Understanding Breast Cancer
Each year there are more than 276,000 women diagnosed with invasive breast
cancer. There are more than 2,600 cases diagnosed in men. Breast cancer
is the most frequently diagnosed cancer in women aside from skin cancer.
Additionally, there will be more than 48,000 new cases of in situ breast cancer.
Being female and aging are the two most important risk factors for breast
cancer. There is a common misconception among older women that their risk
decreases with age when in fact the opposite is true.
Having one or more risk factors does not mean that you will develop breast
cancer, in fact most women who have one or more risk factors never develop
the disease. Many women with no risk factors develop breast cancer, at
this time we don’t know how much these risk factors contribute to
the development of breast cancer.
There are different kinds of risk factors, some of these are under our
control and can be changed. Risk factors, like age or race, cannot be
changed. Other risk factors are linked to the environment. Your risk for
breast cancer can change over time, due to factors such as aging or lifestyle changes.
Risk Factors You Cannot Change
Being a woman is the main risk factor for developing breast cancer. The
primary reason women develop breast cancer is because the breast cells
are constantly exposed to the effects of female hormones, estrogen and
progesterone. Breast cancer is also found in men but in much lower numbers
than in women.
As you age your risk of developing breast cancer increases. About 1 out
of 8 invasive breast cancers are found in women younger than 45, while
2 of 3 invasive breast cancers are found in women age 55 or older.
Genetic Risk Factors
Hereditary breast cancer accounts for 5%-10% of cases, they are thought
to be hereditary, resulting from gene mutations inherited from a parent.
These can be inherited from either your Mother or your Father.
BRCA1 and BRCA2: An inherited mutation in the BRCA1 and BRCA2 genes is the most common hereditary
risk factor for developing breast cancer. The risk may be as high as 80%
for members of some families with BRCA mutations; they are also at an
increased risk for ovarian cancer. These cancers tend to occur in younger
women and more often affect both breasts than cancers in women who are
not born with one of these gene mutations. These mutations can occur in
any racial or ethnic group, however in the United States the BRCA mutations
are most often found in Jewish women with Ashkenazi(Eastern Europe) heritage.
Genetic testing: Genetic testing can be done to look for mutations in the BRCA1 and BRCA2
genes and is covered by most health insurance plans as long as you meet
the criteria for testing. It is important that you speak with a genetic
counselor, nurse, or physician who is qualified to explain the results
of the tests. Although testing may be helpful in some situations, the
pros and cons need to be considered carefully.
Family History of Breast Cancer
Having a first-degree relative (mother, sister, or daughter) with breast
cancer almost doubles a woman's risk. Having 2 first-degree relatives
triples her risk.
Personal History of Breast Cancer
A woman with a personal history of cancer in one breast has an increased
risk of developing a new cancer in the other breast or in another part
of the same breast. This is called a second primary cancer and is different
from a recurrence of the first cancer.
Race and Ethnicity
Statistics show that white women are slightly more likely to develop breast
cancer than African-American women, but show that African-American women
are more likely to die from breast cancer.
If we look at the statistics by age, we find that breast cancer is more
common in women who are under 45 years of age. It is also shown that 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. If you have dense breasts you should discuss
the appropriate imaging studies available to you. The introduction of
3D technology has shown an improvement in imaging studies for women with
dense breasts. This technology is available at the Margaret W. Niedland
Breast Center, call 561- 263-4414 to schedule an appointment.
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.
These conditions show excessive growth of cells in the ducts or lobules
of the breast tissue and seem to increase a woman’s risk of breast
- Usual ductal hyperplasia (without atypia)
- Complex fibroadenoma
- Sclerosing adenosis
- Several papillomas or papillomatosis
- Radial scar
These conditions also show excessive growth of cells in the ducts or lobules
of the breast tissue, with some of cells no longer appearing normal. They
have a stronger effect on the risk of developing breast cancer.
- Atypical ductal hyperplasia (ADH)
- Atypical lobular hyperplasia (ALH)
Women with a family history of breast cancer and either hyperplasia or
atypical hyperplasia have an even higher risk of developing a breast cancer.
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.
Women who started menstruating at an early age (before age 12) and/or went
through menopause at a later age (after age 55) causing them to have had
more menstrual cycles have a slightly higher risk of breast cancer. The
increase in risk may be due to a longer lifetime exposure to the hormones
estrogen and progesterone.
Previous Chest Radiation
For women who had radiation as a child or an adolescent as a treatment
for cancer have a significantly increased risk for breast cancer. This
varies with the age of the patient when they received the radiation. If
chemotherapy was also part of the treatment, it may have stopped ovarian
hormone production for some time, lowering the risk. The risk of developing
breast cancer from chest radiation is highest if the radiation was given
during adolescence, when the breasts were still developing. Radiation
treatment after age 40 does not seem to increase breast cancer risk.
Diethylstilbestrol (DES) Exposure
The use of DES from the 1940s through the early 1970s for pregnant women
to lower their risk of miscarriage has shown a slightly increased risk
of developing breast cancer. 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.
Women who do not have children or who had their first child after age 30
have a slightly higher breast cancer risk. Women who became pregnant at
an early age or have many children are at a reduced risk for breast cancer.
Because pregnancy reduces a woman’s menstrual cycles over her lifetime
it is thought to be the reason for the reduced risk.
Recent Oral Contraceptive Use
Studies show that women using oral contraceptives (birth control pills)
have a slightly greater risk of breast cancer than women who have never
used them. Once the pills are stopped the risk will return to normal over
time. If the pills were stopped over ten years ago then there does not
appear to be an increased risk. If you use oral contraceptives or are
considering using them you should discuss the risks and benefits with
Hormone Therapy After Menopause
Hormone replacement therapy has been used for many years to relieve symptoms
of menopause and help prevent osteoporosis. Estrogen and sometimes progesterone
are prescribed. Early studies suggested these hormones might have other
health benefits as well, but those benefits have not been found in more
recent, better designed studies.
Women who still have a uterus are generally given estrogen and progesterone;
this is called combined hormone therapy. Progesterone is used because
using estrogen alone increases the risk of uterine cancer. Women who have
had a hysterectomy and no longer have a uterus can take estrogen alone.
Combined HT: Large studies have shown that the use of combined post-menopausal hormone
therapy increases the risk of getting breast cancer and the likelihood
that it may be found at a more advanced stage. The increased risk from
combined HT appears to apply only to current and recent users. Within
five years of stopping hormone therapy a woman’s risk appears to
return to that of the general population.
Bioidentical hormones have been marketed as a safe alternative to estrogen
and progesterone. There are very few studies comparing bioidentical hormones
to synthetic hormones and no evidence to support that are safer to use.
Until studies prove otherwise, the use of these hormones should be assumed
to carry the same health risks as any other type of hormone therapy.
Estrogen Therapy: The use of estrogen therapy does not appear to increase the risk of developing
breast cancer. Some studies have found that long term use of estrogen
alone (10 years or longer) increases the risk of breast and ovarian cancer.
Other than the short-term relief of menopausal symptoms, there appears
to be little support for the use of either Combined Hormone Therapy or
Estrogen Therapy. Aside from the increased risk of breast cancer, combined
HT also appears to increase the risk of heart disease, blood clots, and
strokes. On the other hand it does lower the risk of colorectal cancer
and osteoporosis. We do have ways to prevent and treat osteoporosis and
regular colonoscopy screening is the best defense against colorectal cancer.
And although estrogen therapy does not seem to increase breast cancer
risk, it does increase the risk of stroke.
A decision to use hormone therapy should be made by a woman and her physician
after discussing the severity of symptoms from menopause and the possible
risks and benefits of therapy. Her other risk factors for heart disease,
breast cancer, and osteoporosis should be considered as well. If a decision
is made to try hormone therapy for symptoms of menopause, it is usually
best to use it at the lowest dose that works for her and for as short
a time as possible.
There are some studies that suggest breast-feeding may slightly lower breast
cancer risk, especially if it is continued for 1½ to 2 years. This
has been a difficult area to study, especially in countries such as the
United States, where breast-feeding for this long is uncommon.
The explanation for this possible effect may be that breast-feeding reduces
a woman's total number of lifetime menstrual cycles.
Alcohol consumption is clearly linked to an increased risk of developing
breast cancer and the risk increases with the amount of alcohol consumed.
When compared to non-drinkers, women who consume 1 alcoholic drink a day
have a very small increase in risk. Women who have 2 to 5 drinks daily
increase their risk about 1½ times the risk of women who drink
no alcohol. Excessive alcohol use is also known to increase the risk of
developing many other cancers including: mouth, throat, esophagus, and
liver. Recommendations are that women have no more than 1 alcoholic drink a day.
Being Overweight or Obese
Being overweight or obese has been found to increase breast cancer risk,
especially for post menopausal women. Before menopause your ovaries produce
most of your estrogen, and fat tissue produces a small amount of estrogen.
When the ovaries stop producing estrogen (after menopause), most of a
woman's estrogen comes from fat tissue. By having more fat tissue
after menopause your chance of getting breast cancer may be increased
because of raised estrogen levels. Women who are overweight also tend
to have higher blood insulin levels which have been linked to some cancers,
including breast cancer.
The connection between weight and breast cancer risk is complex, risk appears
to be increased for women who gained weight as an adult but may not be
increased among those who have been overweight since childhood. Excess
fat in the waist area may affect risk more than the same amount of fat
in the hips and thighs. Researchers believe that fat cells in various
parts of the body have subtle differences that may explain this.
It is important maintain a healthy weight throughout your life by balancing
your food intake with physical activity and avoiding excessive weight gain.
There is growing evidence that physical activity in the form of exercise
reduces breast cancer risk. The debate is how much exercise is needed.
A study from the Women's Health Initiative recommends as little as
1¼ to 2½ hours per week of brisk walking can reduce a woman's
risk by 18%. Walking 10 hours a week further reduced the risk. Current
recommendations support 30 to 60 minutes of physical activity at least
five days a week.