New Study Questions Effectiveness Of Mammograms
The effectiveness of mammograms for women over 50 is being called into question by researchers at the Harvard School of Public Health (HSPH) and the Cancer Registry of Norway.
The researchers, who published their findings in Thursday’s edition of the New England Journal of Medicine, compared mortality rates of more than 40,000 breast cancer victims between the ages of 50 and 69. They discovered that the preventative screening wasn’t nearly as effective as some health organizations have claimed.
"The observed reduction in death from breast cancer after introduction of the mammography screening program was far less than we expected," lead author Mette Kalager, a visiting scientist at HSPH and a surgeon at Oslo University Hospital in Norway, said in a statement. "The results showed that other factors”¦ actually had a greater effect on reducing mortality from breast cancer."
Four different groups of subjects were studied. One group lived in Norway between 1996 and 2005 and received a mammogram screening, while a second lived in counties that did not have access to the screenings during the same time period. The third and fourth groups were similar to the first two, but their results came from 1986 through 1995 and were used as historical reference.
"Among women in the nonscreening group, there was an 18 percent reduction in the rate of death from breast cancer, as compared with the preceding 10-year period, presumably as a result of increased breast-cancer awareness, improved therapy, and the use of more sensitive diagnostic tools," the study found, according to a CNN.com report.
"Among women in the screening group, there was a 28 percent reduction in mortality from breast cancer during the same period. Thus, the relative reduction in mortality that was causally related to the screening program alone was 10 percent," Kalager and colleagues Marvin Zelen, Frøydis Langmark, and Hans-Olov Adami added.
However, only a third of the reductions–or 2.4 of the 7.2 deaths per 100,000 person years, to be specific–were due to the mammography screening itself, they claim. The remaining two-thirds, Kalager claims, can be attributed to "enhanced breast cancer awareness, improved diagnostic and treatment for breast cancer."
In comparison, in 2002, the World Health Organization (WHO) claimed that mammograms can lower the breast cancer death rate 25 percent in women between the ages of 50 and 69.
Getting a mammography is "not the great lifesaver that people think it is," Dr. Jeanne Mandelblatt, a Georgetown University researcher who helped revise U.S. mammogram guidelines last year, told Associated Press (AP) reporter Alicia Chang. "It’s not a magic bullet."
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