Initial prostate biopsies may be more accurate at academic centers

By Lisa Rapaport Men may get more accurate prostate cancer biopsies at an academic medical center than at a community hospital, say Canadian researchers. The study focused on men diagnosed with low-risk prostate cancer based on the results of initial biopsies. These men are typically monitored by doctors but don’t get treatment right away because their tumors are usually small and slow-growing. If the tumors do turn more risky, they’re reclassified, and researchers found that tumors biopsied at non-academic facilities, such as community hospitals, were much more likely to be reclassified than those taken at a major medical center. “Men having an external initial biopsies were 3-4 times more likely to have grade or volume reclassification,” said lead author Dr. Lih-Ming Wong of the surgical oncology department at Princess Margaret Cancer Centre at the University of Toronto. The grade of cancer indicates how quickly it is growing, and the volume is the percentage of the prostate taken up by the tumor, Wong explained. Typically, when these are reclassified, men become more likely to need treatment. Wong’s team analyzed results from follow-up biopsies done at Princess Margaret for 375 men being monitored with so-called active surveillance, but not yet treated. They found that 13.8 percent of men who had the first biopsy done at the hospital were reclassified as high-risk, compared with 26.8 percent of the patients initially biopsied elsewhere. The biopsies in the study were done using a rectal ultrasound to help the doctor see where to remove tissue samples that appear abnormal. Under a microscope, normal cells appear small, uniform in size, and tightly packed together. As tumors grow, the cells become larger, more haphazard in size and farther apart. Doctors determine the risk of prostate cancer based in part on how many tissue samples contain abnormal cells, what proportion of the prostate tissue overall is malignant and how aggressive the growth is based on the appearance of the cells under a microscope. The study found that 19.7 percent of men initially evaluated elsewhere were reclassified from “low-risk” to “aggressive” tumor growth on the second biopsy, compared with 7.5 percent of men who got their first biopsy at the academic medical center. In addition, 20.3 percent of men first tested elsewhere were reclassified as high-risk because at least half of the tissue sampled was malignant, compared with 8.5 percent of the men biopsied both times at the Princess Margaret Cancer Centre, the researchers report in Prostate Cancer and Prostatic Disease. Some men waited longer than the recommended six months to get a second biopsy, leading them to be reclassified as high-risk because of the delay. Still, the findings highlight the importance of seeking out the right specialists to do the original biopsy. Men should go where the most procedures are done, which is often an academic medical center, Wong said. While patients can take a biopsy report to another doctor for a second opinion, and physicians at academic medical centers can sometimes review digital copies of a report, Wong advised against this. "Digitalizing pathology slides and clinical information would speed the process of providing a second opinion, but this doesn’t solve the problem of an inadequate biopsy if the original data collection is flawed," Wong said. If it’s at all possible, men should travel to an academic medical center for a biopsy, especially if they have already found an abnormal result at a community hospital closer to home, said Dr. Jay Ciezki at the Cleveland Clinic's Taussig Cancer Institute in Ohio. Even though the study was done at a single site in Toronto, the findings should be applicable in the U.S. because the difference in expertise between academic medical centers and local hospitals is widespread, said Ciezki, who was not involved in the research. One shortcoming of the study, however, is the type of biopsy involved, said Dr. Leonard Marks, a urologist at the University of California, Los Angeles Medical Center and Jonsson Comprehensive Cancer Center. It relied on conventional ultrasound-guided biopsies, which is much less accurate than the targeted biopsies guided by MRI images used at UCLA and a growing number of other academic medical centers, said Marks, who was not involved in the study. In a recent study of his own, Marks and his colleagues found that 36 percent of men put on active surveillance after a conventional biopsy were reclassified as high risk after a second biopsy using an MRI was performed at UCLA. "Ultrasound-guided biopsy is blind; it doesn't see cancer," Marks said. "If you do it the modern way using MRI, the imaging tells you where to go with the needle to get the tissue you need. That MRI imaging is sophisticated and probably wouldn't be too widely available outside of academic medical centers." SOURCE: http://bit.ly/1FXXEcq Prostate Cancer and Prostatic Disease, online December 9, 2014.