Breast cancer is the most common form of cancer in women and the second leading cause of cancer deaths in American women.  In 2009, approximately 194,280 patients were estimated to be diagnosed with invasive breast cancer, and 62,280 with carcinoma in situ.  An estimated 40,610 would have died of this disease.  For a woman of average risk, the lifetime incidence of breast cancer is one in eight.

In November 2009, the U.S. Preventive Services Task Force (USPSTF) published its recommendations: 1) against routine screening mammography in women aged 40 to 49 years, and 2) for every other year screening mammography for women between the ages of 50 and 74 years.   The USPSTF states that the current evidence is insufficient to assess the benefits of mammography in women 75 years or older.

These new recommendations sent shockwaves throughout the country.  All major cancer organizations including the American Cancer Society voiced their disagreements with these new government guidelines.  It is a well known fact that screening of asymptomatic women has been accredited for the decline in mortality of breast cancer.  This is particularly true for “young” women, the group less than 50 years old.  Even the USPSTF agrees that among women between 39 and 49 years of age, screening mammography results in a 15% reduction in the risk of death from breast cancer. 

However, 1,904 such women need to have mammograms to prevent one single death.  For women aged 50 to 59 years, the number needed is 1,339; and the risk reduction is 14%.  One possible interpretation is that it is acceptable to waste 1,338 screenings (1,339 – 1) but unacceptable to waste 1,903 (1,904 - 1).  If you are between 39 and 49 years of age, is your life worth making 1,903 other women have mammograms?  Conversely, would you be willing to get a mammogram so that one life out of 1,904 be saved?

The harms of mammogram stem from false-positives, meaning an abnormality on mammogram that turns out to not be cancer.  The USPSTF lists pain, anxiety, return doctor visit, and unwarranted imaging and biopsy.  Furthermore, overdiagnosis can happen, meaning that detecting and treating that breast cancer would not make a difference in the woman’s lifespan. 

According to the USPSTF report, “because the likelihood that DCIS (ductal carcinoma in situ, a form of early breast cancer) will progress to invasive cancer is unknown, surgical removal – with or without adjuvant treatment – may represent overdiagnosis or overtreatment.  We know that in situ cancer can become invasive cancer that is potentially lethal; we just don’t know when and in whom.  So if it’s you, would you like to leave the DCIS in your breast and watch it grow?

Thanks to the outcry from doctors and patients alike, the USPSTF statement is not being used to deny insurance coverage for mammogram in women aged 40 to 49 years.  The current recommendation still stands, and it is annual screening mammogram starting at age 40.  The age at which screening is stopped should be individualized by considering the potential risks and benefits of screening in the context of the woman’s overall health status and longevity.