As a rule, it's a good idea to have your surgery done by someone who gets a lot of practice in the procedure. For example, breast cancer patients are likely to survive longer if they're operated on by surgeons who perform breast cancer surgery at least 15 to 30 times a year. But researchers at the Medical College of Wisconsin in Milwaukee say most breast cancer surgeries are done by surgeons who only rarely perform them.

What the researchers wanted to know: Who performs most breast cancer surgery—surgeons who cut out breast tumors all the time or surgeons who handle breast tumors only occasionally?

What they did: The researchers used data from the National Cancer Institute and Medicare to identify a cohort of more than 8,000 women who had breast cancer surgery in 1994 or 1995 in Connecticut, Iowa, New Mexico, Utah, Atlanta, and Detroit. Information on the 987 physicians who operated on them was linked up with a database run by the American Medical Association.

What they found: More than half of surgeons did six or fewer breast cancer operations on Medicare patients every two years. (Medicare patients represent about half of breast cancers, so the researchers figure that means Medicare patients were about half of the surgeons' business—which would mean those surgeons did a total of six or fewer breast cancer surgeries a year.) Only 10 percent of patients had their surgery done by someone who performed more than 30 breast cancer operations on Medicare patients in two years—the level that two earlier studies found to reduce mortality. Almost half had their surgery performed by a physician who did it fewer than 12 times in two years. The well-practiced surgeons seemed to give better care, too: They were more likely to test for hormone receptors and to use methods that conserve the breast.

What the study means to you: There's pretty good evidence that it's safer to have a surgeon who does your kind of surgery often, but this study shows that most surgeons who perform breast cancer surgery don't do it very often.

Caveats: The researchers used Medicare data, so they don't know how many operations these surgeons were doing on non-Medicare patients.

Find out more: The University of California–Irvine Medical Center has advice on choosing a surgeon.

Read the article: Neuner, J. M., et al. "Decentralization of Breast Cancer Surgery in the United States." Cancer. Sept. 15, 2004, Vol. 101, No. 6, pp. 1323-1329.

Abstract online: www3.interscience.wiley.com