June 28th, 2012 by Hasham
Early Detection and Breast Cancer: What Every Woman Should Know
Breast cancer is the most common type of cancer among women in the United States. More than 182,000 women will be diagnosed with breast cancer this year. The chance of a woman having breast cancer sometime during her life is 1 in 8. Early detection is key in the treatment of breast cancer. There are steps you can take to detect breast cancer early when it is most treatable.
CancerCare recommends that every woman follow these screening guidelines:
MAMMOGRAPHY The most important screening test for breast cancer is the mammogram. A mammogram is an X-ray of the breast. It can detect breast cancer up to two years before the tumor can be felt by you or your doctor.
Women age 40 or older who are at average risk of breast cancer should have a mammogram once a year.
Women at high risk should have yearly mammograms along with an MRI starting at age 30.
CLINICAL BREAST EXAM (CBE) During a CBE, your doctor examines your breasts and the surrounding area for any possible signs of breast cancer. Your doctor checks for changes in the size or shape of your breasts, skin changes (including rashes, dimpling or redness), or other abnormal changes (such as lumps or discharge from the nipple).
Women in their 20s or 30s should have a CBE about every three years as part of a general health exam.
Women over 40 should have a CBE once a year.
BREAST SELF EXAM It is a good idea to get in the habit of doing monthly self-exams starting at age 20. Examining yourself on a regular basis lets you become familiar with your breasts so you will notice any changes that may occur.
Breast self-exams should not replace regular mammograms and clinical breast exams. To find out how to perform a breast self exam, ask your doctor.
Some Risk Factors for Breast Cancer
The following are some of the known risk factors for breast cancer. However, most cases of breast cancer cannot be linked to a specific cause. Talk to your doctor about your specific risk.
Age The chance of getting breast cancer increases as women age. Nearly 80 percent of breast cancers are found in women over the age of 50.
Personal history of breast cancer A woman who has had breast cancer in one breast is at an increased risk of developing cancer in her other breast.
Family history of breast cancer A woman has a higher risk of breast cancer if her mother, sister or daughter had breast cancer, especially at a young age (before 40). Having other relatives with breast cancer may also raise your risk.
Genetic factors Women with certain genetic mutations, including changes to the BRCA1 and BRCA2 genes, are at higher risk of developing breast cancer during their lifetime. Other gene changes may raise breast cancer risk as well.
Childbearing and menstrual history The older a woman is when she has her first child, the greater her risk of breast cancer. Also at higher risk are:
Women who menstruate for the first time at an early age (before 12)
Women who go through menopause late (after age 55)
Women who’ve never had children
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.
In this section of Understanding Breast Cancer, we discuss the pros and cons of each standard breast cancer screening test for women: mammography (including digital mammography), MRI and clinical breast exam. We also discuss what happens if a test shows something abnormal.
In rare cases, breast cancer can occur in men. Because men have much less breast tissue compared to women, the screening tools discussed in this chapter are not routinely used for men. Learn more about male breast cancer.
Early detection of breast cancer can improve the chances of successful treatment and recovery. To date, mammographic screening is the most reliable method to detect breast cancer in asymptomatic patients. Although highly effective, it has significant limitations, so that the development of more accurate, convenient, and objective detection methods is needed. In the absence of microcalcification, mammography often fails to detect tumors that are less than 5 mm in size, and also mammograms of women with dense breast tissue are difficult to interpret. For example, in a study of over 11,000 women with no clinical symptoms of breast cancer, the sensitivity of mammography was only 48% for the subset of women with extremely dense breasts, compared with 78% sensitivity for the entire sample of women in the study . In addition, when an abnormality has been detected, further tests involving invasive steps must complement mammography to establish whether the detected abnormality is a cancer.
A vast amount of literature is already available describing the potential use of large-scale gene expression analysis in disease diagnosis, including breast cancer [2-8]. However, most published work with implications in cancer diagnosis has involved clinical samples comprising either diseased tissues or cells. Obtaining such samples for clinical purposes requires a prior knowledge of both their presence and their location in the body. A gene-expression-based test to detect cancers that does not rely upon the availability of tissues or cells from the diseased area has not yet been described.
It has recently been suggested that circulating leukocytes can be viewed as scouts, continuously maintaining a vigilant and comprehensive surveillance of the body for signs of infection or other threats, including cancer . In line with this view, we show that peripheral blood can be used to develop a gene-expression-based test for early detection of breast cancer. The rationale for using blood cells as monitors for a malignant disease elsewhere in the body is based on the hypothesis that a malignant growth will cause characteristic changes in the biochemical environment of blood. These changes will affect the expression pattern of certain genes in blood cells.
In this pilot study, we have analyzed gene-expression patterns in peripheral blood cells of women diagnosed with breast cancer and women with no signs of this disease. We have identified a panel of genes with distinct expression patterns in cancer versus noncancer samples. The results indicate that breast cancer causes characteristic changes in the biochemical environment of blood already during early stages of disease development. Blood cells sense and respond to the change by decreasing the expression of genes involved in protein synthesis and increasing the expression of defense-related genes. We show that the expression pattern of the identified genes can be used to discriminate and predict the class of breast cancer and non-breast-cancer samples with high accuracy. Our findings should pave way for the development of a blood-based gene-expression test for early detection of breast cancer.
Early detection of breast cancer
This position statement applies to screening methods for the early detection of breast cancer in asymptomatic women (women without breast changes). The statement does not apply to diagnostic tests used to assess individual women presenting with breast changes.
Detection of breast cancer while it is still small and confined to the breast provides the best chance of effective treatment for women with the disease.1,2 Benefits of early detection include increased survival, increased treatment options and improved quality of life. For women, age remains the biggest risk factor in the development of breast cancer with over 70% of cases found in women aged 50 years and older.3 However, in younger women, tumours are likely to be larger and more aggressive and overall survival is lower than for older women with the disease.4,5 It is therefore important that women of all ages understand the importance of finding and treating breast cancer early.
The early detection methods covered by this position statement are:
breast awareness – awareness by a woman of the normal look and feel of her breasts
clinical breast examination – physical examination of an asymptomatic woman’s breasts by a medical or allied health professional
screening mammography – use of mammography in asymptomatic women to detect breast cancer at an early stage (BreastScreen Australia is the national mammographic screening program).
The position statement has two sections – a review of evidence to date about the benefits of these methods in reducing mortality from breast cancer, and recommendations based on this evidence. Recommendations are made for women of different ages who are at population risk*** and for women of all ages who are at increased risk**** of developing breast cancer. In making the recommendations, National Breast and Ovarian Cancer Centre (NBOCC)* has considered the importance of translating population-based evidence into messages that are relevant for individual women.
In Australia, even with a fully implemented mammographic screening program, more than half of breast cancers are diagnosed after investigation of a breast change found by the woman or by her doctor.7 This emphasises the importance of women being aware of the normal look and feel of their breasts and reporting unusual breast changes. Historically, public health campaigns have promoted specific techniques that women should use to examine their breasts (‘breast self-examination’). However, meta-analyses8-10 and randomised controlled trials11,12 have shown no difference in the size or stage of breast cancers at diagnosis or in the number of deaths from breast cancer for women taught to use a systematic approach for breast self-examination compared with those who did not receive instruction. These trials were conducted in Russia and China and involved large numbers of women. While the applicability of these trials for Australia has been questioned it is unlikely that trials of a similar size will be repeated in the future. It is also unlikely that a suitable control group would be found within the Australian population who have not already been exposed to messages about breast awareness and breast self-examination. A UK study13 of over 63,000 women aged 45–64 has shown no difference in the number of deaths from breast cancer after 16 years of follow-up between women taught to use a systematic approach to breast self-examination compared with those who did not receive instruction. Thus, while there is evidence that women can find breast changes due to early breast cancer, there is no evidence to promote the use of any one self-examination technique over another.