Study confirms mammography reduces risk of breast cancer death
June 28th, 2011
12:07 PM ET

Study confirms mammography reduces risk of breast cancer death

A new study of more than 133,000 women confirms that regular mammography screenings reduce a woman's risk of dying from breast cancer.

The Swedish Two-County Trial study began in the late 1970s. In its first phase, researchers divided the study participants in to two groups: Women who were given regular mammograms, and women who were treated with "usual care," or treatment that did not include mammograms. That screening period lasted for seven years, after which the study's second phase began and the women were followed for an additional 29 years.

"We estimated about 1,300 mammograms need to be done to save one life," explains Robert A. Smith, Ph.D., director of Cancer Screening at the American Cancer Society and one of the study's authors.

To put that number another way, Smith and his fellow authors estimate that screening 300 women every two to three years for 10 years total prevents one death from breast cancer. Among the study participants, Smith calculates that 42 years of life were saved for every 1,000 women who were invited to have a regular mammogram during the study's screening period.

Yet despite studies like Smith's, who should get a mammogram and how often can be confusing questions. The American Cancer Society advises women to begin annual mammogram screenings at age 40.

"Women should think of mammography as a kind of insurance against getting a diagnosis with a breast cancer that will be harder to treat and may actually become uncurable," says Smith.

"It's not a perfect examination by any means but we have quite an accumulation of data that shows mammography is associated with a reduced risk of dying from breast cancer and the opportunity to be treated less aggressively."

But the United States Preventive Services Task Force says the decision to get a mammogram at the age of 40 is an individual choice that women should make with their doctors. Otherwise, the Task Force recommends women wait to begin regular mammography screening at the age of 50 and even then advises that mammograms are only needed once every two years.

In a statement to CNN, Dr. Virginia A. Moyer, chair of the task force, said these latest findings would probably  not change the panel's guidance.

"Overall, this study adds depth to our knowledge of the potential adverse effects of radiation exposure for mammography, but is not different from the estimates used in the 2009 recommendation, so would not be expected to significantly impact the debate."

The study is published online in the journal Radiology.

soundoff (12 Responses)
  1. Teresa

    Don't wait until you are 50! Mom had breast cancer at 42(lived) , my husband's grandmother at 46 (died). Cousin in mid 40's(lived). A personal choice to wait until 50 could be your death

    June 29, 2011 at 11:00 | Report abuse | Reply
    • Robin

      The truth is that your mother, your husband's grandmother and your cousin would almost certainly have had the same outcomes whether they had mammograms or not. Some cancers are deadly; many others so slow growing that a woman will die of old age before she even became symptomatic.

      Routine mammograms actually save very few lives. The findings in this study contrast greatly with more recent ones which consistently found 2000 women would have to be screened for 10 years before s single life is saved. And while that one life is saved, many more are damaged – and no doubt some lost – as a result of unnecessary treatment. Surgery, chemo, and radiation especially are not things to be trifled with. Research mammography and over-diagnosis. It's a serious problem, one your malpractice avoidant physician will likely never tell you about.

      Women are far more likely to die from heart disease and strokes than they are from breast cancer. Yet scant attention is paid to the special needs of women when it comes to the treatment of cardiovascular disease. The medical community and the media should spend some time addressing this fact and a little less obsessing about a single disease that is, in the scheme of things, far less of a danger.

      June 29, 2011 at 13:36 | Report abuse |
    • D

      @Robin-I am not sure I believe heart disease is more prevalent for women in their 40s than breast cancer.

      June 29, 2011 at 13:58 | Report abuse |
    • Robin

      D – Please re-read my post as I was not addressing the age issue. However, the 5 year risk of being diagnosed with breast cancer for the typical women at age 45 is less than 1%. Pre-menopausal women are at low risk. (and due to breast density, this is when mammograms are the most useless. But that's a separate story.) Now here are some facts about women and heart disease:

      1 in 4 women in the United States die from heart disease, while 1 in 30 die from breast cancer.
      23% of women will die within 1-year of having a heart attack.
      Within 6 years of having a heart attack, about 46% of women become disabled with heart failure.
      2/3 of women who have a heart attack fail to make a full recovery.

      June 29, 2011 at 14:29 | Report abuse |
  2. A scientist

    Although this is a valuable study, it does little to address the biggest controversy surrounding mammograms - at what age to recommend starting regular mammograms. The study participants ranged from 40-74 years of age. While there was an overall beneficial effect of mammograms, no analysis was done to see whether this benefit varied by age. It is likely that most of the beneficial effects of mammograms were on the older participants, since breast cancer becomes more common with age.

    It is worth noting that the article state, "Most of the prevented breast cancer deaths were those that would have occurred more than 10 years after inception of screening." In other words, since all of the participants were at least 40 when they started screening (and many were much older), very few of the lives saved would have been for people in their 40s.

    And I realize that the obvious rebuttal is that any life saved makes early screening worth it. The problem is that mammograms involve radiation (and false positives lead to invasive follow-ups, which carry small risks of complications), so the question is whether more lives are saved by early mammograms or lost due to the damage caused by the mammogram's radiation and by complications from follow-up tests. Unfortunately, while this study address this question for older women, it does not fully answer whether early mammograms cause more harm or good.

    June 29, 2011 at 12:12 | Report abuse | Reply
    • D

      I am not thrilled with the radiation exposure, either. In fact, some women genetically predisposed to cancer are actually MORE sensitive to radiation. So they are between a rock and a hard place. The only solution I see is development of better diagnostic technology for younger women and others with dense breasts. Women seem to be getting breast cancer earlier and earlier.

      June 29, 2011 at 14:02 | Report abuse |
  3. Pat

    This article left a detail that appeared in reports elsewhere– the women in the study aged 40-49 were receiving a mammogram every two years, and those betwen 50-74 were receiving one every three years. It would be easy to misinterpret "regular" as "annual" mamnograms, particularly in light of recent controversy in the US.

    June 29, 2011 at 12:26 | Report abuse | Reply
  4. D

    I don't understand why the only metric used is lives saved. It is quite possible that mammograms can catch disease earlier and help prevent chemo, radiation, and mastectomies. For my sister, she started getting mammograms in her late 30s, and had two separate mastectomies done after DCIS was found twice. She was spared the chemo and radiation that can be necessary when the cancer is more advanced. Even though mammography is an insensitive technique for younger women, there is benefit beyond lives saved.

    June 29, 2011 at 13:56 | Report abuse | Reply
    • Robin

      She lost her breasts, so I'm not sure how one can say she was spared anything. DCIS is a non-invasive breast cancer, and some experts argue it's not cancer at all and should not be so radically treated. It's always considered to be Stage Zero.

      And this is my entire point.

      June 29, 2011 at 14:38 | Report abuse |
  5. Kate

    I wish these stories mentioned informed consent. Women can make their own choices, and not doctors. Men get the courtesy of being treated like adults with prostate screening and I wish some was were give ALL the info as well.

    June 29, 2011 at 18:55 | Report abuse | Reply
  6. Hospitals

    Patients with CRKP tend to be elderly, have multiple health problems, and have a catheter or are on a respirator– foreign objects that can become breeding grounds for bacteria.

    June 30, 2011 at 04:29 | Report abuse | Reply
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