The United States Preventive Services Task Force (USPSTF) has posted draft breast cancer screening recommendations for public comments (http://screeningforbreastcancer.org/) along with supporting information. The opportunity for public comment ends May 18th. The 2015 draft recommendations are similar to the 2009 recommendations:
- The USPSTF recommends biennial screening mammography for women ages 50 to 74 years. (“B” rating meaning that USPSTF recommends the service and there is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial).
- The decision to start screening mammography in women prior to age 50 years should be an individual one. Women who place a higher value on the potential benefit than the potential harms may choose to begin biennial screening between the ages of 40 and 49 years. (“C” rating meaning that USPSTF recommends selectively offering or providing this service to individual patients based on professional judgment and patient preferences. There is at least moderate certainty that the net benefit is small.)
There was insufficient evidence to make a recommendation for women age 75 and over because women in this age group were not included in randomized trials of breast cancer screening. Similarly the USPSTF found insufficient evidence on the benefits and harms of tomosythesis (3-D digital mammography) as a primary screening method as well as insufficient evidence on the use of additional imaging technologies for women with dense breasts after a negative mammogram.
Breast density based on the American College of Radiology’s Breast Imaging Reporting and Data System (BI-RADS) is a well-established risk factor for developing breast cancer; however it has not been shown to increase the risk of dying from breast cancer. Higher breast density reduces both the sensitivity and specificity of mammography, decreasing the likelihood of detecting a tumor with mammography and increasing chances of false positive results. Currently 22 states have breast cancer density reporting laws which requires facilities that perform mammograms to notify women if they have dense breasts. The USPSTF draft recommendation concludes that more evidence is needed to understand how the frequency of screening might affect important health outcomes in women with dense breasts.
As with the 2009 recommendations, the draft statement has generated considerable discussion, and much around the role of the USPSTF recommendation in relation to the Affordable Care Act which requires coverage of preventive services without cost-sharing (e.g., copayment or deductible) under new health insurance plans or policies, if they have a USPSTF grade of A or B. Currently the Affordable Care Act utilizes the 2002 recommendation on breast cancer screening of the U.S. Preventive Services Task Force rather than the 2009 recommendations to ensure access to mammography for women ages 40-49. Click here to view USPSTF A and B Recommendations.
Learn more about these Breast Cancer Screening Draft Recommendations
Kathy Cronin, Ph.D, Deputy Associate Director, Surveillance Research Program (NAACCR Committee Member)
After many years of study, mammography recommendations still remain controversial. In developing the recommendations, the USPSTF considered both the harms and the benefits of mammography and assessed the evidence to determine whether there would be a net benefit to women who are screened. The benefits are measured in the reduction of mortality from breast cancer and reduction in morbidity associated with earlier detection and hopefully less treatment. The harms are more difficult to measure and assess. The most serious harm is associated with the detection and treatment of tumors that may not ever have been detected without screening which leads to unnecessary treatment, often referred to as overdiagnosis. Based on our SEER data we see that women with very early disease receive surgery, many also receive adjuvant treatment, and over 30% of women with in situ disease receive mastectomies even though it is not clear what proportion of these women would have progressed to invasive disease. The most common harm is false positive screening tests which lead to additional mammograms and possibly biopsies. The uncertainty during the period of follow up causes anxiety and stress for women in addition to the added costs to women and to the health care system. Although much work has been done to quantify the degree of harms and benefits of breast cancer screening, for women between 40-49 years of age, the USPSTF draft recommendation states that the decision to be screened should be an individual one in consultation with their doctor.
The USPSTF reached out to the Cancer Intervention and Surveillance Modeling (CISNET) group for the 2009 and 2015 updates for mammography screening to help quantify the harms and benefits associated with different screening intervals and various ages to start and stop screening. Modeling uses information available through clinical trials and observational data to gain a better understanding of disease progression before diagnosis. Understanding the natural history of breast cancer provides the basis for predicting how screening could disrupt the natural progression through earlier detection and treatment. Incidence rates from cancer registries along with population screening utilization gives critical insight into the impact of screening. Modeling using this information attempts to parse out the portion of the increase in incidence that is explained by screening versus changes in risk as well as the portion of the decline in mortality that resulted from screening versus treatment advances.
Available information, including modeling that heavily relies on registry data, helps clarify the benefits and harms associated with different ages and screening schedules. For example the draft recommendation of “C “ for women ages 40-49 does not reflect a lack of evidence of benefit, but rather a tipping of the scale in the direction of harms because of a smaller number of deaths avoided with screening in this age group. Similarly, the added harms of screening every year versus every other year appear to outweigh the additional benefits. The fact that the most serious harm of overdiagnosed cases is not observable, since it is indistinguishable from a women who benefited from early diagnosis and treatment, makes decisions related to screening particularly complex. Registries are uniquely positioned to contribute to this area of research, particularly through the linkages of tumor specimens with longer term outcomes recorded in the registry system. Also, research is underway to identify markers that distinguish between aggressive and indolent disease at diagnosis, thereby avoiding overtreatment associated with early detection and maximizing the utility of cancer screening. However, until we have the capability to differentiate those tumors that will progress from those that do not, determining when and how often to screen will continue to rely heavily on a woman’s preferences and individual circumstances. The information provided in the USPSTF draft statement provides women with scientific data on the benefits and harm associated with breast cancer screening so that they can make informed decisions with their doctors.
The opinions expressed in this article are those of the authors and may not represent the official positions of NAACCR.