the prostate and any lesions. That information was then fed into the Artemis device, which fused the MRI pictures with real-time, three-dimensional ultrasound, allowing the urologist to visualize and target lesions during the biopsy.

“Prostate cancer is difficult to image because of the limited contrast between normal and malignant tissues within the prostate,” Marks said. “With the Artemis, we have a virtual map of the suspicious areas placed directly onto the ultrasound image during the biopsy. When you can see a lesion, you’ve got a major advantage of knowing what’s really going on in the prostate.”

Of the 113 volunteers enrolled in the study, 41 men — or 36 percent — were found to have more aggressive cancer than initially suspected, meaning they were not good candidates for active surveillance. The findings should result in a re-evaluation of the criteria for active surveillance, Marks said.

“We are hesitant now to enroll men in active surveillance until they undergo targeted biopsy,” Marks said. “Fusion biopsy will tell us with much greater accuracy than conventional biopsy whether or not they have aggressive disease.”

“For men initially diagnosed with low-risk prostate cancer, MRI-ultrasound confirmatory biopsy including targeting of suspicious lesions seen on MRI results in frequent detection of tumors,” the study states. “These data suggest that for men enrolling in active surveillance, the criteria need be re-evaluated to account for the risk inflation seen with targeted prostate biopsy.”

On the other hand, Marks said, for men with a negative targeted biopsy, a degree of reassurance is provided that is much greater than that offered by the older, blind biopsy method. I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

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Reference: University of California, Los Angeles (UCLA), Health Sciences. “‘Low-risk’ prostate cancer often not low-risk when targeted biopsy is used.” ScienceDaily. ScienceDaily, 19 May 2014. <www.sciencedaily.com/releases/2014/05/140519084555.htm>.

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