Prostate Cancer News
MRI IMPROVES PROSTATE CANCER BIOPSY ACCURACY, STUDY FINDS
New technology spots more aggressive cancer, but fewer low-risk cases
By Dennis Thompson
Jan. 27, 2015 (HealthDay News) — Prostate biopsies that combine MRI technology with ultrasound appear to give men better information regarding the seriousness of their cancer, a new study suggests.
The new technology — which uses MRI scans to help doctors biopsy very specific portions of the prostate — diagnosed 30 percent more high-risk cancers than standard prostate biopsies in men suspected of prostate cancer, researchers reported.
These MRI-targeted biopsies also were better at weeding out low-risk prostate cancers that would not lead to a man’s death, diagnosing 17 percent fewer low-grade tumors than standard biopsy, said senior author Dr. Peter Pinto. He is head of the prostate cancer section at the U.S. National Cancer Institute’s Center for Cancer Research in Bethesda, Md.
These results indicate that MRI-targeted biopsy is “a better way of biopsy that finds the aggressive tumors that need to be treated but also not finding those small microscopic low-grade tumors that are not clinically important but lead to overtreatment,” Pinto said.
Findings from the study are published in the Jan. 27 Journal of the American Medical Association.
Doctors performing a standard biopsy use ultrasound to guide needles into a man’s prostate gland, generally taking 12 core samples from predetermined sections.
The problem is, this type of biopsy can be inaccurate, said study lead author Dr. Mohummad Minhaj Siddiqui, an assistant professor of surgery at the University of Maryland School of Medicine and director of urologic robotic surgery at the University of Maryland Marlene and Stewart Greenebaum Cancer Center in Baltimore.
“Occasionally you may miss the cancer or you may glance the cancer, just get an edge of it, and then you don’t know the full extent of the problem,” Siddiqui said.
In a targeted biopsy, MRIs of the suspected cancer are fused with real-time ultrasound images, creating a map of the prostate that enables doctors to pinpoint and test suspicious areas.
Prostate cancer testing has become somewhat controversial in recent years, with medical experts debating whether too many men are being diagnosed and treated for tumors that would not have led to their deaths. Removal of the prostate gland can cause miserable side effects, including impotence and incontinence, according to the U.S. National Cancer Institute. But, even if a tumor isn’t life-threatening, it can be psychologically difficult not to treat the tumor.
To test the effectiveness of MRI-targeted biopsy, researchers examined just over 1,000 men who were suspected of prostate cancer because of an abnormal blood screening or rectal exam.
The researchers performed both an MRI-targeted and a standard biopsy on all of the men, and then compared results.
Both targeted and standard biopsy diagnosed a similar number of cancer cases, and 69 percent of the time both types of biopsy came to exact agreement regarding a patient’s risk of death due to prostate cancer.
However, the two approaches differed in that targeted biopsy found 30 percent more high-risk cancers, and 17 percent fewer low-risk cancers.
“You’re missing low-risk cancer. This is the type of cancer where this person certainly would have lived their whole life and died of something else,” Siddiqui said.
An MRI is great for guiding doctors to serious cancers, but is not able to detect lesions smaller than 5 millimeters, said Dr. Art Rastinehad, director of focal therapy and interventional urological oncology and an associate professor of urology and radiology at Icahn School of Medicine at Mount Sinai in New York City.
“MRI’s greatest weakness is also its greatest strength when it comes to prostate cancer,” ignoring low-risk tumors while accurately directing a biopsy to potentially lethal cancers, Rastinehad said. “This study does lay the foundation for a possible paradigm shift in the way we screen men for prostate cancer,” he added.
Clinical trials still are needed to show whether MRI-targeted biopsy will save lives or reduce future recurrence of cancer, JAMA Associate Editor Dr. Ethan Basch argued in an editorial accompanying the study. Basch is also director of cancer outcomes research at the University of North Carolina at Chapel Hill.
“A new test should not be widely adopted in the absence of direct evidence showing benefits on quality of life, life expectancy, or ideally both,” wrote Basch.
Another open question also remains — whether the new technology, which requires an MRI for each suspected case of prostate cancer and new equipment to fuse the MRI with an ultrasound scan, would be worth the extra expense.
Pinto believes the new technology might actually save money in the long run, by reducing overtreatment.
“We have to be very thoughtful, especially where health care dollars are scarce, to bring in technology that will not only help men but will be cost-efficient,” he said. “That work has not been done completely, although some studies imply this technology may decrease considerably the number of unnecessary biopsies performed every year, and so could help control costs.”
There’s more on prostate cancer and radiation treatment at the American Cancer Society.
NEW URINE TEST FOR PROSTATE CANCER AVAILABLE; UNLIKE PSA TEST, IS ULTRA-SPECIFIC FOR PROSTATE CANCER
September 25, 2013 — A new urine test for prostate cancer that measures minute fragments of RNA is now commercially available to men nationwide through the University of Michigan MLabs. The new test—Mi-Prostate Score (MiPS)—improves the utility of the PSA blood test, increases physicians’ ability to pick out high-risk prostate tumors from low-risk tumors in patients, and may help tens of thousands of men avoid unnecessary biopsies.
The MiPS test incorporates blood PSA levels and two molecular RNA markers specific for prostate cancer in one final score that provides men and their doctors with a personalized prostate-cancer risk assessment.
Drawbacks of stand-alone PSA testing for prostate cancer
•The prostate specific antigen (PSA) is a protein made by the prostate. For decades the PSA test has been used as a marker for the presence of prostate cancer in men—high or rising levels of PSA in blood may indicate the presence of a prostate tumor. However, the PSA test is a non-specific test for prostate cancer. That is, non-cancerous conditions such as an enlarged or inflamed prostate can cause elevations in PSA levels. And even when PSA levels rise above what has routinely been considered a trigger level (4.1 ng/ml in the blood) indicating the need for a needle biopsy to check prostate tissue for signs of cancer, less than half of those biopsies find cancerous cells. In addition, up to 44 percent of PSA-triggered biopsies find cancer cells that are non-lethal, indolent prostate cancer cells. Indolent prostate cancer is highly unlikely to shorten the lifespan of a man. However, treatment with surgery or radiation can carry significant risk of side effects such as incontinence or sexual dysfunction.
Improving upon the PSA test
•The limited reliability of the PSA test, and its lack of specificity for prostate cancer, has led to sharp disagreement over the use of the PSA test as a routine health screening measure for men of a certain age. What everyone does agree upon is the need for better markers of prostate cancer. To date there are no perfect biomarkers that identify only high-risk prostate cancer. But each year progress is made toward such a goal. Today, the University of Michigan’s Department of Pathology MLabs will begin offering the MiPS urine test that is ultra specific for prostate cancer. The MiPS test scans urine samples for two molecular markers that are distinct to prostate cancer. One marker is a snippet of RNA made from a gene (PCA3) that is overactive in 95 percent of all prostate cancers. The second marker is RNA that is made only when two genes (TMPRSS2 and ERG) abnormally fuse. The presence of this fusion RNA in a man’s urine is ultra specific for prostate cancer.
An ultra-specific test for prostate cancer
•Dr. Scott Tomlins, MD, PhD, is an assistant professor of pathology and urology at the University of Michigan and a Safeway-Prostate Cancer Foundation Young Investigator. Tomlins co-discovered what is now commonly known as the TMPRSS2:ERG fusion. “The evidence shows that if TMPRSS2:ERG RNA is detectable at high levels in urine, a man likely has prostate cancer, whether or not his biopsy is positive for cancer,” said Tomlins. (Because biopsies typically sample less than 1 percent of the prostate gland, cancers can be missed, even high-grade cancers.)
A commercial urine test (PROGENSA PCA3) for PCA3, developed and marketed by the California-based biotech company Gen-Probe, gained FDA approval in 2012 for use in men who are considering repeat biopsy after an initially negative result. While a welcome development, research shows that the new urine test offered by MLabs that measures both PCA3 and TMPRSS2:ERG should improve a doctor’s ability to stratify men suspected of having prostate cancer. In a study published in Science Translational Medicine, Tomlins and colleagues found the highest rates of cancer in men with the highest levels of TMPRSS2:ERG and PCA3 in their urine. The men in the study were stratified into three groups based upon the levels of TMPRSS2:ERG and PCA3 in their urine: low, intermediate and high levels, or scores. Cancer was diagnosed in each of the groups respectively: 21%, 43%, and 69%. High-grade prostate cancer, defined in the study as a Gleason score greater than 6, also occurred at different frequencies in the three groups with 7%, 20%, and 40% diagnosed in each group respectively.
Other research has shown that the two-marker urine test is more effective than the PSA test alone, or PSA testing that’s incorporated into a commonly used online tool (the Prostate Cancer Risk Calculator), at predicting the presence of prostate cancer.
For additional research results of the MiPS test, how results will be presented to men and their doctors, and other background information, clickhere.
From more information on how to send a specimen, please call MLabs at 800-862-7284 or visit www.mlabs.umich.edu.
The Prostate Cancer Foundation is not endorsing the use of this test or non-use—PCF does not endorse commercial companies or products. The Foundation heartily applauds each research step made toward precision medicine and better biomarkers for prostate cancer that improves the standard of care for patients and leads to less suffering and death from this disease that will affect one in six men in the US. The Safeway Foundation generously provided unrestricted funding to the Prostate Cancer Foundation for biomarker research that funded this work. The Safeway Foundation also provided PCF-Young Investigator funding to Dr. Tomlins. The Prostate Cancer Foundation is the world’s largest philanthropic source of support for accelerating the most promising research for better treatments and cures for prostate cancer. To learn more about PCF go to www.pcf.org.