On May 18th, we submitted our official comments to the United State Preventive Services Task Force about their draft guidelines for mammography screening.
Dear U.S. Preventive Services Taskforce,
I am writing on behalf of Breast Cancer Action, a national education and advocacy organization working to end the breast cancer epidemic. We know that evidence-based information is of utmost importance to women living with and at risk of developing breast cancer, and we welcome the opportunity to provide feedback. I have submitted detailed comments to the online public comment form and am supplementing those comments with this letter.
Last year, Breast Cancer Action submitted comments to the USPSTF about the research plan to develop new mammography screening guidelines. We had a number of recommendations for the task force including; 1) the need for evidence-based recommendations for women of color and women of intermediate risk, 2) the need to dramatically reduce the harms of over-diagnosis and over-treatment and 3) the need for alternative non-invasive screening modalities that are better at finding aggressive cancers.
We believe that the current draft recommendations for mammography screening announced last month do not go far enough. The core of the recommendations fail to respond to the shift in data that calls into doubt the value of population-level mammography screening for all women, no matter their age. These current recommendations overstate the benefits of screening mammography for women of all ages and misrepresent the data for 50 year olds by grouping them with 60 year olds. In fact, in 2014, the largest mammography study to date, found that screening average-risk women – before they could feel a lump in their breasts – did not lead to lower breast-cancer death rates for those in their 40s and 50s. And the National Cancer Institute came to a similar conclusion in an analysis of multiple mammography studies involving nearly a half-million women: “Screening for breast cancer does not affect overall mortality.” This research adds to a large body of evidence that questions population based mammography screening even for women beyond their 40s.
We are also concerned that the information is not presented clearly. This lack of clarity can lead to misunderstandings of the recommendations and does not help women make an informed decision about mammography screening. First and foremost, it is imperative that the taskforce clarify the uses of mammography to distinguish between using mammography for general population-wide screening versus its uses as a surveillance and diagnostic tool.
Second, the harms and limitations of mammography screening should be clearly presented at the outset rather than embedded further into the document. As written, the harms and limitations of mammography screening are implied to apply only to women in their 40s rather than to all cohorts/age groups. In addition, the harms need to be expanded and either be (a) listed under each age bracket or (b) part of an overarching introduction to the issue. In order to clarify the harms and benefits, the inclusion of a chart with numbers or an infographic would help to quantify the harms/benefits of screening. This visual should include: how many women will get breast cancer, how many of these cancers will be caught by mammogram, how many women will die of breast cancer with/without screening, how many women will die of other causes (all-cause mortality not improved by screening), how many women will get false positive, number of women overtreated/overdiagnosed, etc.
In order for women to make clear choices they also need more complete information about risk. The draft recommendations as written imply that family history is the main risk factor and that this risk factor only applies to women in their 40s. While family history important, hereditary breast cancer accounts for less than 10% of all breast cancer cases therefore the recommendations can do a better job of providing more information about other risk factors. There are a number of other risk factors that are missing including emerging knowledge of the increased risk of breast cancer from chemical exposures (such as benzene and endocrine disruptors), the known risk of Diethylstilbestrol (DES) exposure, and occupational toxic exposures for women in certain occupations such as nail salon workers, fire fighters and workers in the automotive plastics industry. It is important to include this emerging body of knowledge as it may be important risk factors for many categories of women.
Based on the plan put forth last year as well as our submitted comments, we were also disappointed to see that some information was missing from this current version of draft recommendations. We expected to see better information on risk assessment for different categories of risk. For example, although the draft recommendations defines both women who are average risk and high risk, this leaves a missing definition of what intermediate risk is and how mammography recommendations may differ for this group of women. Lastly, it is important to include the evidence for multiple breast cancer screening modalities in addition to mammography, in order to prevent any assumptions that other methods may be better. This includes a complete assessment of other modalities including ultrasound, MRIs or thermography, which are currently missing from the draft recommendations.
Finally, as an independent expert panel charged with providing evidence-based recommendations, it is not clear what evidence is being used to substantiate some of the recommendations. For instance, the panel states that women in their 60s derive the greatest benefit from screening mammography in terms of preventing breast cancer death, but it does not substantiate the continued recommendation for biannual screening of women in their 50s. The evidence it does use seems to imply that there is no good evidence for the biannual screening interval for women 50-74. The recommendations clearly states that “there are no clinical trials that compare annual mammography with a longer interval in women of any age” and observational evidence “found no difference in breast cancer deaths between women age 50 years and older screened biennially versus annually.” In fact, in light of the evidence, it is not clear that screening is having the desired effect of extending women’s lives.
In summary, the USPSTF Recommendation Statement could be more useful to women if the following additions and changes were made for the final recommendations:
- Complete and transparent risk assessment information. This would include a through description on who these recommendations apply to, who is not included and why. Also, information on emerging knowledge of risk factors such as chemical exposures (such as benzene and endocrine disruptors), the known risk of Diethylstilbestrol (DES) exposure, and occupational toxic exposures.
- Provide quantified data to support informed decision making. In suggesting women make their own decision about screening, the USPSTF should provide clearer explanation of harms and benefits for all women, not just women in their 40’s. We would like to see a chart/infographic that clearly shows the need to treat to get benefit for mammography screening. Also, under the different protocols for the different age groups, how many women will get breast cancer, how many women will be diagnosed with breast cancer from a mammogram (vs found in other ways), how many women will die (and does this number change with a mammogram), etc.
- Substantiate recommendations for biannual screening of women in their 50s by connecting the evidence to the recommendations. These current recommendations overstate the benefits of screening mammography and fail to respond to the shift in data that calls into doubt the value of population-level mammography screening for women of all ages.
Thank you for the opportunity to submit our comments on the U.S. Preventative Services Task Force (USPSTF) Breast Cancer Screening Draft Recommendations.
Program Manager, Breast Cancer Action