Breast Cancer Screening

What is Breast Cancer?

Breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast.

Facts and Figures

In Missouri, breast cancer has the fourth highest incidence and mortality rate among cancers.  Women in Missouri get breast cancer more than any other type of cancer except for skin cancer.

Breast cancer is more likely to occur as a woman ages. It occurs more often in white women than in black women, but black women die from breast cancer more often than white women.

Breast cancer rarely occurs in men. Because men with breast cancer usually have a lump that can be felt, screening tests are not likely to be helpful.

Screening Recommendation

The United States Preventive Services Task Force recommends that women aged 50 - 74 be screened for breast cancer using screening mammography every 2 years. 

Women who are 40 to 49 years old should talk to their doctor or other health care professional about when to start and how often to get a mammogram. Women should weigh the benefits and risks of screening tests when deciding whether to begin getting mammograms before the age of 50.

Screening Tests

Breast cancer screening means checking a woman’s breasts for cancer before there are signs or symptoms of the disease. Although breast cancer screening cannot prevent breast cancer, it can help find breast cancer early, when it is easier to treat. 

There are three kinds of exams that are used to screen for breast cancer. These include mammogram, breast MRI, clinical breast exam and breast self-exam.


A mammogram is an x-ray picture of the breast. Doctors use a mammogram to look for early signs of breast cancer. Regular mammograms are the best tests doctors have to find breast cancer early – sometimes up to three years before it can be felt.

A mammogram uses a machine designed to look only at breast tissue. The machine takes x-rays at lower doses than usual x-rays. Because these x-rays do not go through tissue easily, the machine has two plates that compress or flatten the breast to spread the tissue apart. This gives a better picture and allows less radiation to be used.

Mammograms are the best way to find breast cancer early, when it is easier to treat and before it is big enough to feel or cause symptoms. Having regular mammograms can lower the risk of dying from breast cancer.

Breast MRI

A breast MRI, or magnetic resonance imaging, uses magnets and radio waves to take pictures of the breast. MRI is used along with mammograms to screen women who are at higher risk for getting breast cancer. Because breast MRIs may appear abnormal even when there is no cancer, they are not used for women at average risk.  Women at high risk of breast cancer have a strong family history of the disease or have inherited BRCA1 or BRCA2 genes.

Whole Breast Ultrasound

Whole breast screening ultrasound is an exam used with mammograms to take a more complete look at women who have dense breast tissue. Ultrasound uses sound waves to take pictures of the breast. Women with dense breast tissue are at a higher risk of developing cancer compared to women with scattered density. Not only is dense breast a risk factor for developing cancer, it also makes cancer much harder to detect on a mammogram. Ultrasound can look through dense tissue that might otherwise hide a cancer. When mammogram and whole breast screening ultrasound are used together, doctors are able to detect 2-4 more cancers per thousand women screened.

Clinical Breast Exam

A clinical breast exam is a physical exam done by a health care provider. It is often done during a woman’s regular medical check-up.  Not all health care providers are trained to perform this type of exam, so clinical breast exams should only be performed by a health care provider who is trained in the technique.

During a clinical breast exam a trained provider carefully feels a patient’s breasts, underarm and the area just below the clavicle, or the breast bone, for any changes or abnormalities, such as a lump.

The provider will visually check a patient’s breasts while the patient is sitting up and lying down.

Breast Self-Exam

Breast self-examination, or BSE, is a technique which allows an individual to examine his or her own breast tissue for any physical or visual changes.

Breast self-examination is an important way for women as well as men to become familiar with the way their breasts normally look and feel.  This may help a person to notice a change in their breasts that should then be reported to a health care provider for follow-up.

Breast Cancer Screening Resources

Women who are concerned about the cost of receiving a screening mammogram or Pap test from their health care provider may have resources available to them to assist with covering this expense: Medicare Part B and Missouri’s Show Me Healthy Women program offer free breast and cervical cancer screenings for women who qualify.

Medicare Part B

Medicare is the federal health insurance program for people who are 65 or older; for certain younger people with disabilities; and for people with End-Stage Renal Disease, which is permanent kidney failure requiring dialysis or transplant.
Medicare Part B will cover 100% of the cost of a Pap test, a pelvic exam, and a breast exam for eligible participants once every 24 months.

Participants may be eligible for these screenings every 12 months if found to be at high risk for cervical cancer or are of childbearing age and have had an abnormal Pap test in the past 36 months.

Show Me Healthy Women

The Show Me Healthy Women program offers free breast and cervical cancer screenings for Missouri women who meet certain eligibility requirements.  Women who have an income at or below 200 percent of the federal poverty level for household income; are aged 35 to 64 or older; do not receive Medicare Part B; and do not have insurance to cover program services qualify for Show Me Healthy Women program benefits.

To locate a participating health care provider, visit Show Me Healthy Women or call 866-726-9926.

Breast Cancer Prevention

Breast cancer prevention involves avoiding risk factors that are known to increase the chance of developing breast cancer, as well as implementing actions that have been found to decrease breast cancer risk.  Some risk factors cannot be controlled, such as age, gender, race or family history.  However, there are some actions that can be taken to reduce breast cancer risk.

Limit Alcohol Consumption

Drinking alcohol increases the risk of breast cancer.  The level of risk increases as the amount of alcohol consumption rises.

Drinking alcohol also contributes to higher breast density in women.  Women with very dense breasts have a higher risk of breast cancer than women with low breast density.

Increased breast density is often an inherited trait, but it may also occur in women who have not had children, have a first pregnancy late in life, take postmenopausal hormones, or drink alcohol.

Increase Physical Activity

Women who exercise four or more hours a week have a lower risk of breast cancer. The effect of exercise on breast cancer risk may be greatest in premenopausal women who have normal or low body weight.

Maintain a Healthy Weight

Obesity increases the risk of breast cancer, especially in postmenopausal women who have not used hormone replacement therapy. Maintaining a healthy weight, which includes such activities as increasing physical activity; eating heathy foods like fruits, vegetables, whole grains; and balancing the number of calories consumed with the number of calories used can reduce breast cancer risk.

Reduce Exposure of Breast Tissue to Estrogen

Decreasing the length of time a woman's breast tissue is exposed to estrogen may help prevent breast cancer. Exposure to estrogen is reduced in the following ways:

  • Early pregnancy: Estrogen levels are lower during pregnancy.  Women who have a full-term pregnancy before age 20 have a lower risk of breast cancer than women who have not had children or who give birth to their first child after age 35.
  • Breastfeeding: Estrogen levels may remain lower while a woman is breastfeeding.  Women who breastfed have a lower risk of breast cancer than women who have had children but did not breastfeed.

Family History

Women with a family history of breast cancer in a first-degree relative (mother, sister, or daughter) have an increased risk of breast cancer. 

Women who are found to have a higher risk of breast cancer due to family health history may be recommended by a doctor for earlier mammography screening.  If the affected relative was diagnosed before age 50, had ovarian cancer or was a male relative with breast cancer, a doctor may give a referral for cancer genetic counseling.

Women who have inherited changes in the BRCA1 and BRCA2 genes or in certain other genes also have a higher risk of breast cancer. The risk of breast cancer caused by inherited gene changes depends on the type of gene mutation, family history of cancer, and other factors.


There are ways to reduce breast cancer risk in women that are found to be high risk for developing breast cancer.

Risk-Reducing Mastectomy

Some women who have a high risk of breast cancer may choose to have a risk-reducing mastectomy (the removal of both breasts when there are no signs of cancer). The risk of breast cancer is much lower in these women and most feel less anxious about the risk of breast cancer. However, it is very important to have a cancer risk assessment and counseling about the different ways to prevent breast cancer before making this decision.

Ovarian Ablation

The ovaries make most of the estrogen that is made by the body. Treatments that stop or lower the amount of estrogen made by the ovaries include surgery to remove the ovaries, radiation therapy, or taking certain drugs. This is called ovarian ablation.

Premenopausal women who have a high risk of breast cancer due to certain changes in the BRCA1 and BRCA2 genes may choose to have a risk-reducing oophorectomy (the removal of both ovaries when there are no signs of cancer). This decreases the amount of estrogen made by the body and lowers the risk of breast cancer. Risk-reducing oophorectomy also lowers the risk of breast cancer in normal premenopausal women and in women with an increased risk of breast cancer due to radiation to the chest. However, it is very important to have a cancer risk assessment and counseling before making this decision.

The sudden drop in estrogen levels may cause the symptoms of menopause to begin. These include hot flashes, trouble sleeping, anxiety, and depression. This procedure can also have long-term effects including decreased sex drive, vaginal dryness, and decreased bone density.

Selective Estrogen Receptor Modulators

Tamoxifen and raloxifene belong to the family of drugs called selective estrogen receptor modulators (SERMs). SERMs act like estrogen on some tissues in the body, but block the effect of estrogen on other tissues.

Treatment with tamoxifen lowers the risk of estrogen receptor-positive (ER-positive) breast cancer and ductal carcinoma in situ in premenopausal and postmenopausal women at high risk. Treatment with raloxifene also lowers the risk of breast cancer in postmenopausal women. With either drug, the reduced risk lasts for several years or longer after treatment is stopped. Lower rates of broken bones have been noted in patients taking raloxifene.

Taking tamoxifen increases the risk of hot flashes, endometrial cancer, stroke, cataracts, and blood clots (especially in the lungs and legs). The risk of having these problems increases in women older than 50 compared with younger women. Women younger than 50 who have a high risk of breast cancer may benefit the most from taking tamoxifen. The risk of having these problems decreases after tamoxifen is stopped.

Taking raloxifene increases the risk of blood clots in the lungs and legs, but does not appear to increase the risk of endometrial cancer. In postmenopausal women with osteoporosis (decreased bone density), raloxifene lowers the risk of breast cancer for women who have a high or low risk of breast cancer. It is not known if raloxifene would have the same effect in women who do not have osteoporosis.

Women with a high risk of breast cancer should speak with a doctor about the risks and benefits of taking these drugs to prevent breast cancer.

Aromatase Inhibitors and Inactivators

Aromatase inhibitors (anastrozole, letrozole) and inactivators (exemestane) lower the risk of recurrence and of new breast cancers in women who have a history of breast cancer.

Aromatase inhibitors also decrease the risk of breast cancer in women with the following conditions:

  • postmenopausal women with a personal history of breast cancer;
  • women with no personal history of breast cancer who are 60 years and older;
  • have a history of ductal carcinoma in situ with mastectomy; or
  • have a high risk of breast cancer based on the Gail model tool (a tool used to estimate the risk of breast cancer).

In women with an increased risk of breast cancer, taking aromatase inhibitors decreases the amount of estrogen made by the body. Before menopause, estrogen is made by the ovaries and other tissues in a woman's body, including the brain, fat tissue, and skin. After menopause, the ovaries stop making estrogen, but the other tissues do not. Aromatase inhibitors block the action of an enzyme called aromatase, which is used to make all of the body's estrogen. Aromatase inactivators stop the enzyme from working.

Possible harms from taking aromatase inhibitors include muscle and joint pain, osteoporosis, hot flashes, and feeling very tired.

Estrogen-Only Hormone Therapy

Hormones, such as estrogen and progesterone, can be made into a pill form in a laboratory. Estrogen, progestin, or both may be given to replace the estrogen no longer made by the ovaries in postmenopausal women or women who have had their ovaries removed. This is called hormone replacement therapy (HRT) or hormone therapy (HT). Combination HRT/HT is estrogen combined with progestin. This type of HRT/HT increases the risk of breast cancer. Studies show that when women stop taking estrogen combined with progestin, the risk of breast cancer decreases.

Hormone therapy with estrogen only may be given to women who have had a hysterectomy. In these women, estrogen-only therapy after menopause may decrease the risk of breast cancer. There is an increased risk of stroke and heart and blood vessel disease in postmenopausal women who take estrogen after a hysterectomy.

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