When to get screened for breast cancer with a mammogram has been under debate for years, with some professional organizations recommending the early and often approach and others questioning the usefulness of mammograms all together. Now the American Cancer Society (ACS) has weighed in with new guidelines about when to get screened. The recommendations could affect the way women across the United States get screened.
The Importance of Screening Tests
Breast cancer is a great example of an illness that’s often easier to treat or prevent in the early stages. Many breast cancers can be removed or treated more effectively in the early stages of disease. Once they become obvious and cause a lot of symptoms, they’re often harder to remove and treat. As a result, doctors have come up with several screening tests for breast cancer, including mammograms and manual exams, to try and catch them before they become extensive and untreatable.
The problem with any test, including the mammogram, is that it’s rarely 100% accurate. Some people will have tests showing they have breast cancer when they actually don’t (called a false positive) and others will have tests showing they don’t have breast cancer when they actually do (called a false negative). How likely you are to believe a positive or negative result depends mostly on three things:
- The statistics behind the test itself. Some tests just aren’t as accurate as others and may identify those with disease 50 percent of the time while others are close to 100 percent. Research has shown that over the course of 10 years, 50% of women will receive a positive mammogram test result that should have actually been negative (false positive test). On top of that, it’s possible that some women may have breast cancer, even if their tests are negative (false negative). If you want to know how accurate the test is, you can ask your doctor about the test’s sensitivity and specificity.
- How likely the person is to have the disease. If a person is at high risk – a 52-year-old woman who’s BRCA positive, for example – you’re more likely to trust a positive result over a negative one because the woman is much more likely to have breast cancer. On the flip side, you’re more likely to trust a negative result in someone who isn’t very likely to have breast cancer, like in a 40-year-old woman with no risk factors.
- How many people you want to workup afterward. Reading a mammogram or feeling a breast lump can be very subjective. With any screening test, you need to figure out how aggressive you want to be when picking positive tests. You can think again of the screening as a net. If the holes in your net are small, you’ll end up catching most people, even if only some of them really have the disease. If you make the holes in your screen too big, you’ll only catch the most likely to have disease, but you might be missing a bunch of people with the disease as well. In this case, the hole size of the breast cancer net is determined by how often and how early you start screening with mammograms.
Whether or not a mammogram or breast exam says you have cancer isn’t absolute. Instead, it’s a careful balance of the factors mentioned above. If every woman of every age were screened regardless of their risk with a test that wasn’t very specific, the result would be a lot of false positives.
The Risks of Testing
The problem with the workup after a positive exam is that it carries numerous risks and possible harms. A positive mammogram test causes many women to worry unnecessarily that they have breast cancer. While this might not seem like a big deal, weeks or months can pass between different parts of the workup and women may live in limbo worrying they might have cancer for long periods of time. Some choose not to get further tests for fear of false positives in the future. The tests done to verify mammograms or manual breast exams can also lead to complications. Biopsies of breast masses can lead to deformity, pain, and infection that can lead to loss of the breast in rare cases. In some situations, women may undergo cancer treatment for cancers that are slow growing and would never have posed any real threat to their life. Treatments like chemotherapy, radiation, and surgery can all have long-lasting and sometimes serious health consequences. Deciding to get a screening exam means the risks of not screening outweigh the benefits.
These factors caused the ACS to look at the groups at highest risk, the risks and benefits involved in treatment, and new studies about how many false positives and false negatives occur when using manual breast exams or mammograms. Since many new studies had come out since the last recommendations were made in 2003, they thought it was important to revise their earlier position to make it more in line with new research with the goal of making sure only the women who needed screening were getting it.
The New Breast Cancer Screening Guidelines
The guidelines are as follows:
- Women with an average risk of breast cancer – most women – should begin yearly mammograms at age 45.
- Women should be able to start the screening as early as age 40, if they want to. It’s a good idea to start talking to your health care provider at age 40 about when you should begin screening.
- At age 55, women should have mammograms every other year – though women who want to keep having yearly mammograms should be able to do so.
- Regular mammograms should continue for as long as a woman is in good health.
- Breast exams, either from a medical provider or self-exams, are no longer recommended.
If you’re between 40 and 45, it’s your decision to start mammograms, but it’s not clear that the risks will outweigh the benefits and you should have a conversation with your doctor about whether you really need to start so early. In addition, yearly screenings may not be necessary. Getting screened yearly increases the likelihood of a false positive result, but may also pick up a cancer earlier. Women over 55 may benefit from moving to an every other year schedule to minimize their chances of a false positive. Finally, these guidelines recommend never doing manual breast exams, either at home or in the clinic. This is because these exams aren’t specific or accurate enough to tell what’s cancer and what’s not. They lead to many false positives and women getting procedures they really won’t benefit from.
For more information, visit the American Cancer Society.