The US Preventive Services Task Force (USPSTF) released new breast cancer screening guidelines in November of 2009 (and then updated language 12/09). These guidelines have caused quite a stir among health care providers, breast cancer advocacy groups, and the general public. 

They recommend that screening mammography be preformed every 2 years in women 50-74.

The decision to start regular biennial screening mammography before age 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.

There is insufficient evidence that there are additional benefits and harms of screening mammography in women 75 years or older.

They recommend against teaching self breast exam. There is adequate evidence that teaching women to do breast self exams does not reduce breast cancer mortality.

The current evidence is insufficient to assess the additional benefits and harms of clinical breast examination beyond screening mammography in women 40 years or older. In other words,  clinical breast exams may not offer additional benefit to women already receiving mammograms.

The current evidence is insufficient to assess the additional benefits and harms of either digital mammography or MRI instead of film mammography as screening modalities.

What does all this mean? First, let's decipher the language used by the USPSTF. It can be difficult to understand even if you are a health care provider. What does insufficient evidence mean? That means that there have not been enough high quality research studies to show that there is harm or benefit. They use this language in regard to both screening mammography and clinical breast exams (breast exam by a health care provider). In other words, they believe that there is not enough good research to show that women over the age of 75 should get mammograms or that clinical breast exams are useful in women after the age of 40. In addition, there is not enough research to show that digital mammography or MRI is better or worse than film mammography.

All the excitement is about the fact that they have changed their recommendation about when screening mammograms should be initiated and how often they should be performed- every two years in women 50-74. This is in conflict with the American Cancer Society recommendations which have not changed: 

Yearly mammograms starting at age 40 and continuing as long as a woman is in good health.

Clinical breast exam every 3 years age 20-40 and yearly after age 40.

Breast self exam is an option starting in the 20's.

High risk (>20% lifetime risk) women should get an MRI and mammogram yearly.

Why did the USPSTF make these changes? The new guidelines should not have been surprise to those in the breast cancer community. In 1997 the National Institutes of Health Consensus Development Conference came up with similar guidelines. They also faced similar public outcry therefore they amended their recommendation to include screening mammography every one to two years for women ages 40 to 50.

Let's take a look at some of the data. Among women in their 40s, one breast cancer death would be averted for every 1900 women screened regularly for 10 years. Among women in their 50s, one breast cancer death would be averted for every 1300 women screened. And among women in their 60s, one for every 377 screened. So, the older the woman is the more benefit she receives from screening mammograms.

Our understanding of the biology of breast cancer is changing. Another important fact to consider is that most women have slow-growing tumors so there is less benefit to screening women every year. Research shows that in the case of fast-growing aggressive tumors, annual mammograms are not of benefit because the cancer is usually detected after metastasis.  Screening mammograms are really only helpful for breast cancers that are slow-growing when early detection and treatment can change the course of the disease.

Mammography is still our best breast cancer screening test but it has many imperfections. There are an enormous number lesions found that do not turn out to be cancer, it misses one in five real cancers and there are many difficulties in interpreting mammographic findings. Most problematic is that mammography screening finds many slow-growing cancers that might never become life-threatening. These women will be treated with surgery, radiation and chemotherapy for something that never needed to be treated. One of the harms of screening is over diagnosis.

Further research is needed to identify the different subsets of breast cancer. Specific treatments will eventually be developed to address specific types of breast cancer. In addition, we need to better assess individual risk so that we can identify women who should be screened or offered chemoprevention with medications like tamoxifen or raloxifene.

What should you do? As the new guidelines suggest, decide what's best for you. Identify the risks and benefits of screening mammography within the context of your personal medical and family history. Discuss the pros and cons of screening with your health care provider and make a decision that is right for you. Don't forget to engage in behaviors that reduce your risk of getting breast cancer. Here is alink to the American Cancer Society site for more information abourt prevention.