Regular mammograms for younger women could save their lives as a new analysis has found that most deaths from breast cancer occur in those who do not receive them.
Health on Female First
The use of mammograms to prevent breast cancer deaths has been controversial, especially after the United States Preventive Services Task Force proposed in 2009 to limit screening to women aged 50 to 74 years.
Studies show varying benefits, and advances in treatment may have diminished the importance of early detection.
Blake Cady, MD, Professor of Surgery (emeritus) of Harvard Medical School in Boston, and his colleagues set out to provide more definitive information on the value of mammography screening through a technique called “failure analysis.”
“The biological nature of breast cancer in young women is more aggressive, while breast cancer in older women tends to be more indolent. This suggests that less frequent screening in older women, but more frequent screening in younger women, may be more biologically based, practical, and cost effective,” said Dr. Cady.
Among 609 confirmed breast cancer deaths, 29% were among women who had been screened with mammography, while 71% were among unscreened women. Of all breast cancer deaths, only 13% occurred in women aged 70 or older, but 50% occurred in women under age 50. Among women diagnosed with breast cancer, those who died of the disease were a median of 49 years old at diagnosis; for those dying of any other cause, the median age at diagnosis was 72 years.
Dr Caitlin Palframan, from leading charity Breakthrough Breast Cancer, says: “Although interesting, this study does not tell us anything new to suggest routine breast screening should be offered to women under 50. In fact, it has some serious limitations. Breast cancer is less common in women under 50 and, whilst we know that screening can detect cancer early, it does have risks. Before we could consider extending the routine screening age we need to be sure that the benefits outweigh these risks in younger women. This study does not explore this important issue.
“Fortunately, England’s national breast screening programme is carrying out a large trial that will look in to whether screening women from the age of 47, instead of 50, is effective. On top of this, women with a faulty BRCA gene, and some others that have a high risk of developing breast cancer, are currently offered routine screening from a younger age. Breakthrough Breast Cancer would like to see the NHS look into extending this to more women at increased risk of developing breast cancer as they are likely to benefit most from additional screening.”
This study also showed a dramatic shift in survival from breast cancer associated with the introduction of screening. In 1969, half of women diagnosed with breast cancer had died by 12.5 years after diagnosis. Among the women with invasive breast cancer in this review who were diagnosed between 1990 and 1999, only 9.3% had died. “This is a remarkable achievement, and the fact that 71% of the women who died were women who were not participating in screening clearly supports the importance of early detection,” said co-author Daniel Kopans, MD, of Harvard Medical School and Massachusetts General Hospital. He added that a number of research articles have inaccurately claimed that screening leads to over diagnosis. “None of these papers have actually looked at individual women but have used registry data, and this has led to false conclusions…This present paper examines each woman as an individual with direct data on who was screened and which women died of breast cancer. It addresses the question from a different and unique perspective."
Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study indicates that regular screening before age 50 should be encouraged.Â
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