Understanding Breast Cancer
Breast cancer is the most common form of internal cancer in women and the second most common cause of cancer death for women in the U.S.
More than 260,000 women in the United States will be diagnosed with some form of breast cancer this year. 41,000 of them will die in 2019 from the disease. One in eight women will develop breast cancer in her lifetime.
About 85% of breast cancers occur in women who have no family history of breast cancer. While most cases of breast cancer are diagnosed in women, more than 2,000 new cases of breast cancer are diagnosed in American men each year.
For either sex, symptoms of breast cancer may be detectable through breast self-exam or a doctor’s exam and mammography. The most common sign of breast cancer is a lump found in the breast or armpit area, but there are several other possible signs and symptoms. Since symptoms of breast cancer can be related to noncancerous breast conditions, further evaluation is almost always required to confirm a diagnosis.
The American Cancer Society recommends that those 40 to 44 years of age have the option to begin annual mammography; those 45 to 54 undergo annual mammography; and those 55 years of age and older may transition to biennial mammography or continue annual mammography. Women should continue mammography as long as overall health is good and life expectancy is 10 or more years.
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Finding a Lump or Hard Knot
Breast tissue is naturally lumpy, but some women may detect a lump or knot that feels harder or thicker than surrounding tissue. Not every lump is cancerous. Some lumps are related to a woman’s menstrual cycle and disappear after menstruation, or a lump may indicate a benign cyst. However, if you ever notice any type of unusual growth you should be seen by a doctor.
Dimpled Skin
Dimpled or puckered skin can be a sign of breast cancer, as can large visible pores. Or, the skin may take on an orange-peel-like appearance. If one or both of your breasts show any of those indicators, don’t wait – call your physician.
Skin Signs
If you notice patches of skin on your breast, nipple or areola – the darkened skin surrounding the nipple — pay close attention. If those areas become scaly, itchy, and red or darkened, or your breast feels warm where irritations have broken out, see your doctor.
Changes in Breast Size
If you are not breastfeeding, sudden swelling in one or both breasts may indicate a blockage that causes lymph fluid to back up. A problem with your lymph nodes may also appear as swelling in your collarbone or armpits. If one or both breasts shrink unexpectedly, it may be a sign of significant hormonal changes, which can be a trigger for cancer.
It’s normal to have one breast that is slightly larger than the other, but if you notice a recent change in your breasts, bring this up with your doctor.
Nipple Changes
Some types of breast cancers cause the nipple to retract or completely invert. If this is not normal for you, see a doctor. Conditions such as pregnancy, breastfeeding, and aging can also cause these changes. Some people are born with inverted nipples, too.
Nipple Discharge
A discharge from your nipple, whether clear or bloody, may indicate a tumor. But an infection or an injury to your breast can cause a discharge too. It helps to be aware of any discharge and to keep track of it. If it persists, see your doctor.
Breast Pain
Breast pain makes the list of common symptoms, but be aware that while some breast cancers cause pain in the breast, most do not. Studies have shown that only about five percent of women diagnosed with breast cancer have pain as their main symptom.
Breast cancer is cancer that starts in the tissues of the breast.
There are two main areas of the breast where breast cancer starts:
- Ductal carcinoma starts in the tubes (ducts) that move milk from the breast to the nipple. Most breast cancers are ductal.
- Lobular carcinoma starts in the lobules, the parts of the breast that produce milk.
Breast cancer can be invasive or noninvasive.
Invasive means it has spread from the milk duct or lobule to other tissues in the breast. Noninvasive means it has not yet invaded other breast tissue. Noninvasive breast cancer is called “in situ.”
Lobular carcinoma in situ
Lobular carcinoma in situ (LCIS) is an area (or areas) of abnormal cell growth that increases a person’s risk of developing invasive breast cancer later on in life. Lobular means that the abnormal cells start growing in the lobules, the milk-producing glands at the end of breast ducts. Carcinoma refers to any cancer that begins in the skin or other tissues that cover internal organs — such as breast tissue. In situ or “in its original place” means that the abnormal growth remains inside the lobule and does not spread to surrounding tissues
Despite the fact that its name includes the term “carcinoma,” LCIS is not a true breast cancer. Rather, LCIS is an indication that a person is at higher-than-average risk for getting breast cancer at some point in the future.
Ductal Carcinoma in Situ
Ductal carcinoma in situ (DCIS) is a non-invasive cancer where abnormal cells have been found in the lining of the breast milk duct. The term “situ” in the title means “in its original place.” Therefore, these atypical cells have not spread outside of the ducts into the surrounding breast tissue. Ductal carcinoma in situ is very early cancer that is highly treatable, but if left untreated or undetected, it can spread into the surrounding breast tissue. When you have had DCIS, you are at higher risk for cancer coming back or for developing new breast cancer than a person who has never had breast cancer before.
Invasive Ductal Carcinoma
Invasive ductal carcinoma (IDC), sometimes called infiltrating ductal carcinoma, is the most common type of breast cancer. The abnormal cancer cells that began forming in the milk ducts have spread beyond the ducts into other parts of the breast tissue. Invasive cancer cells can also spread to other parts of the body. IDC is the most common type of breast cancer, making up nearly 70-80% of all breast cancer diagnoses. It is also the type of breast cancer that most commonly affects men.
Inflammatory Breast Cancer
Inflammatory breast cancer is an aggressive and fast-growing breast cancer in which cancer cells infiltrate the skin and lymph vessels of the breast. It often produces no distinct tumor or lump that can be felt and isolated within the breast. But when the lymph vessels become blocked by the breast cancer cells, symptoms begin to appear. It is a rare and aggressive form of breast cancer.
Metastatic Breast Cancer
Metastatic breast cancer is also classified as Stage 4 breast cancer. The cancer has spread to other parts of the body. This usually includes the lungs, liver, bones or brain. Keep in mind that a recurrence of breast cancer or metastatic (advanced) disease is NOT hopeless. Many women continue to live long, productive lives with breast cancer in this stage. It is also likely that your experience with treatment this time will be somewhat different from last time. There are so many options for your care and so many ways to chart your progress as you move through diagnosis, treatment, and beyond.
Your pathology report will include the results of a hormone receptor assay, a test that tells you whether or not the breast cancer cells have receptors for the hormones estrogen and progesterone. Hormone receptors are proteins — found in and on breast cells — that pick up hormone signals telling the cells to grow.
One major way of defining your type of breast cancer is whether or not it is:
- Endocrine receptor (estrogen or progesterone receptor) positive
- HER2 positive
- Triple negative, not positive to receptors for estrogen, progesterone, or HER2
- Triple positive, positive for estrogen receptors, progesterone receptors, and HER2
These classifications provide doctors with valuable information about how the tumor acts and what kind of treatments may work best.
Estrogen-receptor-positive (ER+)
A cancer is called estrogen-receptor-positive ( ER+) if it has receptors for estrogen. This suggests that the cancer cells, like normal breast cells, may receive signals from estrogen that could promote their growth.
Progesterone-receptor-positive (PR+)
A cancer is progesterone-receptor-positive (PR+) if it has progesterone receptors. This means that the cancer cells may receive signals from progesterone that could promote their growth.
Roughly two out of every three breast cancers test positive for hormone receptors.
HER-2 positive (HER-2+)
A cancer is HER-2 positive (HER-2+) if the cancer cells have too much of a growth-promoting protein known as HER2 protein, which promotes the growth of cancer cells. In about one of every five breast cancers, the cancer cells make an excess of HER2, due to a gene mutation. Cancer cells that have too many copies of the HER-2 gene produce too much of the growth-promoting protein called HER-2. Medications are available to shut down the HER-2 protein, thus slowing the growth and killing these cancer cells.
Triple Negative
A cancer that is neither estrogen-receptor-positive, progesterone-receptor-positive or HER-2-positive is referred to as Triple Negative Breast Cancer. This type of cancer is typically more aggressive and does not respond to hormone therapies.
Testing for hormone receptors is important because the results help you and your doctor decide whether the cancer is likely to respond to hormonal therapy or other treatments. Hormonal therapy includes medications that either (1) lower the amount of estrogen in your body or (2) block estrogen from supporting the growth and function of breast cells. If the breast cancer cells have hormone receptors, then these medications could help to slow or even stop their growth. If the cancer is hormone-receptor-negative (triple negative), then hormonal therapy is unlikely to work. You and your doctor will then choose other kinds of treatment.
Breast Cancer Staging System – TNM
The breast cancer staging system, called the TNM system, is overseen by the American Joint Committee on Cancer (AJCC). The AJCC is a group of cancer experts who oversee how cancer is classified and communicated. This is to ensure that all doctors and treatment facilities are describing cancer in a uniform way so that the treatment results of all people can be compared and understood.
In the past, stage number was calculated based on just three clinical characteristics, T, N, and M:
- the size of the cancer tumor and whether or not it has grown into nearby tissue (T)
- whether cancer is in the lymph nodes (N)
- whether the cancer has spread to other parts of the body beyond the breast (M)
- Numbers or letters after T, N, and M give more details about each characteristic. Higher numbers mean the cancer is more advanced
In 2018, the AJCC updated the breast cancer staging guidelines to add other cancer characteristics to the T, N, M system to determine a cancer’s stage:
- tumor grade: a measurement of how much the cancer cells look like normal cells
- estrogen- and progesterone-receptor status: do the cancer cells have receptors for the hormones estrogen and progesterone?
- HER2 status: are the cancer cells making too much of the HER2 protein?
- Oncotype DX score, if the cancer is estrogen-receptor-positive, HER2-negative, and there is no cancer in the lymph nodes
Adding information about tumor grade, hormone-receptor status, HER2 status, and possibly Oncotype DX test results has made determining the stage of a breast cancer more complex, but also more accurate.
Stage 0
Stage 0 is used to describe non-invasive breast cancers, such as DCIS (ductal carcinoma in situ). In stage 0, there is no evidence of cancer cells or non-cancerous abnormal cells breaking out of the part of the breast in which they started, or getting through to or invading neighboring normal tissue.
Stage I
Stage I describes invasive breast cancer (cancer cells are breaking through to or invading normal surrounding breast tissue) Stage I is divided into subcategories known as IA and IB.
In general, stage IA describes invasive breast cancer in which:
- the tumor measures up to 2 centimeters (cm) and
- the cancer has not spread outside the breast; no lymph nodes are involved
- there is no tumor in the breast; instead, small groups of cancer cells — larger than 0.2 millimeter (mm) but not larger than 2 mm — are found in the lymph nodes or
- there is a tumor in the breast that is no larger than 2 cm, and there are small groups of cancer cells — larger than 0.2 mm but not larger than 2 mm — in the lymph nodes
Still, if the cancer is estrogen-receptor-positive or progesterone-receptor-positive, it is likely to be classified as stage IA.
Microscopic invasion is possible in stage I breast cancer. In microscopic invasion, the cancer cells have just started to invade the tissue outside the lining of the duct or lobule, but the invading cancer cells can’t measure more than 1 mm.
Stage II
Stage II is divided into subcategories known as IIA and IIB.
In general, stage IIA describes invasive breast cancer in which:
- no tumor can be found in the breast, but cancer (larger than 2 millimeters [mm]) is found in 1 to 3 axillary lymph nodes (the lymph nodes under the arm) or in the lymph nodes near the breast bone (found during a sentinel node biopsy) or
- the tumor measures 2 centimeters (cm) or smaller and has spread to the axillary lymph nodes or
- the tumor is larger than 2 cm but not larger than 5 cm and has not spread to the axillary lymph nodes
Still, if the cancer tumor measures between 2 and 5 cm and:
- has not spread to the lymph nodes or parts of the body away from the breast
- is HER2-negative
it will likely be classified as stage I.
Similarly, if the cancer tumor measures between 2 and 5 cm and:
- has not spread to the lymph nodes
- is HER2-negative
- is estrogen-receptor-positive
- is progesterone-receptor-negative
- has an Oncotype DX Recurrence Score of 9
it will likely be classified as stage IA.
In general, stage IIB describes invasive breast cancer in which:
- the tumor is larger than 2 cm but no larger than 5 centimeters; small groups of breast cancer cells — larger than 0.2 mm but not larger than 2 mm — are found in the lymph nodes or
- the tumor is larger than 2 cm but no larger than 5 cm; cancer has spread to 1 to 3 axillary lymph nodes or to lymph nodes near the breastbone (found during a sentinel node biopsy) or
- the tumor is larger than 5 cm but has not spread to the axillary lymph nodes
Still, if the cancer tumor measures between 2 and 5 cm and:
- cancer is found in 1 to 3 axillary lymph nodes
- is HER2-positive
- estrogen-receptor-positive
- progesterone-receptor-positive
it will likely be classified as stage I.
Stage III
Stage III is divided into subcategories known as IIIA, IIIB, and IIIC.
In general, stage IIIA describes invasive breast cancer in which either:
- no tumor is found in the breast or the tumor may be any size; cancer is found in 4 to 9 axillary lymph nodes or in the lymph nodes near the breastbone (found during imaging tests or a physical exam) or
- the tumor is larger than 5 centimeters (cm); small groups of breast cancer cells (larger than 0.2 millimeter [mm] but not larger than 2 mm) are found in the lymph nodes or
- the tumor is larger than 5 cm; cancer has spread to 1 to 3 axillary lymph nodes or to the lymph nodes near the breastbone (found during a sentinel lymph node biopsy)
Still, if the cancer tumor measures more than 5 cm across and:
- is grade 2
- cancer is found in 4 to 9 axillary lymph nodes
- is estrogen-receptor-positive
- is progesterone-receptor-positive
- is HER2-positive
it will likely be classified as stage IB.
In general, stage IIIB describes invasive breast cancer in which:
- the tumor may be any size and has spread to the chest wall and/or skin of the breast and caused swelling or an ulcer and
- may have spread to up to 9 axillary lymph nodes or
- may have spread to lymph nodes near the breastbone
Still, if the cancer tumor measures more than 5 cm across and:
- is grade 3
- cancer is found in 4 to 9 axillary lymph nodes
- is estrogen-receptor-positive
- is progesterone-receptor-positive
- is HER2-positive
it will likely be classified as stage IIA.
Inflammatory breast cancer is considered at least stage IIIB. Typical features of inflammatory breast cancer include:
- reddening of a large portion of the breast skin
- the breast feels warm and may be swollen
- cancer cells have spread to the lymph nodes and may be found in the skin
In general, stage IIIC describes invasive breast cancer in which:
- there may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast and
- the cancer has spread to 10 or more axillary lymph nodes or
- the cancer has spread to lymph nodes above or below the collarbone or
- the cancer has spread to axillary lymph nodes or to lymph nodes near the breastbone
Still, if the above-mentioned cancer tumor measures any size and:
- is grade 2
- is estrogen-receptor-positive
- is progesterone-receptor-positive
- is HER2-positive or negative
it will likely be classified as stage IIIA.
Stage IV
Stage IV describes invasive breast cancer that has spread beyond the breast and nearby lymph nodes to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver, or brain.
You may hear the words “advanced” and “metastatic” used to describe stage IV breast cancer. Cancer may be stage IV at first diagnosis, called “de novo” by doctors, or it can be a recurrence of a previous breast cancer that has spread to other parts of the body.