Cancer occurs when there are mutations in genes that regulate cell growth. The mutations let the cells divide and multiply in an uncontrolled, chaotic way. The cells keep multiplying, producing progressively more abnormal copies rather than reverting towards being healthy cells. This eventually forms a tumor in most cases.
Breast cancer is cancer that develops in breast cells. Usually, the cancer forms in the lobules or ducts of the breast. These are the glands that produce milk and the pathways that help bring the milk from the glands to the nipple. Cancer can also occur in fatty and fibrous breast tissue. This is known as stromal tissue.
The uncontrolled cancer cells start to invade healthy breast tissue and can travel to the lymph nodes under the arms. The lymph nodes are a primary pathway that helps the cancer cells move to other parts of the body.
According to the American Cancer Society, approximately 232,240 new cases of invasive breast cancer were expected to be diagnosed in 2013. More than 64,000 non-invasive breast cancer diagnoses (carcinoma in situ) were also expected. More than 39,000 women were expected to die from the disease. Breast cancer can also be diagnosed in men, and it was estimated that in 2013, more than 2,000 men were diagnosed.
Several types of breast cancer exist. The type you have determines your treatment options, as well as your prognosis.
The most common types of breast cancer include:
Ductal carcinoma in situ. Ductal carcinoma in situ (DCIS) is a non-invasive precursor for cancer. If you have DCIS, the cells that line the ducts in your breast have changed and now look cancerous. Unlike cancerous cells, however, DCIS cells haven’t invaded the surrounding breast tissue.
Lobular carcinoma in situ. Lobular carcinoma in situ (LCIS) is cancer that grows in the milk-producing glands of your breast. However, the cancer cells haven’t yet invaded the surrounding tissue.
Invasive ductal carcinoma. Invasive ductal carcinoma (IDC) is the most common type of breast cancer. This type of breast cancer begins in your breast’s milk ducts and then invades nearby tissue in the breast. Once the breast cancer has spread to the tissue outside your milk ducts, it can begin to spread to other nearby organs and tissue.
Invasive lobular carcinoma. Invasive lobular carcinoma (ILC) first develops in your breast’s lobules, or milk-producing glands. If breast cancer is diagnosed as ILC, it has already spread to nearby tissue and organs.
Other types of breast cancer are less common. These include:
Inflammatory breast cancer. Inflammatory breast cancer (IBC) is an uncommon type. In IBC, cells block the lymph nodes, so the breast can’t properly drain. However, instead of creating a tumor, IBC causes your breast to swell, look red, and feel very warm. A cancerous breast may appear pitted and thick, like an orange peel. IBC makes up only slightly more than one percent of all breast cancer cases.
Triple-negative breast cancer. To be diagnosed as triple negative breast cancer, a tumor must have all three of the following characteristics:
- It must lack estrogen receptors.
- It must lack progesterone receptors.
- It must not have additional HER2 proteins on its surface. HER2 is a protein that fuels breast cancer growth.
If a tumor meets these three criteria, it’s labeled a triple-negative breast cancer. This type of breast cancer has a tendency to grow and spread more quickly than other types of breast cancer. Triple-negative breast cancers are also difficult to treat because traditional breast cancer treatments are not effective.
Paget disease of the nipple. This type of breast cancer begins in the breasts’ ducts, but as it grows, it begins to affect the skin and areola of your nipple. Paget disease may occur with other types of breast cancer, such as DCIS or IDC.
Phyllodes tumor. This very rare type of breast cancer grows in the connective tissue of the breast.
Angiosarcoma. Cancer that grows on the blood vessels or lymph vessels in your breast is called angiosarcoma.
There are several risk factors that can increase your chances of getting breast cancer. However, having any of these doesn’t mean you will definitely develop the disease.
Some risk factors can’t be avoided, like family history. Other risk factors, like smoking, you can change. You can take steps to help protect your health and get regular screening, which helps catch the disease at an earlier stage.
Risk factors include:
Age. Your risk for developing breast cancer increases as you age. Roughly 12 percent of invasive breast cancer occurs in women under age 45, but 66 percent of invasive breast cancers are found in women over age 55.
Drinking alcohol. Excessive alcohol consumption can increase your risk.
Dense breast tissue. Dense breast tissue makes mammograms hard to read. It also increases your risk for breast cancer.
Gender. Women are 100 times more likely to develop breast cancer than men.
Genes. Women who have the BRCA1 and BRCA2 gene mutations are more likely to develop breast cancer than women who don’t. Other gene mutations may affect your risk, too.
Early menstruation. If you had your first period before age 12, you have an increased risk for breast cancer.
Giving birth at an older age. Women who don’t have their first child until after age 35 have an increased risk of breast cancer.
Hormone therapy. Women who took or are taking postmenopausal estrogen and progesterone medications to reduce their signs of menopause have a higher risk of breast cancer.
Inherited risk. If a close female relative has had breast cancer, you have an increased risk for developing it. This includes your mother, grandmother, sister, or daughter. If you don’t have a family history of breast cancer, you can still develop breast cancer. In fact, the majority of women who develop it have no family history of the disease.
Late menopause start. Women who do not start menopause until after age 55 are more likely to develop breast cancer.
Never being pregnant. Women who never became pregnant and carried a pregnancy to full-term are more likely to develop breast cancer.
Previous breast cancer. If you have had breast cancer in one breast, you have a 3- to 4-fold increased risk of developing breast cancer in your other breast or in a different area of the previously affected breast.
Breast cancer may not cause any symptoms in its early stages. The tumor may be too small to be felt, but an abnormality can be seen on a mammogram. If the tumor can be felt, the first sign is usually a new lump in the breast that was not there before. Not all lumps are cancer. It’s a good idea to see your doctor if you find a lump.
Each type of breast cancer may cause a variety of symptoms. Many of these symptoms are similar, but some can be different. Symptoms for the most common breast cancers include:
- a lump or tissue thickening that feels different than surrounding tissue and has only recently developed
- red, pitted skin over the entire breast
- swelling in all or part of the breast
- a nipple discharge other than breast milk
- bloody discharge from your nipple
- peeling, scaling, or flaking of skin on the nipple or breast
- a sudden, unexplained change in the shape or size of your breast
- inverted nipple
- changes to the appearance of your breasts’ skin
- a lump or swelling under the arm
If you have any of these symptoms, it doesn’t mean you necessarily have breast cancer. Follow up with your doctor for further examination and testing.
To determine if your symptoms are caused by breast cancer or a benign breast condition, your doctor will want to conduct a thorough physical examination. They may also request one or more diagnostic tests to help understand what is causing the symptoms you are experiencing.
Tests that can help diagnose breast cancer include:
- Breast exam. Your doctor will conduct a thorough breast exam, checking both breasts for abnormal spots or signs of breast cancer. Your doctor may also check other parts of your body to see if the symptoms you’re experiencing could be related to another condition.
- Mammogram. Perhaps the best way to see below the surface of your breast is with an imaging test called a mammogram. Many women get annual mammograms to check for breast cancer. If your doctor suspects you may have a tumor or suspicious spot, they will also request a mammogram. If an abnormality is seen on your mammogram, your doctor may request additional tests.
- Ultrasound. A breast ultrasound creates a picture of the tissues deep in your breast. The ultrasound uses sound waves to do this. An ultrasound can help your doctor distinguish between a solid mass, like a tumor, and a benign cyst.
- Biopsy. If both a mammogram and an ultrasound are inconclusive, your doctor may wish to take a sample of the suspicious spot and have it tested. To do this, your doctor will remove a sample of the suspicious spot and send it to a laboratory. If the sample is positive for cancer, the lab can test it further in order to tell your doctor the type of cancer you have.
Breast cancer can be divided into stages based on how severe it is. Cancers that have grown and invaded nearby tissues and organs are at a higher stage than cancers that are still contained to the breast. In order to stage a breast cancer, doctors need to know:
- if the cancer is invasive or non-invasive
- how large the tumor is
- whether or not the lymph nodes are involved
- if the cancer has spread to nearby tissue or organs.
Breast cancer has five main stages. They are:
Stage 0. Stage 0 breast cancer is ductal carcinoma in situ (DCIS). DCIS is a type of pre-cancerous growth. Cancer cells in DCIS remain confined to the ducts in the breast and have not spread beyond the ducts and into nearby tissue.
Stage 1. Stage 1 tumors are no larger than 2 centimeters (cm). Lymph nodes are not impacted by stage 1 breast cancer.
Stage 2. Stage 2 breast cancers can be divided into two categories. The first type of stage 2 breast cancer has a tumor that is no larger than 2 cm, but the cancer has spread to lymph nodes. The second type of stage 2 breast cancer has a tumor that is between 2 and 5 cm, but the cancer has not spread to any lymph nodes or nearby tissue.
Stage 3. Several types of cancers can be at stage 3. The first is a tumor that is no larger than 5 cm, but this tumor has not spread to nearby lymph nodes or tissue. Breast cancer may be at stage 3 if the cancer has spread into the chest wall or skin but not the lymph nodes. Another type of stage 3 breast cancer can be a tumor of any size with lymph nodes in distant areas of the body having cancer, too.
Stage 4. Stage 4 breast cancer can have a tumor of any size, and the cancer has spread to nearby and distant lymph nodes, as well as distant organs.
How Is Breast Cancer Treated? | Treatment
Your breast cancer’s stage, how far it has invaded, and how big the tumor has grown all play a large part in determining which treatments you will need. Once your doctor has determined your cancer’s size, stage, and grade, the two of you can discuss your treatment options. Surgery is the most common treatment for breast cancer. In addition to surgery, most women with breast cancer undergo a complementary treatment, such as chemotherapy, radiation, or hormone therapy.
Several types of surgery may be used to remove breast cancer, including:
Lumpectomy. This procedure removes only the suspicious or cancerous spot, leaving most surrounding tissue in place.
Mastectomy. In this procedure, a surgeon removes an entire breast. In a double mastectomy, both breasts are removed.
Sentinel node biopsy. This surgery removes some of the lymph nodes that receive drainage from the tumor. These lymph nodes will be tested, and if they don’t have cancer, you may not need additional lymph-removing surgery.
Axillary lymph node dissection. If lymph nodes removed during a sentinel node biopsy test positive, your doctor may perform this procedure to remove additional lymph nodes.
Contralateral prophylactic mastectomy. Even though breast cancer may be present in only one breast, some women elect to have a contralateral prophylactic mastectomy. This surgery removes your healthy breast to reduce your risk of developing breast cancer again.
High-powered beams of X-rays can be used to target and kill cancer cells. Most radiation treatments use a large machine on the outside of the body (external beam radiation).
Advances in cancer treatment have brought about the ability to radiate cancer from inside the body. This type of radiation treatment is called brachytherapy. To conduct brachytherapy, surgeons place radioactive seeds or pellets inside the body, near the tumor site. The seeds stay there for a short period of time each day and work to reduce cancer cells.
Chemotherapy is a drug that can destroy cancer cells. Some patients may undergo chemotherapy alone, but this type of treatment is often used in conjunction with other treatments, especially surgery.
In some cases, doctors prefer to give patients chemotherapy before surgery. The hope is that the medicine will shrink the tumor so the surgery will not have to be as invasive. Chemotherapy has many unwanted side effects, so discuss your concerns with your doctor before beginning treatment with this powerful drug.
If your type of breast cancer is sensitive to hormones, your doctor may start you on therapy to block hormones to help slow and possibly stop the growth of your cancer. Estrogen and progesterone, two female hormones, can stimulate breast cancer tumor growth. Taking medicines to stop or block the production of these hormones may help slow the growth of your cancer.
Certain medications are designed to attack specific abnormalities or mutations within cancer cells. For example, Herceptin (trastuzumab) can block the production of the HER2 protein. HER2 helps breast cancer cells grow, so taking a medication to slow the protein production may help slow cancer growth.
If you detect an unusual lump or spot in your breast, make an appointment to see your doctor. Likewise, if you begin experiencing any of the symptoms of breast cancer without explanation, check to see if you can get an appointment with your doctor.
Conducting monthly self-examinations will help you detect changes in your breasts more quickly than if you examine yourself less frequently or not at all. Each year, during your annual check-up, your doctor should also check for changes in your breasts. Don’t be afraid to see your doctor about any suspicious spots. Early-stage breast cancer can often be treated easily and cured if found quickly enough. The longer breast cancer is allowed to grow, the more difficult treatment becomes.
Breast cancer doesn’t have an identifiable cause. For that reason, it can’t be prevented entirely. However, several of the risk factors that may lead to breast cancer can be addressed through a healthy lifestyle and strategic measures.
For example, women who are obese have a higher risk of developing breast cancer. Learning and maintaining a healthy diet may help lower your risk. The same goes for alcohol consumption. A daily glass of wine, spirits, or beer may not have a significant impact on your breast cancer risk, but having more than that each day may put you at a higher risk. Binge drinking also increases your risk for breast cancer.
Get regular exercise. Exercise helps shed unwanted pounds and can encourage you to maintain a healthier lifestyle.
Reduce the odds that your breast cancer will go undetected by having regular physical exams with your doctor. Many women should also receive yearly mammograms. Recommendations for mammograms are different for each woman, so talk with your doctor to see if you should get regular mammograms.
You may be the best line in the fight against breast cancer. Regular self-exams can help you detect possible breast cancer tumors before they are able to grow too large. Conduct self-exams at least once a month. Talk with your doctor about how to conduct this test.
Women who have an increased risk of breast cancer because of an inherited factor, such as gene mutations, may wish to act in a preventive fashion. If you know you have an increased risk of breast cancer, you might want to consider having a prophylactic mastectomy. This procedure removes healthy breasts in order to cut your risk of developing breast cancer.
Written by: Jaime Herndon & Kimberly Holland
Published on Aug 29, 2014
Medically reviewed on Aug 29, 2014 by Kenneth R. Hirsch, MD