What is breast cancer?


Breast cancer is a disease in which certain cells in the breast become abnormal and multiply uncontrollably to form a tumor. Although breast cancer is much more common in women, this form of cancer can also develop in men. In both women and men, the most common form of breast cancer begins in cells lining the milk ducts (ductal cancer). In women, cancer can also develop in the glands that produce milk (lobular cancer). Most men have little or no lobular tissue, so lobular cancer in men is very rare.

In its early stages, breast cancer usually does not cause pain and may exhibit no noticeable symptoms. As the cancer progresses, signs and symptoms can include a lump or thickening in or near the breast; a change in the size or shape of the breast; nipple discharge, tenderness, or retraction (turning inward); and skin irritation, dimpling, or scaliness. However, these changes can occur as part of many different conditions. Having one or more of these symptoms does not mean that a person definitely has breast cancer.

In some cases, cancerous tumors can invade surrounding tissue and spread to other parts of the body. If breast cancer spreads, cancerous cells most often appear in the bones, liver, lungs, or brain. Tumors that begin at one site and then spread to other areas of the body are called metastatic cancers.

A small percentage of all breast cancers cluster in families. These cancers are described as hereditary and are associated with inherited gene mutations. Hereditary breast cancers tend to develop earlier in life than non-inherited (sporadic) cases, and new (primary) tumors are more likely to develop in both breasts.

How common is breast cancer?


Breast cancer is the second most commonly diagnosed cancer in women. (Only skin cancer is more common.) About one in eight women in the United States will develop invasive breast cancer in her lifetime. Researchers estimate that more than 230,000 new cases of invasive breast cancer will be diagnosed in U.S. women in 2015.

Male breast cancer represents less than 1 percent of all breast cancer diagnoses. Scientists estimate that about 2,300 new cases of breast cancer will be diagnosed in men in 2015.

Particular gene mutations associated with breast cancer are more common among certain geographic or ethnic groups, such as people of Ashkenazi (central or eastern European) Jewish heritage and people of Norwegian, Icelandic, or Dutch ancestry.

BRCA Risk Chart
BRCA Risk Chart

What are the risk factors for breast cancer?

 

Risk factors you cannot change



Gender
Simply being a woman is the main risk factor for developing breast cancer. Men can develop breast cancer, but it’s about 100 times more common among women than men. This is probably because men have less breast tissue, as well as less of the female hormones estrogen and progesterone, which can promote breast cancer cell growth.

Aging
Your risk of developing breast cancer goes up as you get older. About 1 out of 8 invasive breast cancers are found in women younger than 45, while about 2 of 3 invasive breast cancers are found in women age 55 or older.

Inheriting certain genes
About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they are caused by gene defects (called mutations) passed on from a parent.

BRCA1 and BRCA2 gene changes
The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 or BRCA2 gene. In normal cells, these genes help prevent cancer by making proteins that help keep the cells from growing out of control. If you inherited a mutated copy of either gene from a parent, you have a high risk of developing breast cancer during your lifetime.

Although in some families with BRCA1 mutations the lifetime risk of breast cancer is as high as 80%, on average this risk seems to be in the range of 55 to 65%. For BRCA2 mutations the risk is lower, around 45%.

Breast cancers linked to these mutations occur more often in younger women and more often affect both breasts than cancers not linked to these mutations. Women with these inherited mutations also have an increased risk for developing other cancers, particularly ovarian cancer.

In the United States, BRCA mutations are more common in Jewish people of Ashkenazi (Eastern Europe) origin than in other racial and ethnic groups, but they can occur in anyone.

Changes in other genes: Other inherited gene mutations can also lead to breast cancer. These gene mutations are much less common and often do not increase the risk of breast cancer as much as the BRCA genes.

  1. ATM: The ATM gene makes a protein that normally helps repair damaged DNA. Inheriting 2 abnormal copies of this gene (one from each parent) causes the disease ataxia-telangiectasia. Inheriting one abnormal copy of this gene has been linked to a high rate of breast cancer in some families.

  2. TP53: The TP53 gene makes a protein called p53 that helps stop the growth of abnormal cells. Inherited mutations of this gene cause Li-Fraumeni syndrome. People with this syndrome have an increased risk of breast cancer, as well as other cancers such as leukemia, brain tumors, and sarcomas (cancers of bones or connective tissue). This is a rare cause of breast cancer.

  3. CHEK2: The Li-Fraumeni syndrome can also be caused by inherited mutations in the CHEK2 gene. Even when it doesn’t cause this syndrome, it can increase breast cancer risk when it’s mutated.

  4. PTEN: The PTEN gene normally helps regulate cell growth. Inherited mutations in this gene cause Cowden syndrome, a rare disorder in which people are at increased risk for both benign and malignant breast tumors, as well as growths in the digestive tract, thyroid, uterus, and ovaries. Defects in this gene can also cause a different syndrome called Bannayan-Riley-Ruvalcaba syndrome that’s not thought to be linked to breast cancer risk. The syndromes caused by mutations in PTEN can be grouped together as PTEN Tumor Hamartoma Syndrome.

  5. CDH1: Inherited mutations in this gene cause hereditary diffuse gastric cancer, a syndrome in which people develop a rare type of stomach cancer at an early age. Women with mutations in this gene also have an increased risk of invasive lobular breast cancer.

  6. STK11: Defects in this gene can lead to Peutz-Jeghers syndrome. People affected with this disorder develop pigmented spots on their lips and in their mouths, polyps in the urinary and gastrointestinal tracts, and have an increased risk of many types of cancer, including breast cancer.

  7. PALB2: The PALB2 gene makes a protein that interacts with the protein made by the BRCA2 gene. Defects in this gene can lead to an increased risk of breast cancer. It isn’t yet clear if PALB2 gene mutations also increase the risk for ovarian cancer and male breast cancer.


Genetic testing
Genetic testing can be done to look for mutations in the BRCA1 and BRCA2genes (or less commonly in other genes such as PTEN or TP53). Although testing can be helpful in some situations, the pros and cons need to be considered carefully. If you are thinking about genetic testing, it’s strongly recommended that first you talk to a genetic counselor, nurse, or doctor qualified to explain and interpret the results of these tests. It’s very important to understand what genetic testing can and can’t tell you, and to carefully weigh the benefits and risks of genetic testing before these tests are done. Testing is expensive and might not be covered by some health insurance plans.

For more information, you might also want to visit the National Cancer Institute website.

Elite Diagnostics provides testing of Common and Less Common gene mutations as outlined above, and can provide appropriate referrals to genetic counselors for you and your physician.

Family history of breast cancer
Breast cancer risk is higher among women whose close blood relatives have this disease. Having a first-degree relative (mother, sister, or daughter) with breast cancer about doubles a woman’s risk. Having 2 first-degree relatives increases her risk about 3-fold. Although the exact risk is not known, women with a family history of breast cancer in a father or brother also have an increased risk of breast cancer.

Overall, less than 15% of women with breast cancer have a family member with this disease. This means that most (85%) women who get breast cancer do not have a family history of this disease.

Personal history of breast cancer

A woman with 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 different from a recurrence (return) of the first cancer.) This risk is even higher if breast cancer was diagnosed at a younger age. Race and ethnicity

Overall, white women are slightly more likely to develop breast cancer than are African-American women, but African-American women are more likely to die of this cancer. In women under 45 years of age, however, breast cancer is more common in African-American women. Asian, Hispanic, and Native American women have a lower risk of developing and dying from breast cancer.

Dense breast tissue
Breasts are made up of fatty tissue, fibrous tissue, and glandular tissue. A woman is said to have dense breasts (on a mammogram) when she has more glandular and fibrous tissue and less fatty tissue. Women with dense breasts on a mammogram have a risk of breast cancer that is 1.2 to 2 times that of women with average breast density. Unfortunately, dense breast tissue can also make mammograms less accurate. A number of factors can affect breast density, such as age, menopausal status, the use of certain drugs (including menopausal hormone therapy), pregnancy, and genetics.

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. Doctors often divide benign breast conditions into 3 general groups, depending on how they affect this risk.

Non-proliferative lesions
These are not associated with overgrowth of breast tissue. They do not seem to affect breast cancer risk, or if they do, it’s to a very small extent. They include:

  • Fibrosis and/or simple cysts (sometimes called fibrocystic changes or disease)
  • Mild hyperplasia
  • Adenosis (non-sclerosing)
  • Phyllodes tumor (benign)
  • A single papilloma
  • Fat necrosis
  • Duct ectasia
  • Periductal fibrosis
  • Squamous and apocrine metaplasia
  • Epithelial-related calcifications
  • Other benign tumors (such as lipoma, hamartoma, hemangioma, neurofibroma, adenomyoepthelioma)

 

Mastitis (infection of the breast) is not a lesion, and it doesn’t increase the risk of breast cancer.

Proliferative lesions without atypia
These conditions show excessive growth of cells in the ducts or lobules of the breast tissue. They seem to raise a woman’s risk of breast cancer slightly (1½ to 2 times normal). They include:

  • Usual ductal hyperplasia (without atypia)
  • Fibroadenoma
  • Sclerosing adenosis
  • Several papillomas (called papillomatosis)
  • Radial scar


Proliferative lesions with atypia
In these conditions, there’s excessive growth of cells in the ducts or lobules of the breast tissue, and some of the cells do not look normal. These have a stronger effect on breast cancer risk, raising it about 4 to 5 times higher than normal. These types of lesions include:

  • 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
In lobular carcinoma in situ (LCIS), cells that look like cancer cells are growing in the lobules of the milk-producing glands of the breast, but they have not grown through the wall of the lobules. LCIS (also called lobular neoplasia) is sometimes grouped with ductal carcinoma in situ (DCIS) as a non-invasive breast cancer, but it differs from DCIS in that it doesn’t seem to become invasive cancer if it isn’t treated.

Women with LCIS have a 7- to 11-fold increased risk of developing cancer in either breast.

Starting menstruation before age 12
Women who have had more menstrual cycles (periods) because they started menstruating early (before age 12) 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.

Going through menopause after age 55
Women who have had more menstrual cycles because they went through menopause later (after age 55) 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
Women who as children or young adults were treated with radiation therapy to the chest area for another cancer (such as Hodgkin disease or non-Hodgkin lymphoma) have an increased breast cancer risk. This varies with the patient’s age when they got radiation. The risk 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
From the 1940s through the early 1970s some pregnant women were given DES, an estrogen-like drug, because it was thought to lower their chances of losing the baby (miscarriage). 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.

Risk factors you can change


Drinking alcohol
Drinking alcohol is clearly linked to an increased risk of breast cancer. The risk increases with the amount of alcohol consumed. Excessive alcohol consumption is also known to increase the risk of developing several other cancers.

Being overweight or obese
Being overweight or obese after menopause increases breast cancer risk. Before menopause your ovaries make most of your estrogen, and fat tissue makes a small amount. After menopause (when the ovaries stop making estrogen), most of a woman’s estrogen comes from fat tissue. Having more fat tissue after menopause can increase your chance of getting breast cancer by raising estrogen levels. Also, women who are overweight tend to have higher blood insulin levels. Higher insulin levels have also been linked to some cancers, including breast cancer.

The connection between weight and breast cancer risk is complex. For instance, risk appears to be increased for women who gained weight as an adult but may not be increased in those who have been overweight since childhood. Also, 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.

Physical activity
Evidence is growing that physical activity in the form of exercise reduces breast cancer risk. The main question is how much exercise is needed. In one study from the Women’s Health Initiative, as little as 1¼ to 2½ hours per week of brisk walking reduced a woman’s risk by 18%. Walking 10 hours a week reduced the risk a little more.

Having children
Women who have not had children or who had their first child after age 30 have a slightly higher breast cancer risk overall. Having many pregnancies and becoming pregnant at an early age reduces breast cancer risk overall. Still, the effect of pregnancy is different for different types of breast cancer.

Birth control
Oral contraceptives: Studies have found that women using oral contraceptives (birth control pills) have a slightly greater risk of breast cancer than women who have never used them. This risk seems to go back to normal over time once the pills are stopped. Women who stopped using oral contraceptives more than 10 years ago don’t appear to have any increased breast cancer risk.

Depot-medroxyprogesterone acetate (DMPA; Depo-Provera): This is an injectable form of progesterone that is given once every 3 months as birth control. A few studies have looked at the effect of DMPA on breast cancer risk. Women currently using DMPA seem to have an increase in risk, but the risk doesn’t seem to be increased if this drug was used more than 5 years ago.

Hormone therapy after menopause
Hormone therapy with estrogen (often combined with progesterone) has been used for many years to help relieve symptoms of menopause and to help prevent osteoporosis (thinning of the bones). This treatment goes by many names, such as post-menopausal hormone therapy(PHT), hormone replacement therapy (HRT), and menopausal hormone therapy (MHT).

There are 2 main types of hormone therapy:

For women who still have a uterus (womb), doctors generally prescribe estrogen and progesterone (known as combined hormone therapy or HT). Progesterone is needed because estrogen alone can increase the risk of cancer of the uterus.
For women who’ve had a hysterectomy (those who no longer have a uterus), estrogen alone can be prescribed. This is commonly known as estrogen replacement therapy(ERT) or just estrogen therapy (ET).

Combined hormone therapy (HT): Use of combined hormone therapy increases the risk of getting breast cancer. It may also increase the chances of dying from breast cancer.
Estrogen therapy (ET): The use of estrogen alone after menopause does not appear to increase the risk of developing breast cancer.

Breastfeeding
Some studies suggest that breastfeeding may slightly lower breast cancer risk, especially if it’s done for at least a year. But this has been hard to study, especially in countries like the United States, where breastfeeding for this long is uncommon.

The reason for this possible effect may be that breastfeeding reduces a woman’s total number of lifetime menstrual cycles (the same as starting menstrual periods at a later age or going through early menopause).

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How can a person who has a positive test result manage their risk of cancer?


Several options are available for managing cancer risk in individuals who have a known harmful BRCA1 or BRCA2 mutation. These include enhanced screening, prophylactic (risk-reducing) surgery, and chemoprevention.

Enhanced Screening. Some women who test positive for BRCA1 and BRCA2mutations may choose to start cancer screening at younger ages than the general population or to have more frequent screening. For example, some experts recommend that women who carry a harmful BRCA1 or BRCA2 mutation undergo clinical breast examinations beginning at age 25 to 35 years (19). And some expert groups recommend that women who carry such a mutation have a mammogram every year, beginning at age 25 to 35 years.

Enhanced screening may increase the chance of detecting breast cancer at an early stage, when it may have a better chance of being treated successfully. Women who have a positive test result should ask their health care provider about the possible harms of diagnostic tests that involve radiation (mammograms or x-rays).

Recent studies have shown that MRI may be more sensitive than mammography for women at high risk of breast cancer (20, 21). However, mammography can also identify some breast cancers that are not identified by MRI (22), and MRI may be less specific (i.e., lead to more false-positive results) than mammography. Several organizations, such as the American Cancer Society and the National Comprehensive Cancer Network, now recommend annual screening with mammography and MRI for women who have a high risk of breast cancer.

Women may choose to have both breasts removed (bilateral prophylactic mastectomy) to reduce their risk of breast cancer. Surgery to remove a woman's ovaries and fallopian tubes (bilateral prophylactic salpingo-oophorectomy) can help reduce her risk of ovarian cancer. Removing the ovaries also reduces the risk of breast cancer in premenopausal women by eliminating a source of hormones that can fuel the growth of some types of breast cancer.

No evidence is available regarding the effectiveness of bilateral prophylactic mastectomy in reducing breast cancer risk in men with a harmful BRCA1 or BRCA2 mutation or a family history of breast cancer. Therefore, bilateral prophylactic mastectomy for men at high risk of breast cancer is considered an experimental procedure, and insurance companies will not normally cover it.

Prophylactic surgery does not completely guarantee that cancer will not develop because not all at-risk tissue can be removed by these procedures. Some women have developed breast cancer, ovarian cancer, or primary peritoneal carcinomatosis (a type of cancer similar to ovarian cancer) even after prophylactic surgery. Nevertheless, the mortality reduction associated with this surgery is substantial: Research demonstrates that women who underwent bilateral prophylactic salpingo-oophorectomy had a nearly 80 percent reduction in risk of dying from ovarian cancer, a 56 percent reduction in risk of dying from breast cancer (24), and a 77 percent reduction in risk of dying from any cause (25).

Emerging evidence (25) suggests that the amount of protection that removing the ovaries and fallopian tubes provides against the development of breast and ovarian cancer may be similar for carriers of BRCA1 and BRCA2 mutations, in contrast to earlier studies (26).

Chemoprevention. Chemoprevention is the use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the recurrence of, cancer. Although two chemopreventive drugs (tamoxifen and raloxifene) have been approved by the U.S. Food and Drug Administration (FDA) to reduce the risk of breast cancer in women at increased risk, the role of these drugs in women with harmful BRCA1 or BRCA2 mutations is not yet clear.

Data from three studies suggest that tamoxifen may be able to help lower the risk of breast cancer in BRCA1 and BRCA2 mutation carriers (27), including the risk of cancer in the opposite breast among women previously diagnosed with breast cancer (28, 29). Studies have not examined the effectiveness of raloxifene in BRCA1 and BRCA2 mutation carriers specifically.

Oral contraceptives (birth control pills) are thought to reduce the risk of ovarian cancer by about 50 percent both in the general population and in women with harmful BRCA1 or BRCA2 mutations (30)

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About Elite Diagnotics

Elite Diagnostics is a Highly Complex CLIA certified Lab based in Crown Point, Indiana. We use state of the art technology coupled with rigorous quality control guidelines to provide prompt and reliable test results for physicians and their patients.