Breast Cancer Risk Factors
Early onset of menses and late menopause: Onset of the menstrual
cycle prior to the age of 12 and menopause after 50 causes increased
risk of developing breast cancer.
Diets high in saturated fat: The types of fat are important. Monounsaturated
fats such as canola oil and olive oil do not appear to increase
the risk of developing breast cancer like polyunsaturated fats;
corn oil and meat.
Family history of breast cancer: Patients with a positive family
history of breast cancer are at increased risk for developing the
disease. However, 85% of women with breast cancer have a negative
family history!
Family history only includes immediate relatives, mother, sisters
and daughters. If a family member was post-menopausal (fifty or
older) when she was diagnosed with breast cancer, the lifetime risk
is only increased 5%. If the family member was premenopausal, the
lifetime risk is 18.6%. If the family member was premenopausal and
had bilateral breast cancer, the lifetime risk is 50%.
Genetic testing of the BRCA1 and BRCA2 genes is increasingly being
integrated into clinical care for appropriately counseled adults
who meet established criteria for this testing. The American Society
of Clinical Oncologists (ASCO) and the National Comprehensive Cancer
Network (NCCN) are among the professional healthcare organizations
who have published criteria for genetic counseling/testing and cancer
risk management. Increased and earlier surveillance, chemoprevention
(tamoxifen, oral contraceptives) and surgical interventions (mastectomy,
oophorectomy - removal of the ovaries and fallopian tubes) are among
the current early detection and risk-reducing strategies discussed
with women undergoing BRCA testing. In contrast to breast cancer,
there is no reliable early detection for ovarian cancer, which is
often fatal due to late stage at diagnosis. Therefore, oophorectomy
is generally recommended between ages 35-40 or upon completion of
childbearing for women at high risk for ovarian cancer. Despite
initial concerns about insurance coverage discrimination, many insurers,
including major indemnity plans (BC/BS, Aetna, Kaiser, etc.) recognize
the healthcare benefits of this BRCA testing and cover test and
genetic counsultation fees when demmed medically necessary. To date,
more than 10,000 women and men have had BRCA testing. Similar to
other medical tests, BRCA test results are often used to substantiate
the need for the early detection and risk-reducing options available
for individuals at high-risk for breast and ovarian cancers.
Late or no pregnancies: Pregnancies prior to the age of twenty-six
are somewhat protective. Nuns have a higher incidence of breast
cancer.
Moderate alcohol intake: Greater than two alcoholic beverages per
day.
Estrogen replacement therapy: Most studies indicate that taking
estrogen longer than ten years may lead to a slight increase in
risk for developing breast cancer. However, these studies indicate
that the positive benefits of taking estrogen as far as reducing
the risk for osteoporosis, heart disease and now more recently Alzheimer's
and colon cancer, far outweigh the slight increase in risk that
may be associated with estrogen replacement therapy.
Caution should be exercised in those women with a significantly
positive family history of breast cancer or atypical intraductal
hyperplasia. Women with breast cancer are not currently give estrogen
replacement. There are no scientific studies currently justifying
this practice. However, until those studies are available, by convention,
women are taken off estrogen.
History of prior breast cancer: Patients with a prior history of
breast cancer are at increased risk for developing breast cancer
in the other breast. This risk is 1% per year or a lifetime risk
of 10%. The reason for close clinical follow-up after the diagnosis
of breast cancer is not only to detect recurrence of the disease,
but also to detect breast cancer in the opposite breast.
Female: The mere fact that being female increases the risk of developing
breast cancer. However, for every 100 women with breast cancer,
1 male will develop the disease.
Therapeutic irradiation to chest wall i.e., for Hodgkins Disease
(cancer of lymph nodes): Patients who have had therapeutic irradiation
to the chest are at increased risk for developing breast cancer
approximately 10 years later and consideration should be given to
earlier screening in this population.
Moderate obesity: The relationship of breast cancer to obesity
is more complex but associated with an increased risk.
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