Doctors cling to comfortable, widely used medical practices, even if they’re no longer particularly effective, right? A new study disputes that popular perception. In the case of a particular breast cancer treatment at least, many physicians quickly abandoned it after a clinical trial showed it was ineffective.
The study, published in the July issue of the journal Health Affairs, tracked treatment patterns before and after the results of a major clinical trial that examined the effectiveness of removing lymph nodes near the breast to prevent the spread of cancer.
Prior to 2011, the procedure, called axillary lymph node dissection, was commonly performed if a woman with a small, early-stage tumor had a lumpectomy, and a biopsy subsequently found cancer in one or more of the sentinel lymph nodes that receive fluid directly from the breast. The axillary dissection removed at least eight lymph nodes, and often many more, eliminating sites where diseased cells might lurk. But it frequently caused side effects as well, such as a fluid build-up in the arm called lymphedema.
The clinical trial assigned 891 women who had lumpectomies and had one or two positive sentinel lymph nodes to either receive axillary dissection or no additional treatment. Having the procedure, the study found, didn’t improve patient outcomes. Five-year survival rates were essentially the same: 91.8 percent for women who had axillary dissections versus 92.5 percent for those that didn’t undergo the procedure, who had the added benefit of avoiding side effects from the lymph node dissection.
The trial results were presented at a meeting of clinical oncologists in 2010 and published in the Journal of the American Medical Association in 2011. The Health Affairs study used two large cancer registry databases to track whether physician treatment changed after the trial data was made public.
The shift was dramatic. Between 2008 and 2012, the proportion of patients who met the clinical trial criteria who underwent the procedure declined by more than 50 percent, or 32.6 percentage points.
Part of the explanation for the decline may lie in how breast cancer differs from other types of cancer or diseases, said David E. Howard, an associate professor of health policy and management at Emory University and the study’s lead author.
“Breast cancer patients are very activated,” he said, adding that they track new evidence and treatments closely. “This puts additional pressure on physicians to look at evidence.”
In addition, the trial results were significant for a very specific group: cancer surgeons who specialize in breast procedures. It’s likely easier for physicians with a narrow specialty to keep up with the evidence than it is for someone who’s an internist, for example, dealing with a wide range of conditions, from diabetes to heart disease, Howard said.
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