Mammography May Help Detect More Than Just the Presence of Breast Cancer
Feb. 3, 2000 (Eugene, Ore.) -- By using mammograms, an international team of researchers believes it has found a way to identify certain small breast cancers that are far more dangerous than other small breast cancers.
Independent observers praise the team for coming up with a very interesting new theory about breast cancer, but warn that far more research is needed.
Most women with breast cancers detected at an early stage do well, but a small percentage do not. The researchers reviewed data from mammograms on breast tumors ranging from 1 to 14 mm in size. One particular form of breast cancer, which they say has "casting-type calcifications," can be identified by mammogram.
This form of cancer has calcium deposits that form a branching, treelike pattern along the ducts in the breast, essentially forming a cast of the duct. In the United States they are known as "fine linear branching calcifications." There are other types of calcifications that are seen with breast cancer.
The researchers found that women with cancers with this branching pattern had a much higher death rate than women with other tumors of a similar size. Among women with the smallest tumors, 1-9 mm in size, only 14% had casting-type calcifications, but they accounted for 73% of all breast-cancer deaths in the group. The 20-year survival rate of women with 1-14 mm tumors with casting-type calcifications was 55%; about 95% of women with tumors 1-9 mm with no casting-type calcifications lived that long.
If these findings are confirmed in other studies, it would mean women with casting-type calcifications in early breast cancer should receive more aggressive treatment, including chemotherapy. Possibly they should also receive more aggressive surgery, with a wider margin around the tumor, but this is controversial.
"We may have a marker for poor prognosis in breast cancers smaller than 15 mm. We may also have a way to identify the subset of cases that require very aggressive therapy, and those that do not," says one of the researchers, Robert Smith, PhD. "We primarily concluded this is important enough to ask others to verify these findings and to consider prospective studies that would evaluate their true implications." Smith is the director of cancer screening at the American Cancer Society and co-author of the paper.
Daniel Kopans, MD, tells WebMD, "This is a very interesting observation and could have potentially important significance for treatment. It will take a while to find out whether this is a real observation, or an artifact of the way the data were examined, or just a fluke." Kopans, who was not involved in the study, is a professor of radiology at Harvard Medical School. He is also director of breast imaging at Massachusetts General Hospital in Boston.