SCREENING FOR BREAST CANCER 2
Screening for Breast Cancer Using Mammography in Women Aged 40 Years and Older
Capstone Screening Project
Lindsay Ann Abrigo
Concordia University Nebraska
MPH 510 – Applied Epidemiology
Dr. Evelyn Davila
April 19, 2013
Screening for Breast Cancer Using Mammography in Women Aged 40 Years and Older
Breast Cancer is a cancer in that originates in the tissues of the breasts. In simpler terms, it is the uncontrolled growth of breast cells. The cancer forms when the cells in the tissues undergo a mutation or abnormal change. These mutations cause the nucleus within the cell to increase production at rapid rates. The cancer cells multiply and divide without control and the result of this uncontrolled growth is a tumor. There are two types of tumors, benign and malignant. A benign tumor is one that not dangerous to health and are not considered to be cancerous cells. These cells grow normally and do not generally spread through the rest of the body. However, a malignant tumor can become a potential risk to health. These cells grow at a rapid pace and if left unchecked may spread throughout the rest of the body.
Breast cancer does not usually have any symptoms in its early stages. This is why regular breast exams are vital for health. When the cancer grows, a breast lump will form. Often found on the armpit, usually a hard and uneven edged lump. The size, shape and feel of the breast or nipple may change. This is characterized by redness, dimpling of skin and looks similar to the skin of an orange. The mammary glands begin to swell causing a fluid discharged from the nipple. The fluid may appear to be puss-like, bloody or clear. For men, the symptoms include a breast lump, chest pain and tenderness. The pain can sometimes even make it hard to breathe, giving a feeling of shape pain within the chest. In the later stages of cancer, symptoms may include bone pain, breast pain or discomfort, swelling – usually the arm nearest the cancer, weight loss, and skin ulcers.
The exact causes of breast cancer are still a mystery. However, some of the primary risk factors are more noticeable. There is a higher risk for women than men, although men are still at risk but breast cancer is not as prevalent among men as it is among women. It has been considered to be genetic, knowing family history can help to see if a person is at risk of developing breast cancer. According to WebMD, “generally, women over 50 are more likely to get breast cancer than younger women, and African-American women are more likely than Caucasians to get breast cancer before menopause.”
Breast cancer is the most common cancer among women and also one of the leading causes of death among women of all races. One out of every eight women in the United States will develop breast cancer – just under 12 our of 100 women – as stated by Breastcancer.org (2012). According to the U.S. Cancer Statistics Working Group of the Centers for Disease Control and Prevention (2013), 211,731 women were diagnosed with breast cancer in 2009 and 40,676 women died of breast cancer.
Breast cancer screening means checking a woman’s breasts for cancer before there are signs or symptoms of the disease, according to the Centers for Disease Control and Prevention (2012). Getting regular screening tests is the best way for women to lower their risk of dying from breast cancer. Screening tests can find breast cancer early, when it's most treatable. The goal of screening exams for early breast cancer detection is to find the cancer before symptoms develop. Most doctors feel that early detection tests for breast cancer save many thousands of lives each year, asserts the National Breast Cancer Foundation, Inc. (2012). The Foundation maintains that many more lives could be saved if even more women and their health care providers took advantage of these tests (2012).
Three kinds of screening tests are used to screen the breasts for cancer: mammogram, clinical breast exam (CBE), and breast self-exam. A mammogram is an x-ray of the breast. According to the CDC (2012), mammograms are the best method to detect breast cancer early when it is easier to treat and before it is big enough to feel or cause symptoms. Having regular mammograms can lower the risk of dying from breast cancer. Not all organizations agree on mammogram guidelines. For instance, the U.S. Preventive Services Task Force mammogram guidelines recommend women begin screening at age 50 and repeat the test every two years. The American Cancer Society and other organizations recommend screening begin at 40 and continue annually.
Women aged 40 and older should have a mammogram every year and should continue to do so for as long as they are in good health. Mayo Clinic (2012) supports screening beginning at age 40 because screening mammograms can detect breast abnormalities early in women in their 40s. Dr. Sandhya Pruthi, an internist at Mayo Clinic, cites findings from a large study in Sweden of women in their 40s who underwent screening mammograms showed a decrease in breast cancer deaths by 29 percent (2012). A mammogram can miss some cancers, and it may lead to follow up of findings that are not cancer (U.S. National Library, 2010). Another study, according to Pruthi (2012), concluded that despite more women being diagnosed with early breast cancer due to mammogram screening, the number of women diagnosed with advanced breast cancer hasn't decreased. The study also suggested that some women with early breast cancer were diagnosed with cancer that may never have affected their health. Despite their limitations, mammograms are still a very effective and can potentially lower the risk of dying from breast cancer. The CDC (2012) recommends that women aged 50 to 74 years have a screening mammogram every two years and women aged 40–49 years should talk to their doctor about when and how often a screening mammogram should be done.
A clinical breast exam (CBE), as defined by WebMD (2012), is a breast examination by a health professional such as a doctor, nurse practitioner, nurse, or physician assistant. Women in their 20s and 30s should have a clinical breast exam, CBE, as part of a periodic health exam by a health professional preferably every three years (WebMD, 2012). A CBE may be recommended more frequently if a woman has a strong family history of breast cancer. For this exam, the health professional will first look at the breasts for abnormalities in size or shape, or changes in the skin of the breasts or nipple. Then, using the pads of the fingers, the examiner will gently feel the breasts. Special attention will be given to the shape and texture of the breasts, location of any lumps, and whether such lumps are attached to the skin or to deeper tissues. The area under both arms will also be examined. The CBE is a good time for women who don't know how to examine their breasts to learn the right way to do it from their health care professionals.
CBE is done along with mammograms and offers a chance for women and their doctor or nurse to discuss changes in their breasts, early detection testing, and factors in the woman's history that might make her more likely to have breast cancer. There may be some benefit in having the CBE shortly before the mammogram. The exam should include instruction for the purpose of getting more familiar with your own breasts. Women should also be given information about the benefits and limitations of CBE and breast self-examination. The chance of breast cancer occurring is very low for women in their 20s and gradually increases with age.
Breast self-examination, BSE, is an option for women starting in their 20s (WebMD, 2012). Women should report any breast changes to their health professional right away. Research has shown that BSE plays a small role in finding breast cancer compared with finding a breast lump by chance or simply being aware of what is normal for each woman. Doing BSE regularly is one way for women to know how their breasts normally look and feel and to notice any changes. The goal, with or without BSE, is to report any breast changes to a doctor or nurse right away. By doing the exam regularly, you get to know how your breasts normally look and feel and you can more readily find any changes. If a change occurs, such as development of a lump or swelling, skin irritation or dimpling, nipple pain or retraction (turning inward), redness or scaliness of the nipple or breast skin, or a discharge other than breast milk (such as staining of your sheets or bra), you should see your health care professional as soon as possible for evaluation (U.S. National Library, 2010).
Women at high risk (greater than 20% lifetime risk) should get an MRI and a mammogram every year. Women at moderately increased risk (15% to 20% lifetime risk) should talk with their doctors about the benefits and limitations of adding MRI screening to their yearly mammogram (WebMD, 2012). Yearly MRI screening is not recommended for women whose lifetime risk of breast cancer is less than 15%. If MRI is used, it should be in addition to, not instead of, a screening mammogram. This is because although an MRI is a more sensitive test (it's more likely to detect cancer than a mammogram), it may still miss some cancers that a mammogram would detect.
For most women at high risk, screening with MRI and mammograms should begin at age 30 years and continue for as long as a woman is in good health. But because the evidence is limited regarding the best age at which to start screening, this decision should be based on shared decision-making between patients and their health care providers, taking into account personal circumstances and preferences.
Several risk assessment tools, with names such as the Gail model, the Claus model, and the Tyrer-Cuzick model, are available to help health professionals estimate a woman's breast cancer risk. The Gail model bases its risk estimates on certain personal risk factors, like current age, age at menarche, or first menstrual period, and history of prior breast biopsies, along with any history of breast cancer in first-degree relatives (American Cancer Society, Inc, 2013). The Claus model estimates risk based on family history of breast cancer in both first and second-degree relatives (American Cancer Society, Inc, 2013). These tools give approximate, rather than precise, estimates of breast cancer risk based on different combinations of risk factors and different data sets. As a result, they may give different risk estimates for the same woman. Both the doctor and patient should discuss the results together when deciding whether to begin MRI screening. There is currently no known evidence that an MRI will be an effective screening tool for women at average risk.
The sensitivity of mammography is the percentage of breast cancers detected in a given population, when breast cancer is present. Sensitivity depends on tumor size, conspicuity, and hormone sensitivity as well as breast tissue density, patient age, and timing within the menstrual cycle, overall image quality, and interpretive skill of the radiologist. Overall sensitivity is approximately 79% but is lower in younger women and in those with dense breast tissue (National Cancer Institute, 2013). The specificity of mammography is the likelihood of the test being normal when cancer is absent, whereas the false-positive rate is the likelihood of the test being abnormal when cancer is absent. If specificity is low, many false-positive examinations result in unnecessary follow-up examinations and procedures (National Cancer Institute, 2013).
The American Cancer Society (2013) believes the use of mammograms, MRIs – specifically for women at high risk, clinical breast exams, and finding and reporting breast changes early, according to the recommendations aforementioned, offers women the best chance to reduce their risk of dying from breast cancer. This approach is clearly better than any one exam or test alone. Without question, a physical exam of the breast without a mammogram would miss the opportunity to detect many breast cancers that are too small for a woman or her doctor to feel but can be seen on mammograms. Mammograms are a sensitive screening method, but a small percentage of breast cancers do not show up on mammograms but can be felt by a woman or her doctors. For women at high risk of breast cancer, both mammography and MRI exams of the breast are recommended.
The primary objective of public health and public health professionals should be to advocate for more constructed and coordinated action to increase awareness among women of all ages about the incidence of breast cancer. It is the hope to significantly increase awareness of breast cancer at all levels at society from family members, friends, general public, and the medical professional community. Emphasis will be placed on the importance of early detection through education and implementation of regular breast cancer screening methods such as mammograms, clinical breast exams, self-breast exams, and MRIs, if necessary. All levels of society should be provided with the necessary information and basic knowledge that is crucial to gain an adequate understanding of breast cancer and its effect on women – and men – of all ages.
References
American Cancer Society, (2013). Breast cancer: early detection. Retrieved from http://www.cancer.org/Cancer/BreastCancer/MoreInformation/BreastCancerEarlyDetection/breast-cancer-early-detection-toc
Breastcancer.org. (2012, October 30).U.S. breast cancer statistics. Retrieved from http://www.breastcancer.org/symptoms/understand_bc/statistics
Centers for Disease Control and Prevention, Division of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion. (2012).Breast cancer screening. Retrieved from website: http://www.cdc.gov/cancer/breast/basic_info/screening.htm