Causes
of Breast Cancer
Following
are the causes of Breast Cancer may
be there other causes which are not mentioned
here.
Gender: Simply being a woman is the main risk for breast cancer. While
men can also get the disease, it is about 100 times more common in women than in
men.
Age: The chance of getting breast cancer goes up as a woman gets
older. Nearly 8 out of 10 breast cancers are found in women over age 50.
Genetic risk factors: About 5% to 10% of breast cancers are linked to
changes (mutations) in certain genes. The most common gene changes are those of
the BRCA1 and BRCA2 genes. Women with these gene changes have up to an 80%
chance of getting breast cancer during their lifetimes. Other gene changes may
raise breast cancer risk as well.
Family history: Breast cancer risk is higher among women whose close
blood relatives have this disease. The relatives can be from either the
motherÂ’s or fatherÂ’s side of the family. Having a mother, sister, or daughter
with breast cancer about doubles a womanÂ’s risk.
Personal history of breast cancer: A woman with cancer in one breast
has a greater chance of getting a new cancer in the other breast or in another
part of the same breast. This is different from the first cancer coming back
(recurrence).
Race: White women are slightly more likely to get breast cancer than
are African-American women. But African American women are more likely to die of
this cancer. Many experts now believe that the main reason for this is because
they have faster growing tumors. Asian, Hispanic, and American Indian women have
a lower risk of getting breast cancer.
Earlier abnormal breast biopsy: Certain types of abnormal biopsy
results can be linked to a slightly higher risk of breast cancer.
Earlier breast radiation: Women who have had radiation treatment to
the chest area earlier in life have a greatly increased risk of breast cancer.
Menstrual periods: Women who began having periods early (before 12
years of age) or who went through the change of life (menopause) after the age
of 55 have a slightly increased risk of breast cancer.
Treatment with DES: In the past, some pregnant women were given the
drug DES (diethylstilbestrol) because it was thought to lower their chances of
losing the baby. Recent studies have shown that these women have a slightly
increased risk of getting breast cancer.
Breast Cancer Risk and Lifestyles
Not having children: Women who have had not had children, or who had
their first child after age 30, have a slightly higher risk of breast cancer.
Being pregnant more than once and at an early age reduces breast cancer risk.
Birth control pills: It is still not clear what part birth control
pills might play in breast cancer risk. Studies have found that women now using
birth control pills have a slightly greater risk of breast cancer. Women who
stopped using the pill more than 10 years ago do not seem to have any increased
risk. ItÂ’s a good idea to discuss the risks and benefits of birth control pills
with your doctor.
Hormone replacement therapy (HRT): It has become clear that long-term
use (several years or more) of combined HRT (estrogens together with
progesterone) after menopause increases the risk of breast cancer as well as the
risk of heart disease, blood clots, and strokes. The breast cancers are also
found at a more advanced stage, perhaps because HRT seems to reduce the
effectiveness of mammograms. Five years after stopping HRT, the breast cancer
risk appears to drop back to normal. Estrogen alone (ERT) does not seem to
increase the risk of breast cancer as much, if at all.
At this time, there appear to be few strong reasons to use HRT, other than
for short-term relief of menopausal symptoms. Because there are other factors to
think about, you should talk with your doctor about the pros and cons of using
HRT.
Breast-feeding and pregnancy: Some studies have shown that
breast-feeding slightly lowers breast cancer risk, especially if the
breast-feeding lasts 1½ to 2 years. This could be because breast-feeding lowers
a womanÂ’s total number of menstrual periods, as does pregnancy. One study found
that having more children and breast-feeding longer could reduce the risk of
breast cancer by half.
Alcohol: Use of alcohol is clearly linked to a slightly increased risk
of getting breast cancer. Women who have 1 drink a day have a very small
increased risk. Those who have 2 to 5 drinks daily have about 1½ times the risk
of women who drink no alcohol. The ACS suggests limiting the amount you drink.
Diet: Being overweight is linked to a higher risk of breast cancer,
especially for women after change of life and if the weight gain took place
during adulthood. Also, the risk seems to be higher if the extra fat is in the
waist area. But the link between weight and breast cancer risk is complex, and
studies of fat in the diet as it relates to breast cancer risk have often given
conflicting results.
Since diet and weight have been shown to affect the risk of getting several
other types of cancer as well as heart disease, the ACS says itÂ’s best to stay
at a healthy weight and limit your use of red meats, especially those high in
fat or processed.
Exercise: Studies show that exercise reduces breast cancer risk. The
only question is how much exercise is needed. One study found that as little as
1 hour and 15 minutes to 2 and a half hours per week of brisk walking reduced
the risk by 18%. Walking 10 hours a week reduced the risk a little more.
Uncertain Risk Factors
A lot of research is being done to learn how the environment might affect
breast cancer risk. At this time, research does not show a clear link between
breast cancer risk and environmental pollutants, such as pesticides and PCBs.
While a direct link between smoking and breast cancer has not been found,
some studies suggest it might increase breast cancer risk, particularly for
women who start smoking as teens. Smoking affects your overall health and
increases the risk for many other cancers, as well as heart disease. If you
smoke, you should make every attempt to quit.
Internet e-mail rumors have suggested that underarm antiperspirants can cause
breast cancer. There is very little evidence to support this idea. Also, there
is no evidence to support the idea that underwire bras cause breast cancer.
Several studies show that induced abortions do not increase the risk of
breast cancer. Also, there is no evidence to show a direct link between
miscarriages and breast cancer.
Silicone breast implants can cause scar tissue to form in the breast. But
several studies have found that this does not increase breast cancer risk. If
you have breast implants, you might need a special x-ray picture during
mammography.
A few recent studies have suggested that women who work at night (nurses on
the night shift, for example) have a higher risk of breast cancer. But this has
not yet been proven. Also, a recent study suggested women who took antibiotics
may have a slightly higher risk of breast cancer. This link is also not clear
yet.
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