In the past several years, there have been major, even bitter, controversies amongst doctors’ groups in the USA regarding “best practices” for early detection of breast cancer.
The controversy became much more intense following the recent publication of the Canadian National Breast Screening Study that concluded mammograms might not be so helpful after all.
But this study has been called “incredibly misleading” and “deeply flawed” by the American College of Radiology, and Dr. Daniel Kopans, a senior radiologist at one of the top hospitals in the U.S, the Massachusetts General Hospital, said “it would be an outrage for women if access to screening was curtailed” because of the results of this study.
Yet the doctors and researchers on the other side of the controversy are just as adamant. The lead author of the study, Dr. Anthony Miller of the University of Toronto, said “We found absolutely no benefit in terms of reduction of deaths from the use of mammography”.
And Dr. H. Gilbert Welch from the Dartmouth College School of Medicine, and author of the book “Overdiagnosis: Making People Sick in the Pursuit of Health” says that “mammography was oversold, that its benefits were exaggerated and its harms were kind of downplayed”.
The Canadian National Breast Screening Study, which you can read here in the British Medical Journal, involved nearly 90,000 women aged 40 to 59, and spanned 25 years. The researchers divided the women into two groups at the beginning of the study. Half the women had only yearly breast exams by trained professionals, and the other half had breast exams as well as yearly mammograms (for the first five years of the study).
The results showed that the women who had only the breast exams, without the mammograms, had the same risk of dying from breast cancer over the 25-year period as the women who had both the breast exams and yearly mammograms. So the researchers concluded in their editorial titled “Too much mammography” that “the rationale for screening by mammography be urgently reassessed by policy makers.”
One argument that mammography may not improve long-term survival statistics is that, yes, mammograms do detect early cancers, but many cancers found on mammography are so small and would grow so slowly, that over the lifetime of that particular woman, they would never grow enough to cause problems.
But it’s hard for doctors to know which tiny cancers found on mammography will grow and cause problems, and which will stay small and “insignificant”. So when a possible cancer is seen on mammography, no matter how small, doctors feel obliged to do further biopsies, which, if positive, will lead to further treatments, including possible surgery and breast removal.
Plus there is the issue of “false positives” from mammograms. This is the situation where a woman is told the mammogram shows a probable cancer, but then a biopsy is done and shows no cancer. False positives are not uncommon, and each time it happens, most women go through a period of high stress and worry (as well as additional procedures and expense) until the final result is given. Further, some experts worry that yearly mammograms done over many years might themselves contribute to causing a cancer, especially when mammograms are started at an early age.
This is a hugely complex and controversial topic, and we certainly don’t have any answer for you here, but you deserve to know about the topic. Talk to your own doctor and see what he or she says. Better yet, also show this post to your doctor, and ask him to contact us to write a guest post here in Mais Saúde.
See also in ProcuraMed:
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