Such uncertainty about a cancer operation that has been in use for 30 years is “a shame,’’ said Dr. Laurence E. McCahill, the first author of the study, and a surgeon and assistant director of the Lacks Cancer Center in Grand Rapids, Mich.
Dr. Monica Morrow, the chief of breast surgery at Memorial Sloan-Kettering Cancer Center in New York, said, “It is getting to be the time for leaders in radiation oncology and surgery to get together and make a consensus statement that could help to guide their membership.’’
McCahill’s study, published online yesterday by the Journal of the American Medical Association, is based on the medical records of 2,206 women who had lumpectomies at one of four hospitals in different parts of the country. Overall, 22.9 percent had more than one operation.
Nearly half the repeat operations were done in women whose pathology reports did not indicate that any stray cancer cells had been left behind, meaning that the operations probably did not help the patients. More disturbingly, 14 percent of patients who had evidence of cancer left behind did not have another operation, for unknown reasons.
Rates of repeat surgery varied by surgeon, from zero to 70 percent, and by hospital, from 1.7 percent to 20.9 percent. Differences in the patients did not account for most of the variation, although very thin women, who tend to have small breasts, were more likely to need second operations. Surgeons say that is because they try hard to remove as little tissue as possible from small breasts, for cosmetic reasons.
“The number of operations women undergo definitely depends on where you’re treated and even to a greater level on which surgeon you see,’’ McCahill said. “We put the math behind it and said, this is a lot of second operations that maybe don’t make a difference.’’
A major reason for the variation is that there is no consensus among surgeons about how big a rim or “margin’’ of healthy tissue should be taken out when a cancer is removed. Surgeons try to cut cleanly around a tumor and remove enough of a margin to ensure that they excised all the cancer.
