Abnormalities or Breast
Conditions Suggesting a Higher Risk. Some breast formations
or abnormalities should be watched and include the
Dense breast tissue is
associated with a higher risk for breast cancer. Studies
suggest that in women with highly dense tissue have two to
six times the risk of women with the least dense tissue.
Genetic factors play a large role in breast density. Hormone
replacement therapy also increases breast density.
Benign proliferative breast
disease or atypical cell growth, known as atypical
hyperplasia, is a significant risk factor for breast cancer.
Benign Breast Conditions.
Benign breast conditions are much more commonly seen on
mammograms than cancer. And in the great majority of cases
they pose no risk. Some common benign breast abnormalities
that pose few or no risks include the following:
These mostly occur in women in their middle to late
reproductive years and can be eliminated simply by
aspirating fluid from them.
following physical characteristics have been associated with
increases the risk for all types of estrogen
receptor-positive breast cancers. Women who gain weight
after menopause are most at risk. (On a positive note,
losing weight after menopause decreases breast cancer risk.)
In postmenopausal women, estrogen is produced in fat tissue.
High amounts of fatty tissue increase levels of estrogen in
the body, leading to faster growth of estrogen-sensitive
involved in building bone mass. Therefore, women with heavy,
dense bones are likely to have higher estrogen levels and to
be at greater risk for breast cancer.
studies have found a greater risk for breast cancer in
taller women, possibly due to the higher estrogen levels
associated with greater bone growth. In one study,
regardless of their actual height, women who reached their
full height at age 13 or younger had a higher risk than
those who attained maximum height at age 18, reflecting
higher estrogen levels at an earlier age.
Estrogen-like Industrial Chemicals. Chemicals with
estrogen-like effects, called xenoestrogens, have been under
suspicion for years. There has been particular concern with
pesticides containing organochlorines (DDT and its
metabolites, such as dieldrin) and pyrethroids (permethrin),
but at this time evidence of any causal association is very
Exposure to Diethylstilbestrol
(DES). Women who took diethylstilbestrol (DES) to prevent
miscarriage have a slightly increased risk for breast
cancer. To date, this risk has not been seen in their
daughters (commonly called "DES daughters"), who were
exposed to the drug when their mothers took it during
Radiation Exposure. Heavy
exposure to radiation is a significant risk factor for
breast cancer. Children receiving high-dose radiation
therapy face an increased risk for breast cancer in
adulthood. Low-dose radiation exposure before age 20 may
increase the risk for women with BRCA genetic mutations.
Researchers theorize that
viruses may be involved in some types of breast cancers. A
study of breast cancer samples taken from Tunisian women in
North Africa found similarities with a virus known to cause
breast cancer in mice. The samples were compared with those
taken from women living in other global regions. The
researchers suggested that a human breast cancer virus may
be more prevalent in specific parts of the world.
Insulin-Like Growth Factor
Insulin-like growth factor 1
is an important growth hormone during development in the
womb and childhood. It has powerful properties that increase
cell proliferation, and high concentrations have now been
linked to cancers, including premenopausal breast cancer. In
fact, it may be one of the factors that are responsible for
the association between height and breast cancer. More
research is needed to verify a possible role of insulin-like
growth factor 1 in breast cancer development.
Prevention and Lifestyle
Several studies suggest that
regular exercise, particularly vigorous exercise, may offer
some modest protection against breast cancer. Exercise can
help reduce body fat, which in turn lowers levels of
cancer-promoting hormones such as estrogen. Exercise can
also help women who have been diagnosed with breast cancer.
Studies indicate that both aerobic and weight training
exercises benefit the body and the mind, and improve quality
of life for breast cancer survivors. Even moderate exercise
can help improve survival. A 2005 study in the Journal of
the American Medical Association reported survival benefits
for women diagnosed with breast cancer who walked 3 – 5
hours per week at an average pace.
Much research has targeted the
role of diet in breast cancer, either as a risk factor or as
a factor for patients already diagnosed with cancer.
Fats: Although some studies
have found an association between high-fat intake and breast
cancer, the most recent data suggest that fat from any
source (vegetable oils or animal products) plays an
insignificant role in increasing the risk for breast cancer.
According to some studies, monounsaturated fats (found in
olive, peanut, and canola oils) may even be protective.
Vitamins and Chemicals in
Fruits and Vegetables. Many fresh fruits and vegetables
contain chemicals that may be cancer fighters. Experts are
investigating whether any specific vitamins, nutrients, or
teams of them may be specifically valuable.
enzymes that convert estrogen to a more benign form and may
block steroid hormones that promote breast and prostate
cancers. They are found in broccoli, cabbage, Brussels
sprouts, cauliflower, collards, kale, kohlrabi, mustard
greens, rutabaga, turnips, and bok choy.
Polyphenols, found in apples, onions, and green tea, may
be beneficial, although this is controversial.
(Chemicals in green tea in particular have been studied
for cancer-fighting effects in breast cancer.)
Lycopene, found in tomatoes may have cancer-fighting
is some evidence that foods containing folate (folic
acid) may be protective. It is found in avocado,
bananas, orange juice, asparagus, fruits, green leafy
vegetables, dried beans and peas, and yeast. It is also
added to commercial grain products.
- Foods high in vitamin
C have also been associated with a lower risk (although
there is not evidence of protection from any vitamin
supplements, including C or E).
Dairy Products and Other
Protein Foods. Studies suggest that dairy products may also
play a protective role in premenopausal women. If this is
eventually verified, it is not clear if protection comes
from calcium and vitamin D in these foods or if there are
others factors involved. Women who increase their intake
should choose low- or no-fat dairy products.
One study reported that women
with breast cancer who had a high intake of protein from
both poultry and dairy products had a better outlook than
those with a lower intake of these foods. In this study, red
meat appeared to have no effect one way or the other. Other
studies, however, have found a higher risk of breast cancer
in women who consume higher quantities of flame-broiled
meats, particularly women who are sensitive to chemicals
released during the process. Fish may offer some protection.
Iron. Animal studies have
linked a higher incidence of breast cancer with iron-rich
diets, and in humans, high iron stores have been associated
with a higher risk for breast cancer. Estrogen appears to
increase iron levels in cells, and iron produces oxidants
(damaging particles) that are associated with cancer. More
research is needed to confirm these findings, however.
Soy and Phytoestrogens
estrogen-like substances found in plant products. These
include soybeans, black cohosh (an herb), whole wheat,
berries, and flaxseed. In general, the evidence on their
effects on breast cancer is unclear.
Most research has focused on
soy. In general, Asian women have a lower incidence of
reproductive and breast cancers as well as a higher intake
of soy. For example, a 2000 Asian study reported an
association between high levels of soy compounds in the
urine and a significantly lower risk for breast cancer. A
2001 study in China reported that high soy intake during
adolescence was associated with a lower risk for breast
cancer later on.
The effects of phytoestrogens,
however, in all cases are far from settled. Of concern are
studies that report breast cell proliferation with low
levels of genistein (one of the important isoflavones
compounds in soy). In one study, the compound actually
reversed the protective properties of tamoxifen, a drug used
to prevent breast cancer in high-risk women. In general,
women at risk for breast cancer, especially women who take
hormone replacement therapy, should avoid consuming large
amounts of plant products with high levels of phytoestrogens
until more is known about their effects.
Several studies have reported
a higher risk for breast cancer in women who consume
alcohol. A well-conducted 2003 analysis of many of these
studies suggested that for every daily drink there was a 7%
increase in breast cancer. By age 80, women who consumed two
drinks a day had a 10% increased risk for developing breast
cancer. Based on these findings, researchers suggested that
about 4% of breast cancer cases in developed nations may be
attributed to alcohol. (Women who drink and who take hormone
replacement therapy have an even greater risk.) Some
research indicates that alcohol in such amounts increases
levels of growth factors that can stimulate breast cancer
cells. However, light to moderate drinking has benefits for
the heart that most likely outweigh the cancer risk in most
women who have no other risk factors for breast cancer or
Several studies have reported
that breastfeeding is associated with a lower risk for
cancer in premenopausal women. Some studies also suggest
that some protective effect from breastfeeding may last
beyond menopause. Studies also indicate that the longer the
mother breastfeeds, the better. In fact, some experts
believe the high rates of breast cancer in developed
countries may be partly due to a lack of or shorter duration