Women with severe, chronic health issues are screened for breast cancer less often
Women with severe disabilities and multiple chronic conditions are screened for breast cancer less often than women with no disabilities or no chronic conditions, a new study has found.
They are also screened less often than women with moderate disabilities or women with only one chronic condition, according to Dr. Sara Guilcher, an affiliate scientist with the Li Ka Shing Knowledge Institute of St. Michael’s Hospital.
Dr. Guilcher said women with disabilities often have other measures of social vulnerability, such as low income and low education levels.
Her research, published in the journal Preventive Medicine, is consistent with other studies showing that low income and education were also associated with lower breast cancer screening rates. Previous research has also shown that having a certain level of disability is associated with higher breast cancer screening rates, perhaps because those women have more frequent contact with the health care system.
However, in contrast to previous research, this study identified higher screening rates for women with moderate disabilities compared to those with severe disabilities – who also have greater contact with physicians than other women with no disabilities.
“Despite the presence of a universal health insurance system in Ontario, our research highlights the persistence of significant health disparities in breast cancer screening, particularly for women who are more vulnerable due to severe disability, multiple chronic conditions, low income and lower education,” said Dr. Guilcher, who has a PhD in Clinical Epidemiology at the Institute of Health Policy, Management and Evaluation, University of Toronto.
The highest rate of screening was 75 per cent, which was among women with moderate level of disability and one chronic condition. Women with severe disability, across levels of chronic conditions, had the lowest rate of breast cancer screening at 61 per cent. Women with two or more chronic conditions were screened particularly less often.
“Women who are at a lower socioeconomic position may be less likely to be assertive and to be strong advocates for their health care management,” said Dr. Guilcher.
Breast Cancer Screening Tests
Breast cancer screening can involve a number of different types of examinations. These include:
Breast Self Examination
During a breast self-examination (BSE), a woman checks her own breasts for any irregularities, which may include lumps, changes in breast size or shape, nipple discharge, or irregular tissue thickening. Despite attempts by investigators to demonstrate the impact of BSE on reducing breast cancer deaths, no study has been able to show a statistically significant reduction. As a result, our doctors and a number of national organizations no longer aggressively encourage women to perform BSE. However, because BSE is easy and free, and may detect some cancers, women are not discouraged from performing regular BSE.
Clinical Breast Examination
A clinical breast examination (CBE) is a physical examination of the breast performed by a health professional. In clinical studies where CBE was performed along with mammography, the reduction in deaths from breast cancer was similar to the reduction in those women who received mammography alone. This suggests that CBE adds little to mammography in reducing breast cancer deaths.
Mammography
Mammography is the diagnostic examination of the breast using low-dose x-rays. Annual mammogram screenings have been shown to reduce significantly the number of women dying from breast cancer in the age group 40 years and older. Until fairly recently, all mammograms used the conventional film-based technique, which utilizes x-rays to produce an image of the breast on film. Introduced in the United States in 2001, digital mammography also uses x-rays but captures the image on a computer, where it can be viewed and manipulated for contrast. While finding no significant difference between the two techniques when applied to the general population and for most women over 50, studies have shown that digital mammograms detected more cancers in three specific groups: women under 50, women with dense breasts, and women not yet in menopause.
Ultrasound
Ultrasound, also known as ultrasonography, is an imaging method in which high-frequency sound waves are used to create images of blood vessels, tissues, and organs including the breast. Breast ultrasound is often used to evaluate breast abnormalities that are found during mammography or a clinical breast exam. The accuracy of breast ultrasound is highly dependent on the skill level and training of the ultrasound technician. This creates an increased risk of false positives, requiring follow-up exams and biopsy — which can be expensive and lead to unnecessary anxiety for the patient. Thus far, there are no data to establish that annual screening with ultrasound will reduce breast cancer mortality. However, there may be a subpopulation of high-risk women with dense breasts in whom the benefits outweigh the risks, and there is an ongoing multicenter study evaluating the use of ultrasound in this group. Currently, it is not the standard of care to offer or perform this examination.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a diagnostic procedure that uses a magnetic field to provide three-dimensional images of internal body structures, including the breast. MRI is expensive and requires the injection of intravenous contrast dyes. Recent studies of women with an inherited risk of breast cancer have shown that MRI has a higher sensitivity in detecting breast cancers than other screening methods. However, there are no study data showing that MRI screening reduces the number of breast cancer deaths.
Dr. Guilcher noted that in Ontario, women can refer themselves to the Ontario Breast Screening Program, which sends them reminders of when they are due for mammograms and can provide results at the same time the test is done. Further research could explore the demographics of the women who enrol in this program, she said.
Dr. Guilcher said that worldwide, breast cancer is the most prevalent cancer among women and the second leading cause of cancer-related deaths. Deaths have significantly dropped due to advances in prevention and treatment. In Ontario, mortality rates fell 37 per cent for women between the ages of 50 and 74 between 1990 and 2009.
Her study was done in conjunction with the Institute for Clinical Evaluative Studies (ICES), based on health records of 10,363 women in Ontario ages 50-69 whose health records are stored in databases at ICES.
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This research was supported by a research grant from the Ontario Ministry of Health and Long Term Care (MOHLTC) to the Health System Performance Research Network and by the MOHLTC support for ICES.
About St. Michael’s Hospital
St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.
About ICES
ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.
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