The Future of Breast Cancer Screening in the US
As a topic in women’s health, breast cancer is an outstanding issue. Estimates for 2012 by Komen for the Cure predict nearly 300,000 cases and 40,000 mortalities from breast cancer alone. Risk factors are varied according to the National Cancer Institute: family history, genetic mutation (on the BRCA 1 or 2 gene or the HER2 gene), personal histology of the breast, age (menopausal), bone density, and hormone regulatory factors (estrogen regulators in particular) all are correlated with an increased incidence rate of breast cancer. The National Cancer Institute explains that genetic mutations and their mechanisms are fairly well understood, yet breast cancer many times emerges as a surprise. Treatment comes in many shapes and sizes, from minimally invasive biopsies and chemotherapy to thermotherapy and radiation therapy; however, a solution is not guaranteed after the tumor has metastasized, according to the National Cancer Institute. Therefore, for effective therapy, early detection is critical.
Screening for breast cancer comes in many forms. Mammography, the most common technique according to the National Center for Biotechnology Information, analyzes tissue by taking X-rays directly through the skin: each breast is scanned independently and from multiple angles. With emerging digital technology, computer software can give better depth of view and three-dimensional representations of the sections being analyzed: composing multiple angles is known as tomosynthesis, and although this computer-aided detection is a powerful analytical tool, breast density remains a severe impediment for detection of small cancers, according to the National Center for Biotechnology Information. In fact, according to Stodjadinovic and colleagues in the Journal of Cancer, there is a 10-15% lower sensitivity for mammograms on post-menaposaul women for this very reason. Ultimately, computer-aided detection is only as accurate as the quality of the image taken. The problem of small, developing cancers is also not addressed by the other prevalent screening technique according to Stodjadinovic, namely clinical breast examination (CBE) and self breast examination (SBE). Although these techniques are cost effective and performed at little inconvenience, they are not medically effective, and in fact, SBE can lead to a sense of false security, according to Stodjadinovic and colleages. The problem with these physical examinations is that they are only effective at identifying large tumors that have been growing for years and therefore the false negative rate for tumors that are small or already metastasized is cripplingly high, the researchers explain.
So what options are left to detect small cancers? According to Kelly and colleagues, both higher intensity imaging and localized molecular assays may be viable possibilities. Higher intensity images can come in the form of breast MRI, cone breast MT scans, and possibly PET scans for higher specificity of metabolites, the researchers explain. According to radiologyinfo.org, breast MRI involves image formation by applying a strong magnetic field coupled with radiofrequency pulses that interact with a contrast dye to form an image. Kelly and colleagues posit that MRIs are advantageous because they allow deep tissue penetration. Although ionizing radiation is in low doses, MRIs are usually only performed if a patient is at a high risk level, the authors explain. There is also risk of heavy metal poisoning from the galodinium dye used if a patient undergoes repeated scans. On the other hand, cone breast MT scans are also an improvement on mammography because they allow for capture in the 3-D field directly; however, concentrated radiation is once again an issue, according to the authors. Finally, PET scans, which are able to screen for specific macromolecules that may be involved with a carcinogenic mechanism, are extremely specific but require exposure equivalent to 20 MRIs, the authors explain. The common thread is clear: more detailed imaging runs the risk of dangerous levels of radiation, which may itself induce malignancies for which it is trying to screen.
Economic costs of MRIs, CTs, and mammographies are anything but low. Hospitals easily bill several thousand dollars per scan. Fortunately, ultrasound and immunological assays present options that can cover both medical and economic fronts for breast cancer screening. Kelly and colleagues argue that automated ultrasound recording and portable ultrasound devices have been designed to find small tumors on the scale of 5 mm (however still not as precise as MRI scans).They find that portable ultrasound devices are substantially cheaper and more scalable than MRI machines, and they can be used by trained professionals instead of radiologists. The learning curve for ultrasound screening is low, making the availability of quick, routine, and relatively precise scans more accessible, the authors explain, and these devices have been used for the purposes of telemedicine – patients themselves can scan after application of an agar gel and transmit images remotely. Finally, Kelly and colleagues suggest ultrasound also sidesteps the safety hazards associated with low dose ionizing radiation completely by using sound waves instead of electromagnetic pulses. Besides refined imaging alternatives, Stojadinovic and colleagues suggest that molecular assays also show promise in screening. The CTC/DTC assay takes a sample of blood to search for proliferating tumor cells before tumor formation or metastasis, and other novel biomarkers are looking to identify metabolites present in breast cancer pathways, the authors explain. These mechanisms are highly specific; therefore, accumulation of the appropriate set of markers is a very precise indication that cancer has the potential to form in a given area from which the sample was collected, according to the authors. One can also screen for genetic mutations in a predictive manner, although that knowledge in some cases may be inaccurate or instill undue fear, the authors explain. Regardless, what is most important for these assays is that cost or safety are negligible factors compared to the aforementioned alternatives.
Ultimately, accuracy and cost-effectiveness in screening procedures are necessary but not sufficient. False negative and false positive reporting leads to unnecessary follow-up and resource use. But these errors are more prone to occur in high-risk groups. Therefore, it is important to address what the screening audience should be and where accessibility needs to be improved in order to make early detection prevalent. Evidence based medicine will be critical; currently, the CDC reports that the screening rate is significantly lower in Asian American women than in black or white women. Moreover, mammography rates are beneath the target goal set by the Healthy People 2020 committee, especially for the uninsured and underinsured population, according to the CDC.
Technology can only go so far before it needs funding and a culture for widespread implementation to take place. The PPACA or health reform bill of 2010 takes steps to expand in both these directions. Now there is a ban on medical rescission so insurance companies cannot reject patients with cancer.The Commonwealth Fund reports that some 20,000 patients between 2003 and 2007 with breast cancer fell into this category. For Medicare patients and private insurance companies that haven’t been grandfathered in, breast cancer screening will be provided biannually, free of cost. Enhanced Federal Medical Assistance Percentage (FMAP) will be provided for states that fund breast cancer screening through Medicaid. The US Preventative Task Force (according to the CDC) has recommended other action items including genetic counseling for BRCA, increasing awareness for screening young women (an often neglected group), comprehensive benefits for maternity care, and removing underwriting from gender bias for new companies in the health insurance exchanges; however, comprehensive breast cancer screening has not been made explicit as an essential benefit standard that insurance companies will have to provide. Questions of sustainability and quality of care aside, the health reform bill has not only increased access in mass but has also made specific recommendations to tackle breast cancer as an outstanding issue.
Finally, in order to create long-lasting progress for screening, a public health education and awareness campaign will be vital. Certain studies done by Asnarulkahdi and colleagues show that community based incentives for breast cancer are tools to improve overall awareness. In these communities, they suggest a culture must be molded to make individuals comfortable with going for screenings to increase awareness of their own health. However, individual screening benefits are not enough. Asnarulkahdi and colleagues explain that individual involvement must spur community change by engaging in activities that increase awareness. Active participation will be needed on both internal and external levels. Today, we can see the benefits of programs like the Komen Race for the Cure, Relay for Life, Avonwalk, and National Breast Cancer Month in terms of increasing the visibility of the issue.
At the end of the day, breast cancer will require a multifaceted solution. It all starts with accurately identifying the problem and doing so in a cost effective and safe manner. At the same time, the community at large must be committed to executing what is necessary for national health.
Stojadinovic, A., Summers, T., Eberhardt, J. et. al. “Consensus Recommendation for Advancing Breast Cancer: Risk Identification and Screening in Ethnically Diverse Younger Women.” J Cancer (2011) 2: 210-227
Collins, S., Rustgi, S., and Doty, M. “Realizing Health Reform’s Potential: Women and the Affordable Care act of 2010.” The Commonwealth Fund (July 2010).
Centers for Disease Control and Prevention.“Cancer Screening – United States, 2010.” Morbidity and Mortality Weekly Report (2012) 61.3: 41-45
Asnarulkahdi, S. et al. “Community Participation in Breast Cancer Prevention Programs Towards Building Sustainable Programs: Involvement or Participation?” International Journal of Sustainable Development (2012) 3.3: 41-50
Kelly, K. and Richwald, G. “Automated Whole-Breast Ultrasound: Advancing the Performance of Breast Cancer Screening.” Seminars in Ultrasound, CT, MRI (2011) 32.4: 273-2