Mammograms not effective as thought - new study
A recent Norwegian study has found that breast cancer screening, commonly known as mammogram screening, may reduce the risk of death from breast cancer by only 10 percent.
Mammogram screening is indicated to diagnose breast cancer in its early stages; early diagnosis leads to early treatment, which many doctors believe is essential in reducing death risk.
For above mentioned study, Mette Kalager, M.D. and colleagues followed 40,075 women, screened and unscreened from 1996 through 2005. In the screening group, women were offered screening mammography every 2 years.
Among those who were screened, the rate of death was reduced by 7.2 deaths per 100,000 person-years as compared with the historical screening group, which showed a 28 percent reduction.
By contrast, the rate of death was reduced by 4.8 deaths per 100,000 person-years in the nonscreening group, compared to the historical nonscreening group, which is an 18 percent of reduction.
The risk reduction attributed to the mammogram screening is merely 10 percent, or 2.4 deaths per 100,000 person-years.
The findings were reported on Sept 23 in the New England Journal of Medicine.
Mammogram screening is an issue subject to an ever-lasting debate. This is not the only study suggesting that the life-saving effect of this screening method is quite limited.
Some studies have revealed that the benefit from mammogram screening could largely depend on who conducted the study. Jørgensen KJ and colleagues from the University of Copenhagen in Denmark conducted a study suggesting that the benefit may be zero.
The researchers found women ages 44 to 74 who had received mammogram screening had their risk of death from the disease reduced by 1 percent, compared to 2 percent reduction in the women who were unscreened. Similarly, no benefit was found in women aged 35 to 55 and those aged 75 to 84.
The findings were reported in the March 23, 2010 issue of British Medical Journal.
Brodersen J also published a study in March 2010 suggesting that women should be advised on benefits and risks of the breast cancer screening in absolute numbers so they can make an informed decision.
They said the screening may protect some women from dying from breast cancer, but many more women will be over-diagnosed, receive unnecessary treatment and false positive diagnosis and suffer both physical and mental stress.
Brodersen, et al said that to prolong one woman's life, 2000 women need to be screened for 10 years among whom, 10 healthy women will be over-diagnosed with breast cancer and receive needless treatment and more than 200 women will suffer substantial psychosocial distress for months because of false positive diagnosis.
The U.S. Preventative Services Task Force Agency for Healthcare Research and Quality recommended last November that mammogram screening every other year from ages 50 to 69 reduces breast cancer death by 16.5 percent over a life time compared to no screening whatsoever. This is compared to 19.5 percent for women who start screening at 40.
The USPSTFA recommends that women should start mammogram screening at 50 instead of 40 because earlier screening result in more physical and mental harm associated with further diagnosis and unnecessary treatment.
Breast cancer in many cases can be preventable, according to Dr. Colin T Campbell, a distinguished nutrition professor at Cornell University. A healthy lifestyle is believed to be important in preventing this disease, which is diagnosed in more than 175,000 women and kills about 50,000 in the United States each year.
By Jimmy Downs and editing by Rachel Stockton
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