By Pramern Sriratana, MD, Mid-Illinois Hematology & Oncology Associates
Mammography has been the mainstay of breast cancer screening for many years. Most women over 40 have had at least one mammogram and are aware that mammography screening is believed to be the best tool currently available for a breast cancer diagnosis. In the last few years, supposed new findings have led to changes in screening mammogram recommendations. The U. S. Preventative Services Task Force (USPSTF) changed its recommendation in 2009 from starting annual screening mammograms at age 40 to biennial screening mammograms at age 50. The American Cancer Society has maintained its recommendation for yearly mammograms starting at age 40 and continuing for as long as a woman is in good health, along with clinical breast exams (CBE) about every three years for women in their 20s and 30s and every year for women 40 and over.
Reasons behind the USPSTF recommendation change include concerns about overdiagnosis of breast cancer and concerns about false positives. However, the USPSTF recommendation change resulted in confusion and concern among women and their physicians. Now, women don’t know what to think. Should they wait until 50 for a screening baseline mammogram or start mammograms at 40? Do they need annual or bi-annual mammograms? Additional information and analysis regarding these recommendations is needed in order to provide some clarification to women and their physicians.
Many feel that the data on which the USPSTF recommendations were based are controversial. Others have reviewed the studies on which these recommendations were based and have found questionable study methods and flawed analysis. While the authors of the studies stand by their findings, it is clear that there is not universal agreement in the study methods, analysis, or findings.
The two main issues on which the USPSTF based their recommendations were overdiagnosis and false positives. Many women do not truly understand what these terms mean or how they were defined in these studies. According to the study authors, overdiagnosis refers to the detection of cancers on screening mammograms that would never become clinically evident. Those in favor of reduced mammography screening state that these “overdiagnosed” cancers result in women undergoing treatment for cancers that would never have caused problems. Some claim that these cancers would disappear on their own if left undiscovered. Those that question this term point to the fact that no reports have ever been made of breast cancers disappearing on their own without some type of treatment. In addition, measuring how many cancers are “overdiagnosed” is quite difficult. Thus, the critics say, claims of overdiagnosis are scientifically flawed.
The second important issue is that of false positives. This refers to findings on screening mammograms that result in women being called back for additional tests, either additional mammograms or ultrasounds. These false positive results do not result in a cancer diagnosis. Approximately 10 percent of women are recalled for these additional evaluations. This is very similar to the recall rate for women with questionable Pap smears. The majority (56 percent) of these recalls involve only further mammograms or ultrasounds. While these “false positives” can result in anxiety and inconvenience for these women, critics do not feel that anxiety and inconvenience outweigh the assurance associated with following up on a questionable mammogram.
So what should women do? There are some tools available to help them decide. One of these is the Gail model or Breast Cancer Risk Assessment tool (www.cancer.gov/bcrisktool). While not perfect, this tool can calculate a woman’s risk of developing breast cancer. Discussions between women and their health care providers can reveal other risk factors as well. Women at higher risk might want to be more aggressive with mammography screening. Women should also have a discussion with their primary care physician about the risks and benefits of mammography screening. This discussion should include the individual woman’s values and preferences as well as provide accurate and balanced information. Age, risk, and other factors will come into play in each woman’s individual decision. Women should work with their physicians to make the decisions they feel are the best for them, and are the most comfortable with.
While the changes in recommendations and information in professional and popular media can cause confusion and uncertainty among women and their health care providers, communication is key for making informed decisions. A discussion of risk factors, perhaps including the Breast Cancer Risk Assessment tool, can help women evaluate their risk as well as the risks and benefits of mammography screening. Open communication and information can help women make the best decisions about their health care.
For more information, contact Mid-Illinois Hematology & Oncology Associates, Ltd. at 309-452-9701 or online at www.mihoaonline.org.
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