Study Reveals More Than One-Third of Patients With ‘Low-Risk’ Prostate Cancer on Conventional Biopsy Have More Aggressive Tumors on Targeted Biopsy

Key Points

  • The targeted biopsy method is performed by combining magnetic resonance imaging with real-time, three-dimensional ultrasound.
  • Of 113 volunteers enrolled in the active surveillance program who met the criteria for having low-risk cancers based on conventional biopsy, 41 men (36%) were found to have more aggressive cancer than initially suspected.
  • The findings should result in a reevaluation of the criteria for active surveillance, the authors said.

According to a new study by researchers at the University of California, Los Angeles, selection of men for active surveillance for prostate cancer should be based not on conventional biopsy, but on a new, imaging-guided targeted prostate biopsy. The new biopsy method is now a routine part of the UCLA active surveillance program. The study findings were published in The Journal of Urology.

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 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 Leonard Marks, MD, Professor of Urology and Director of the UCLA Active Surveillance Program. “It’s touted as the best course for many men thought to have slow-growing cancers. But we show here that many men thought to be candidates for active surveillance based on conventional biopsies really are not good candidates.”

Study Details

Dr. 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,” Dr. 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 (36%) were found to have more aggressive cancer than initially suspected.

Call to Reevaluate Criteria for Active Surveillance

The findings should result in a reevaluation of the criteria for active surveillance, Dr. Marks said. “We are hesitant now to enroll men in active surveillance until they undergo targeted biopsy,” Dr. Marks said. “Fusion biopsy will tell us with much greater accuracy than conventional biopsy whether or not they have aggressive disease.”

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.

“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 authors stated. “These data suggest that for men enrolling in active surveillance, the criteria need to be reevaluated to account for the risk inflation seen with targeted prostate biopsy.”

On the other hand, Dr. 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.

Dr. Marks is the corresponding author for The Journal of Urology article.

The study was funded by the National Cancer Institute, the Beckman Coulter Foundation, Jean Perkins Foundation, and the Steven C. Gordon Family Foundation.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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