There have been many studies on breast cancer and how to treat the disease, but new research suggests some cases of invasive breast cancers may regress on their own -- and never need treatment.
The study, published Monday in the journal Archives of Internal Medicine, suggested breast cancer screening may be leading to over diagnosis of cancer.
Doctors from Norway followed a group of women between the ages of 50 and 64. One group had mammograms every two years -- the other had one mammogram at the end of the six-year study.
Breast cancer rates were about 22 per cent higher among women who had multiple mammograms.
Since the women were similar in all other ways, the researchers concluded the mammograms were picking up breast cancers that the immune system would fight and the tumours would disappear.
"Women who undergo mammography screening will sometimes be labelled with breast cancer when in fact they really don't have a lesion that will behave in the nasty breast cancer we all fear," says University of Toronto's Dr. Cornelia Baines.
The results could cause a lot of debate because researchers will never know for sure if the tumours spontaneously vanished. To prove the results, doctors would have to let some women go untreated -- which could be life-threatening and unethical.
With reports from The Canadian Press and CTV British Columbia's Dr. Rhonda Low
