October is Breast Cancer Awareness Month
According to the American Cancer Society, breast cancer is the most common cancer among American women, except for skin cancers. The chance of developing invasive breast cancer at some time in a woman's life is about 1 in 8 (12%). In 2012, an estimated 226,870 women will be diagnosed with breast cancer in the United States.
Breast cancer is the second leading cause of cancer death in women, exceeded only by lung cancer. The good news is that breast cancer is a disease that can be treated and cured. Death rates from breast cancer have been declining since about 1990, with larger decreases in women younger than 50. At this time there are about 2.6 million breast cancer survivors in the United States. (This includes both women still being treated and those who have completed treatment.) Treatment for breast cancer includes surgery, radiation, chemotherapy, endocrine/anti-hormone therapy and clinical trials.
Source: American Cancer Society (ACS): What are the key statistics about breast cancer?
Breast Cancer Risk Factors
A risk factor is anything that affects your chance of getting a disease, such as cancer. Most women who have one or more breast cancer risk factors never develop the disease, while many women with breast cancer have no apparent risk factors (other than being a woman and growing older). Even when a woman with risk factors develops breast cancer, it is hard to know just how much these factors may have contributed to her cancer.
There are different kinds of risk factors. Some factors, like a person's age or race, can't be changed. Others are linked to cancer-causing factors in the environment. Still others are to related personal behaviors, such as smoking, drinking, and diet. Some factors influence risk more than others, and your risk for breast cancer can change over time, due to factors such as aging or lifestyle.
Studies have found the following risk factors for breast cancer:
Risk factors you cannot change:
Simply being a woman is the main risk factor for developing breast cancer. Although women have many more breast cells than men, the main reason they develop more breast cancer is because their breast cells are constantly exposed to the growth-promoting effects of the female hormones estrogen and progesterone. Men can develop breast cancer, but this disease is about 100 times more common among women than men.
Your risk of developing breast cancer increases as you get older. About 1 out of 8 invasive breast cancers are found in women younger than 45, while about 2 out of 3 invasive breast cancers are found in women age 55 or older.
- Genetic risk factors:
About 5% to 10% of breast cancer cases are thought to be hereditary, resulting directly from gene defects (called mutations) inherited from a parent. Visit our Breast and Ovarian Risk Evaluation web pages for more information about genes and DNA. The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 and BRCA2 genes.
- Family history of breast cancer:
Breast cancer risk is higher among women whose close blood relatives have this disease. Having one first-degree relative (mother, sister, or daughter) with breast cancer approximately doubles a woman's risk. Having 2 first-degree relatives increases her risk about 3-fold.
- Race and ethnicity:
White women are slightly more likely to develop breast cancer than are African-American women. African-American women are more likely to die of this cancer. At least part of this seems to be because African-American women tend to have more aggressive tumors, although why this is the case is not known. Asian, Hispanic, and Native-American women have a lower risk of developing and dying from breast cancer.
- Dense Breast Tissue:
Women with denser breast tissue (as seen on a mammogram) have more glandular tissue and less fatty tissue, and have a higher risk of breast cancer. Unfortunately, dense breast tissue can also make it harder for doctors to spot problems on mammograms.
- Certain benign breast conditions:
Women diagnosed with certain benign breast conditions may have an increased risk of breast cancer. Some of these conditions are more closely linked to breast cancer risk than others.
- Lobular carcinoma in situ:
Women with lobular carcinoma in situ (LCIS) have a 7- to 11-fold increased risk of developing cancer in either breast.
- Menstrual periods:
Women who have had more menstrual cycles because they started menstruating at an early age (before age 12) and/or went through menopause at a later age (after age 55) have a slightly higher risk of breast cancer. This may be related to a higher lifetime exposure to the hormones estrogen and progesterone.
- Previous chest radiation:
Women who, as children or young adults, had radiation therapy to the chest area as treatment for another cancer (such as Hodgkin disease or non-Hodgkin lymphoma) are at significantly increased risk for breast cancer. This varies with the patient's age when they had radiation.
- Diethylstilbestrol exposure:
From the 1940s through the 1960s some pregnant women were given the drug diethylstilbestrol (DES) because it was thought to lower their chances of miscarriage (losing the baby). These women have a slightly increased risk of developing breast cancer. Women whose mothers took DES during pregnancy may also have a slightly higher risk of breast cancer.
Lifestyle-related factors and breast cancer risk:
- Having children:
Women who have had no children or who had their first child after age 30 have a slightly higher breast cancer risk. Having many pregnancies and becoming pregnant at a young age reduce breast cancer risk. Pregnancy reduces a woman's total number of lifetime menstrual cycles, which may be the reason for this effect.
- Recent oral contraceptive use:
Studies have found that women using oral contraceptives (birth control pills) have a slightly greater risk of breast cancer than women who have never used them. This risk seems to decline back to normal over time once the pills are stopped.
- Hormone therapy after menopause:
The increased risk from combined hormone therapy appears to apply only to current and recent users. A woman's breast cancer risk seems to return to that of the general population within 5 years of stopping combined treatment.
Some studies suggest that breast-feeding may slightly lower breast cancer risk, especially if breast-feeding is continued for 1½ to 2 years.
The use of alcohol is clearly linked to an increased risk of developing breast cancer. The risk increases with the amount of alcohol consumed.
- Physical activity:
Evidence is growing that physical activity in the form of exercise reduces breast cancer risk.
Source: American Cancer Society (ACS) Learn About Breast Cancer webpage.
Breast Cancer Symptoms
Early breast cancer usually doesn't cause symptoms. But as the tumor grows, it can change how the breast looks or feels. The common changes include:
- A lump or thickening in or near the breast or in the underarm area
- A change in the size or shape of the breast
- Dimpling or puckering in the skin of the breast
- A nipple turned inward into the breast
- Discharge (fluid) from the nipple, especially if it's bloody
- Scaly, red, or swollen skin on the breast, nipple, or areola (the dark area of skin at the center of the breast).
- Dimples in the breast that look like the skin of an orange, called peau d'orange.
You should see your health care provider about any symptom that does not go away. Most often, these symptoms are not due to cancer. Another health problem could cause them. If you have any of these symptoms, you should tell your health care provider so that the problems can be diagnosed and treated.
Source: Natiional Cancer Institute (NCI)
Screening for Breast Cancer
Screening refers to tests and exams used to find a disease, like cancer, in people who do not have any symptoms. The goal of screening exams, such as mammograms, is to find cancers before they start to cause symptoms. Breast cancers that are found because they can be felt tend to be larger and are more likely to have already spread beyond the breast. In contrast, breast cancers found during screening exams are more likely to be small and still confined to the breast. The size of a breast cancer and how far it has spread are important factors in predicting the prognosis (outlook) for a woman with this disease.
American Cancer Society breast screening guidelines
- Women age 40 and older should have a screening mammogram every year and should continue to do so for as long as they are in good health.
- Women in their 20's and 30's should have a clinical breast exam (CBE) as part of a periodic (regular) health exam by a health professional, at least every 3 years. After age 40, women should have a breast exam by a health professional every year.
- Breast self exam (BSE) is an option for women starting in their 20's. Women should be told about the benefits and limitations of BSE. Women should report any breast changes to their health professional right away.
Source: American Cancer Society (ACS) Can breast cancer be found early?
NCCN Breast Screening guidelines
Women at Normal Risk
- For women between ages 20 and 39 years, a clinical breast examination every 1-3 years is recommended, with breast awareness encouraged.
- For women aged 40 years and older, annual clinical breast examination and screening mammography are recommended, with breast awareness encouraged.
- Upper age limit for screening not established.
Source: National Comprehensive Cancer Network (NCCN) Breast Cancer Screening and Diagnosis [PDF]
Clinical Breast Exam
An exam of the breast by a doctor or other health professional. The doctor will carefully feel the breasts and under the arms for lumps or anything else that seems unusual.
Mammograms are x-ray pictures of the breast that are effective for finding breast cancer. Mammograms can be used to check for breast cancer in women who have no signs or symptoms of the disease. This type of mammogram is called a screening mammogram. Mammograms also can be used to check for breast cancer after a lump or other sign or symptom of the disease has been found. This type of mammogram is called a diagnostic mammogram.
Source: National Cancer Institute (NCI) Understanding Mammograms and Your Risk of Breast Cancer and General Information About Breast Cancer.