What guidelines are we talking about?

The American Cancer Society has issued new recommendations on when women should get mammograms and how frequently they should get them. It isn't the only group that issues guidelines on this screening test but it is considered among the most influential.

In a paper published in JAMA on Tuesday, the ACS made the following updates to its guidelines:

  • Increased the minimum age at which a woman of average risk should start getting routine mammograms to 45 (it was previously 40).
  • Changed the frequency of when mammograms should be given. Women ages 45-54 should get mammograms annually and those 55 and older should get them every other year.
  • Recommended that doctors stop screening women with a life expectancy of less than 10 years.
  • Recommended against routine clinical breast examination.

The ACS emphasized in its recommendations that women should still have the opportunity to be screened earlier or more frequently if they choose -- wording that appears to be designed to make sure insurance companies continue to pay or these screening and doctors give women the option to do so.

Note that the changes apply to women with average risk only. Those who have a higher risk should still get more intensive screening.

Why did they make these changes?

There's some research that shows a woman's risk of getting breast cancer and dying from it goes up at around age 45. While the risk still exists at 40, it's somewhat lower but the risks from false positives are somewhat greater. After menopause, a woman's risk of breast cancer does actually increase but the cancers tend to develop more slowly.

The decision about stopping screening for women with a shorter life expectancy is a recognition of the unnecessary emotional and physical toll interventions may have on someone who may be more likely to die with a breast cancer tumor than from it.

The recommendation against manual breast exams doesn't mean that doctors shouldn't do them if they want to -- just that they shouldn't feel obligated to do so. This decision was made because the ACS guidelines panel felt the evidence showing it is helpful at catching cancers that mammograms don't pick up is not very strong and that physicians could better use the time (the exams take three minutes per breast or six minutes total if done right) during a typical 15 to 30 minute appointment.

What do other organizations recommend in terms of the age when screening should begin and the frequency of screening?

U.S. Preventive Services Task Force: 50, every two years.

American Cancer Society: 45, yearly until age 55 and then every other year.

American Congress of Obstetricians and Gynecologists : 40, yearly

Yes, you read right. These three groups recommend three different ages for starting regular mammograms.

The American Cancer Society updated the guidelines for breast cancer screening. (Victoria M. Walker/The Washington Post)

How do I know if I'm at average risk or not?

There isn't a consensus about what this means, but there are a few different methods of calculating your risk in the medical literature. If you have a gene variant like BRCA1 or BRCA2, a family history of breast cancer, or have had cancer in other parts of your body, you are likely at higher than average risk. This is something to discuss with your physician, but it's important to know that some critics of the ACS guidelines say the fact that average risk is so poorly and inconsistently defined is one of the reasons why they still recommend being cautious and continuing to screen starting at age 40.

Why is there so much disagreement about mammograms?

This is worth repeating in case the message has been lost in all the talk about the controversy regarding mammograms: Medical experts agree that mammograms save lives and that they are the best thing a woman can do to reduce her risk of dying from breast cancer.

What they disagree on is how many lives are being saved (whether it's a huge number of lives or a really huge number of lives), the extent of the problems with over diagnosis and false positives and what this means about when the benefits outweigh the risks.

Wait -- what harms? I thought mammograms were just X-rays and non-invasive.

They are. Part of the issue is emotional. The science of mammograms isn't exact and a significant number of women are recalled to take another mammogram after the first, causing a lot of anxiety. Sometimes those second mammograms are inconclusive or show something that might be a tumor and the doctor orders a biopsy to make sure.

Biopsies, which involve harvesting a bit of tissue from the breast to see whether it's cancerous are, of course, invasive and some in the medical community think we're doing too many of these that end up turning up nothing. In addition, there's been a lot of controversy over what are known as stage 0 cancers, or ductal carcinoma in situ, which involves the presence of abnormal cells in the milk ducts. In many of these cases, the abnormal cells never develop into full-blown cancer that threatens the life of the woman. But some women who receive this diagnosis are choosing to be very aggressive in their treatment and may get both breasts removed. While it is a woman's right to choose to do this, many doctors are concerned that this is a result of too much fear about breast cancer and a lack of understanding about this early stage condition.

I think I understand the basic debate now, but I still don't know what to do. Which group should I listen to? Whose advice is the 'best'?

That's the question of the moment.

The medical groups that put out recommendations on mammograms recognize that the conflicting guidelines will be confusing to women. The American Congress of Obstetricians and Gynecologists said Tuesday that it would convene a meeting in January with the other groups to try to come up with a set of "consensus" guidelines. Until there's more information, the best thing you can do is to learn more about the potential benefits, limitations and harms associated with breast cancer screening and to make sure to talk to your doctors about what makes sense for you. Breast cancer patient groups say that you should update your physicians at each appointment with information about diagnoses in your family and other relevant information even if they don't ask.

The full text of the American Cancer Society announcement in JAMA can be found here. And an editorial explaining the significance of the changes here.

U.S. Preventive Services Task Force draft guidelines for mammograms here.

American Congress of Obstetricians and Gynecologists guidelines for mammograms here.

Read more:

For more health news, you can sign up for our weekly newsletter here.