Mammograms could reduce the chances of dying from breast cancer by 28 percent, based on a new study.
In 2012, a study in England reported that for every life saved by mammograms, three women are treated for a non-life-threatening cancer.
"Mammograms do provide some benefit, but the problem is the screening is so sensitive it captures tumors without malignant potential," Lars Vatten of the Norwegian University of Science and Technology told the press.
In February 2014, a Canadian study announced the procedure does not lower the risk of dying from breast cancer. This investigation followed subjects for two decades.
Researchers in the latest study examined data stretching over 23 years. Mammograms were offered to several of the women free of charge, and 76 percent of those offered the procedure took part.
"We analyzed data from all women in Norway who were aged 50 to 79 during 1986 to 2009... We compared the rates of deaths from breast cancer among those who were invited to screening... with those who had not been invited to screening before breast cancer was diagnosed," researchers wrote in an article announcing the study.
The study concluded that approximately 368 women are needed to be offered mammograms in order to save one life.
If an abnormal finding is made during a mammogram, follow-up tests could include an ultrasound or MRI. If the results of these tests are not positive, the next step is often a biopsy. These procedures can cost patients mental and physical anguish. Around 80 percent of the time, test results are negative.
Breast cancer deaths have declined in wealthier nations over the last few years and decades. Most of this improvement is driven by advances in treatments. Mammograms allow early detection, and combined with modern medicines, can assist in early cures.
Chemotherapy, radiation and surgeries can have traumatic effects on the human body. In cases where the cure could be worse than the disease, patients and doctors may opt to leave cancer untreated.
"To tell women not to have a mammogram is probably an overreaction but we are becoming more certain screening has significant harms," Russell Harris of the University of North Carolina, author of an editorial accompanying the study.
The Norwegian Research Council funded the study, investigating the effectiveness of government screen programs, including mammograms, on the health of the population of Norway.
During the years 1995 to 2005, the Norwegian mammography screening program was slowly introduced to the nation. A mathematical model was used to correct for the changing ages of women over the years of the study.
Investigation of mammograms and their potential to lower deaths from breast cancer was published in the journal BMJ.
