Dec. 6, 2011 — Despite the controversies over mammograms, the bottom line is they still save lives in women aged 50 to 75. A new Dutch study shows the scan reduced the risk of death from breast cancer in this age group by almost half.
Women between 50 and 75 years old who had at least three mammograms in the Netherlands national screening program before they were diagnosed with breast cancer were 49% less likely to die of the disease, according to the study published in Cancer Epidemiology, Biomarkers & Prevention.
“Our program invites women between 50 and 75 for free screening every two years. And that reduces the risk of death from breast cancer,” says researcher Suzie Otto, PhD.
Women aged 70 to 75 benefited the most from mammograms, with an 84% reduction in breast cancer deaths. The screening reduced breast cancer deaths by 39% in women aged 50-69.
Stage IV tumors — defined as invasive breast cancer that has spread beyond the breast to other organs — were also far less frequent in women whose cancer was detected through a mammogram. Among women with breast cancer who had not had mammograms, nearly 30% had stage IV tumors. Only 5% of women whose breast cancer was detected by mammogram had stage IV tumors.
Results May Differ Some in U.S.
Mammograms may not reduce death as significantly in the U.S. because of major differences between U.S. and European screening practices.
However, “these results do make us all feel good about our recommendations for screening women in their 50s and 60s,” says Otis Brawley, MD, chief medical officer of the American Cancer Society. “I wouldn’t take the 49% [study finding] too much to heart, but it does show that screening does save lives.”
The high reduction in death in the Dutch study can be attributed to the efficiency of European screening programs. “It is a well-oiled machine,” Brawley says. “Here, some women go from one mammography center to another, or they get them done on a van, or old mammograms can’t be found for comparison. That doesn’t happen in the Dutch system.”
This study confirms guidelines already followed in the U.S. The American Cancer Society recommends that a woman start annual mammograms at age 40 and continue for as long as she is in good health.
The U.S. Preventive Services Task Force (USPSTF), part of the U.S. Department of Health and Human Services, recommends that women have mammograms every two years from age 50 to 74. These are similar to guidelines followed in the Dutch study.
The USPSTF does not recommend routine mammograms in women aged 40 to 49. It recommends that initiating mammogram screening before age 50 should be determined on an individual basis, taking into account patient values and risks vs. benefits.
“This study enforces previous information,” says Michael LeFevre, MD, who is co-vice chair of the U.S. Preventive Services Task Force. “It supports what we’ve already recommended. The Task Force certainly finds mammography to reduce mortality for breast cancer.”