Study: Mammograms Don't Reduce Death
Wednesday, September 20th 2000, 12:00 am
By: News On 6
WASHINGTON (AP) â€” A competent physical exam for women over the age of 50 may be as effective in reducing the risk of breast cancer death as an annual screening that includes a mammogram, a new study suggests.
The study, published Wednesday in the Journal of the National Cancer Institute, suggests that women who are unable or unwilling to get mammograms can protect themselves equally well from breast cancer death by getting thorough annual physical breast examinations, said Dr. Cornelia J. Baines of the University of Toronto.
Some cancer experts disputed the results of the study, saying that worldwide research has shown that regular mammograms, as recommended by many U.S. health organizations, are an essential part breast cancer survival.
Baines said she is not suggesting women should stop mammograms because they clearly can reduce cancer deaths.
However, she said, ``if you happen to be among those women who can't afford mammography or don't like it and the pain and tenderness associated with it, go get a good clinical breast cancer and you will be protecting yourself against breast cancer death.''
Dr. Robert A. Smith, director of cancer screening at the American Cancer Society, disputed the conclusion, noting that of seven similar studies in Europe and North America, the Toronto study is the only one to not show a clear survival advantage for mammography.
``It stands out as being the only trial that at its conclusion the groups that received mammography had higher rates of advanced breast cancer than the groups not offered mammography,'' said Smith. ``The problems with the Canadian study are well known.''
He said there are unresolved questions about the way patients were selected and about the quality of the X-ray mammography techniques used.
Smith said that the American Cancer Society will continue to recommend that women over the age of 40 get annual mammography examinations. The American Medical Association has endorsed this recommendation.
The National Cancer Institute recommends that women over 40 get a mammogram exam ``every one to two years,'' said Dr. Daniel C. Sullivan, head of the biomedical imaging program at the institute.
Both Smith and Sullivan said that the advantage of mammography is that it spots smaller tumors, which means disease is detected earlier.
Sullivan said that earlier detection with mammography may mean that the cancer can be treated with less radical therapy, such as a small incision to remove a lump, followed by radiation. Larger tumors must be treated by mastectomy, removal of the whole breast, followed by chemotherapy or radiation.
Baines agreed that tumors detected by physical examination alone were larger than those found by mammography.
``But, in terms of avoiding death by breast cancer,'' she said, ``it doesn't seem to have added any benefit to have the mammograph detecting earlier cancer.''
In the Toronto study, 39,405 women volunteers, aged 50 to 59, were divided into two groups â€” one that periodically received both mammography and careful physical examinations, and a second group that received physical examinations only. Both groups were given training in breast self examination, or BSE, but Baines said it is not clear if this played a role in the results. The patients were enrolled between 1980 and 1985 and followed for an average of 13 years.
The initial screening found 267 invasive (spreading) breast cancers in the mammography group and 148 in the physical-exam only group.
By the end of 1993, the different screening techniques had detected about an equal amount of cancer. There were 622 invasive tumors and 71 in-place tumors in the mammography group, and 610 invasive tumors and 16 in-place tumors in the physical exam-only group.
The number of breast cancer deaths also was nearly equal: 107 for the mammography group and 105 deaths in the other group.
The bottom line, said Baines, is that ``the addition of annual mammography screening to physical examination has no impact on breast cancer survival.''
Baines, however, noted that all the patients in the study received highly competent physical breast examinations. Other studies have shown that ``a lot of work has to be done to improve the competence of the breast physical exams that are now being done,'' she said.
On the Net:
Journal of the National Cancer Institute: http://jnci.oupjournals.org/