Breast cancer is the second most common cancer among American women and the second most common cause of cancer deaths—behind lung cancer. In 2014 over 236,968 women were diagnosed with breast cancer and that same year over 41,000 deaths occurred as a result of breast cancer. For more information regarding the role of breast cancer in women’s health see the CDC website at http://www.cdc.gov/nchs/fastats/deaths.htm.
Current information suggests that as many as one in eight women have a lifetime probability of developing breast cancer and one in nine will develop invasive breast cancer. The reason for the difference is that some women develop a very early stage of breast cancer called DCIS (ductal carcinoma in situ), which is non-invasive.
Since the early 1980s the incidence of breast cancer had risen and probably reflected the results of increasing public awareness of the need for screening mammograms. As a result of vigorous public awareness campaigns breast cancer is increasingly diagnosed in its early stages when it is more likely to be cured. Fortunately, the incidence of breast cancer in the past few years has actually declined slightly.
About one-half of breast cancer cases can be explained by known risk factors such as age of onset of menstrual periods, age at menopause and various benign diseases of the breast. Another 10% of breast cancers are associated with a positive family history.
What are the risk factors for breast cancer?
The risk factors for breast cancer include:
The incidence of breast cancer rises sharply with age until about the age of 45-50 when the rise continues but at a less pronounced rate. The incidence increases with age until about age 75-80 at which time it doesn’t appear to change much.
Race and Ethnicity
The highest rates of breast cancer occurs in Caucasian women (141 cases per 100,000 women. The rates are lower in African American women (119 per 100,000), Asian women (97 per 100,000), Hispanic/Latina women (90 per 100,000) and American Indians (55 per 100,000). Despite the fact that African-American women have a lower incidence of breast cancer than Caucasian women they have a higher mortality rate from breast cancer. This may be due to the advanced stage of the disease at the time of its discovery and may also be due to a more aggressive form of the cancer found in African American women
Benign breast disease
There is an increased likelihood of breast cancer in women with benign conditions of the breast that fall into a category known as “proliferative lesions”. This does not include fibrocystic change. About one in twenty breast lumps, when biopsied, reveal ‘atypical hyperplasia’. This means the cells are not cancer, but are growing abnormally. Atypical hyperplasia does increase your risk of breast cancer by 2-5 times the average.
Women of higher socioeconomic status are at greater risk for breast cancer. This may reflect the fact that women of a higher educational, occupational and economic status tend to delay childbearing, have fewer children and have their first child later in life. This trend may also reflect the fact that these same women tend to utilize mammography more often than women in lower socioeconomic classes.
Lifestyle and Dietary factors
Moderate alcohol intake increases the risk of certain types of breast cancer and this effect appears to be more pronounced in women who take hormone replacement therapy.
The Nurse’s Health Study revealed an association between large amounts of red meat intake and certain pre-menopausal breast cancers. There is also some information that intake of low-fat dairy products may protect against breast cancer.
Despite the relationship between caffeine intake and benign fibrocystic disease of the breast, there is no relationship between caffeine intake and breast cancer.
Women with a higher body mass index (BMI) have an increased risk of post-menopausal breast cancer. Women who weight over 80 kg (176 lbs) have a 25% increased risk of breast cancer compared to women who weigh less than 60 kg (132 lbs). Obesity also increases the risk of mortality from breast cancer.
Women over 5’9″ tall are 20% more likely to develop breast cancer than women under 5’3″ tall.
Age at onset of menses and age of menopause
Early onset of menstrual periods and late menopause seem to be associated with an increased risk of breast cancer. It appears that the longer a woman is exposed to estrogens the greater the likelihood of developing breast cancer. Women, for instance, that undergo removal of both ovaries before the age of 40 reduce their lifetime risk of breast cancer by 50%.
Women who’ve never given birth to a child have a 1.2 to 1.7 relative risk of developing breast cancer.
Age at first delivery
The younger a woman is at the time of her first delivery the less likely she is of developing breast cancer.
The best available data compiled by the National Cancer Institute concludes that there is no relationship between a history of an elective abortion(s) and subsequent development of breast cancer. See www.cancer.gov/cancerinfo/ere)
There does seem to be some protective effect of breast feeding against developing breast cancer. This appears to be related to the length of breast feeding and the number of children nourished in this fashion.
There also seems to be a relationship between low bone density and a lower incidence of breast cancer. The common culprit may be estrogen. Low levels of estrogen are bad for bone density but may be protective against breast cancer.
Hormone Replacement Therapy
The exact relationship between hormone replacement therapy and breast cancer is still a subject of debate. The Women’s Health Initiative Study, published in 2002 (http://www.nhlbi.nih.gov/whi/) did conclude that there was an important relationship between breast cancer and the use of estrogen and progestin replacement therapy.
A positive family history is only reported by 15-20% of women diagnosed with breast cancer. The risk of breast cancer for a woman with one affected first-degree relative (mother or sister) is 1.8 times that of women without a family history. With two affected first degree relatives the risk increases to 2.93-fold. The risk is greatest in women whose relative was diagnosed before the age of 30.
BRCA1 and BRCA2 are major genes related to hereditary breast cancer. In some studies women with inherited BRCA1 or BRCA2 mutations have up to an 80% chance of developing breast cancer during their lifetime and are more likely to have it at a younger age than women who are not born with one of these gene mutations. Women who have inherited certain mutations in these genes have a high risk of developing breast, ovarian and several other types of cancer during the course of their lives. Melanoma and lymphoma are also more common among people who have BRCA2 mutations. BRCA mutations are found most often in Jewish women of Ashkenazi (Eastern Europe) origin but are also seen in African American and Hispanic women.
History of radiation therapy to the chest
This includes women who’ve undergo radiation therapy to the chest for Hodgkins disease. The risk is increased in women who’ve undergone radiation between the ages of 10 and 30.
Additional risk factors
Other risk factors for breast cancer include a history of uterine, ovarian or colon cancer. Also, a prior history of breast cancer increases the predisposition toward developing future disease.
How can I calculate my own risk of developing breast cancer?
You can even go on line at http://www.cancer.gov/bcrisktool/ and use a calculation tool that will help you determine your own individual risk for developing this disease.
What are the symptoms of breast cancer? Fortunately, modern screening allows most women to detect cancers well before they produce any symptoms. However, it’s important to consult a health care provider should you have any of these symptoms.
- Breast lump—usually painless, firm to hard and often with irregular borders.
- Lump or mass in the armpit
- A change in the size or shape of the breast
- Abnormal nipple discharge (bloody, clear-to-yellow, greenish or one that looks like pus.
- A change in the color or feel of the skin of the breast, nipple or areola
- Breast pain, enlargement or discomfort on one side only
- Development of nipple retraction
What is breast cancer screening?
Screening for breast cancer involves non-invasive testing to determine whether or not a woman has a suspicious lesion that requires biopsy. This is different than diagnosing breast cancer. The diagnosis of breast cancer can only be made by the study of a biopsy specimen.
By design, screening tests are meant to be used on large populations of women and are, generally speaking, not painful and non-invasive. Examples of screening tests include physical exam, mammography, ultrasound, MRIs and even three-dimensional mammography of the breasts.
If any of these non-invasive tests suggest the possibility of a cancerous or pre-cancerous lesion then more invasive diagnostic tests are suggested. These tests may involve the needle-aspiration of a cyst, a guided (stereotactic) core biopsy of the breast or a simple surgical excision of a suspected lesion.
In summary, screening tests, such as physical examination, mammography, MRI and ultrasound do not diagnose cancer. These tests identify that small subset of patients that need to undergo further more invasive testing. The actual diagnosis of breast cancer is always made with a tissue specimen that is studied under the microscope by a trained pathologist.
When should breast cancer screening begin?
Women should begin yearly mammogram screening every year beginning at age 40 and continue to do so for as long as they are in good health. Mammograms have limitations and often require the use of supplemental tests such as ultrasound of the breasts as well as occasional breast biopsies.
What if I’m at high risk? When should I start routine screening?
Women who are at high risk for developing breast cancer should begin screening at age 30-35. Because the scientific data is limited regarding the best age to begin screening in “high-risk” women the decision should be made between patients and their health care providers. Some centers suggest that women with a greater than 20% lifetime risk of developing breast cancer should also get an MRI along with a mammogram every year. Women at high risk include those who
- Have a known BRCA1 or BRCA2 gene mutations
- Have a first degree relative (mother, father, brother, sister, or child) with a BRCA1 or BRCA2 mutation and have not had genetic testing themselves.
- Have a lifetime risk of breast cancer of 20% or more.
- Have a history of radiation therapy to the chest when they were between the ages of 10 and 30 years old.
Where do I go for breast cancer screening?
There are many good facilities for breast cancer screening in our region. Here are the names of a few that we work closely with.
Please be certain that all reports are sent to our office.