WASHINGTON (AP) _ Doctors who perform the most mammograms find more cancer and order fewer biopsies, according to a study that compared the X-ray reading skills of British and American physicians.
Dr. Laura Esserman of the University of California said Tuesday that a case-by-case comparison between U.S. physicians and British doctors, who on average read far more X-ray breast films, found that experience paid off in a big way for the patients.
``It's not too surprising,'' said Esserman, the first author of a study in the Journal of the National Cancer Institute. ``People who are more experienced are better _ they find more cancer and biopsy less frequently.''
In the study, the researchers tested the ability of four groups of radiologists to analyze the same 60 mammography films that contained 13 proven cancers.
The test involved 194 mammographers from the United Kingdom and 39 American radiologists. The British doctors typically evaluate about 5,000 breast films, or more than 400 a month. The U.S. doctors were divided into three groups: 18 high-volume doctors who evaluate 301 or more films monthly; 22 medium-volume practitioners who view between 101 and 300 films monthly; and 19 low-volume doctors who see 100 or fewer films a month.
Esserman said the British doctors evaluating the films had an accuracy record of 78.5 percent, which she said was statistically equal to the high-volume American doctors, who were at 75.6 percent.
For medium-volume American practitioners the accuracy rate was 70.2 percent, while for the low-volume American doctors the rate was 64.8 percent.
A lower accuracy, said Esserman, meant that more patients had unnecessary biopsies of breast tissue and that more cancers went undetected.
She said that in the United States, only 10 percent to 20 percent of ordered biopsies end up actually detecting cancer. In the United Kingdom, Esserman said, that cancer is detected in about 40 percent of all biopsies. This means that the British doctors were able to more nearly accurately spot the cancers on X-ray films and order appropriate biopsies, said Esserman.
In an editorial in the journal, Dr. J. G. Elmore of the University of Washington School of Medicine and Dr. P. A. Carney of the Dartmouth Medical School said the Esserman study ``is a vital first step in improving our understanding'' in learning why there is such a variation in interpreting mammography from country to country.
They noted that cultural differences in the United States, such as financial incentives and fear of malpractice lawsuits, may affect the increased number of biopsies ordered by American doctors. These are problems that would not be corrected by requiring more mammography practice by the U.S. doctors, they said.
``Practice probably does improve accuracy, but it may not make us perfect,'' Elmore and Carney said.