A study released today in the Journal of the National Cancer Institute gives me a chance to bring up the phenomenon of a guideline that gets cemented into place as a hospital quality measure even if the premise behind it is controversial or shaky. The study shows that almost two thirds of hospitals fall short of such a standard that took effect last year: A minimum of 12 lymph nodes should be cut out and sent to the pathology lab in all patients who have a section of cancerous colon removed.
No surgeon challenges the absolute necessity to put lymph node tissue under the microscope to see whether cancerous cells have spread beyond the colon or other organ. The guideline, moreover, is based on studies that seem to show a clear relationship between long-term survival after such surgery and the number of nodes excised. The logical explanation is that the more nodes examined, the greater the chance of finding at least one that is positive for cancer, which triggers aggressive treatment involving radiation and chemotherapy. Therefore, it is important to look at a large number of nodes to maximize the odds of finding an elusive positive one.
"Some medical oncologists feel so strongly about this," says surgeon Karl Bilimoria, the study's chief investigator and a research fellow at the American College of Surgeons, "that they say, 'If there are fewer than 12 nodes, we can't be certain there is no cancer, and we will give them chemotherapy.' "
But John Birkmeyer, a professor of surgery at the University of Michigan Hospitals and Health Centers, says a 12-node threshold has no place as a quality measure. He calls it "distracting" and the evidence supporting it "simplistic." A longtime student of the factors that influence hospital performance, Birkmeyer is a coauthor of a study published last November in the Journal of the American Medical Association that found no relationship between long-term survival of colon cancer patients and the number of lymph nodes taken to be examined. Far more important were a hospital's number of such surgeries and whether it was a designated National Cancer Institute Comprehensive Cancer Center.
"If you were giving a patient a short list of essential variables linked with colon cancer survival," says Birkmeyer, "I would put four things on that list—the procedure volume for the hospital and the surgeon" of roughly 50 and 20 per year respectively, "whether the surgeon is board certified in colorectal cancer surgery, and whether the hospital is an NCI CCC. Node counts wouldn't be anywhere on my list."
As a quality indicator, he says, node count doesn't work. Yet now that the standard has been set, hospitals and surgeons could be financially penalized, be removed from insurers' networks, and suffer other consequences if they don't meet it. My question is, why wasn't it studied further before it was put out?