Combining MRI, ultrasound allows doctors to better spot hidden, often aggressive, tumors
MONDAY, Dec. 10, 2012 (HealthDay News) -- A new, highly targeted form of biopsy could be an advance in prostate cancer care, a new study suggests.
Researchers at the University of California, Los Angeles, say prostate tumors can be diagnosed using "image-guided targeted biopsy" -- the direct sampling of tumors in tissue using both MRI and real-time ultrasound.
The UCLA team say this targeted form of biopsy is much more accurate than conventional "blind" biopsies that do not enable doctors to actually see the tumors. They suggested the new procedure may improve early detection of prostate cancer and result in fewer biopsies overall.
"Early prostate cancer is difficult to image because of the limited contrast between normal and malignant tissues within the prostate," study senior author Dr. Leonard Marks, a professor of urology and director of the UCLA Active Surveillance Program, said in a university news release. "Conventional biopsies are basically performed blindly, because we can't see what we're aiming for. Now, with this new method we have the potential to see the prostate cancer and aim for it in a much more refined and rational manner."
Almost all of the 1 million prostate biopsies performed in the United States every year are performed after a man tests positive for elevated blood levels of prostate-specific antigen (PSA), which can indicate prostate cancer.
One expert not connected to the new study said current biopsy methods have their pros and cons.
"Currently, the diagnosis of prostate cancer occurs through a transrectal ultrasound guided prostate biopsy," said Dr. Warren Bromberg, chief of urology at Northern Westchester Hospital in Mount Kisco, N.Y.
"The advantage of this procedure is that it can be performed with local anesthesia in a urologist's office in less than 10 minutes," he said. "The problem with this method is that approximately 75 percent of men have negative biopsies [and] the cancerous areas are usually not visible. So, multiple biopsies are taken to try to 'find' the cancer, the procedure is usually repeated at some point when the PSA test continues to rise, insignificant cancers are detected as often as significant ones, there is always the fear that a cancer was missed, and there are risks of infection, pain and bleeding."
The UCLA team sought to determine if more targeted biopsy methods could change that. In the study, they actively monitored 171 men with slow-growing prostate cancers or those who had received negative biopsies but maintained persistently high PSA levels, suggesting that a tumor might be present.
The participants first had an MRI to visualize their prostate. That image was sent to a device, called Artemis, that fuses the MRI pictures with real-time, three-dimensional ultrasound. This fusion process allows a urologist to see lesions during the biopsy.
"With the Artemis, we have a virtual map of the suspicious areas placed directly onto the ultrasound image during the biopsy," noted Marks. "When you can see a lesion, you've got a major advantage of knowing what's really going on in the prostate. The results have been very dramatic, and the rate of cancer detection in these targeted biopsies is very high. We're finding a lot of tumors that hadn't been found before using conventional biopsies."
Fifty-three percent of the men involved in the study had prostate cancer, according to the study published online Dec. 10 in The Journal of Urology. Marks and his colleagues also found that 38 percent of the cancers found using targeted biopsy were aggressive tumors -- meaning they more likely to spread and require treatment.
Unlike conventional blind biopsies which can be painful and require men to be placed under general anesthesia and undergo lengthy recoveries, the targeted UCLA biopsies were performed in about 20 minutes in an outpatient clinic setting under local anesthesia, the team said.
"Targeted prostate biopsy has the potential to improve the diagnosis of prostate cancer and may aid in the selection of patients for active surveillance and focal therapy," the study authors wrote.
Another expert said the the new technology has real promise.
"Prostate biopsies have been performed the same way for the past 30 years," said Dr. Louis Potters, chair of radiation medicine at North Shore-LIJ Health System in New Hyde Park, N.Y. "The study from UCLA is evaluating the next step in the evolution of the prostate biopsy. It combines the state-of-the-art MRI which allows clinicians to see inside the prostate with incredible detail."
Potters said the UCLA data matches those from his own institution "that reports improved cancer detection of this technique" compared to traditional biopsy.
"More importantly, the lesions seen on the MRI with a corresponding positive biopsy are associated with a higher grade cancer and increased amount of cancer sampled," he said. "This translates into improved information for the patient, as well as the clinician."
Besides allowing "better visualization" of tumors, "adding the MRI to the ultrasound seems to allow preferential detection of the more life-threatening type of cancer [high-grade], which could reduce the chances that a man would undergo unnecessary treatment," he said.
As for cost, "the overall added cost of the MRI may be offset by the reduced number of biopsy procedures," Bromberg said.
The U.S. National Cancer Institute provides more information on prostate cancer screening (http://www.cancer.gov/cancertopics/pdq/screening/prostate/Patient/page1 ).
SOURCE: Warren Bromberg, M.D., chief, urology, Northern Westchester Hospital, Mount Kisco, N.Y.; Louis Potters, M.D., chair, radiation medicine, North Shore-LIJ Health System, New Hyde Park, N.Y.; University of California, Los Angeles, news release, Dec. 10, 2012