Breast cancer is one of the most common cancers affecting women and those assigned female at birth (AFAB). This occurs when cancer cells in the breast grow and become a tumor.
About 80% of breast cancer cases are invasive, meaning the tumor can spread from the breast to other areas of the body. Breast cancer usually occurs in women over the age of 50, but it can also occur in women under the age of 50 and their AFAB individuals. Men and those assigned male at birth (AMAB) can also develop breast cancer.
Types of Breast Cancer
By identifying the type and subtype of cancer, health care providers can tailor treatment to minimize side effects and maximize effectiveness. Some common types of breast cancers are provided below:
- Invasive ductal carcinoma (IDC): This cancer begins in the breast ducts and spreads to surrounding breast tissue. This type of breast cancer is usually found in the United States.
- Lobular breast cancer: This breast cancer begins in the milk-producing glands (lobules) in the breast and often spreads to surrounding breast tissue. It is the second most common breast cancer in the United States.
- Ductal carcinoma in situ (DCIS): Like IDC, this type of cancer starts in female’s milk ducts. The difference is DCIS doesn’t spread beyond your milk ducts.
Less common breast cancer types include:
- Triple-negative breast cancer (TNBC): This invasive cancer is aggressive in nature and spreads more quickly than any other types of breast cancers.
- Inflammatory breast cancer (IBC): This is a rare and fast-growing cancer that looks like a rash on the breast. IBC is rare in nature.
- Paget’s disease of the breast: This rare cancer affects the skin of the nipple and can look like a rash. Less than 4% of all breast cancers are Paget’s disease of the breast.
Breast Cancer Subtypes
Health care providers classify breast cancer subtypes by the status of the receptor cells. Receptors are protein molecules in or on the cell surface. These can attract or bind to certain substances in the blood, including hormones such as estrogen and progesterone. Estrogen and progesterone support cancer cell growth. Determining whether cancer cells have estrogen or progesterone receptors can help health care providers plan breast cancer treatment.
Subtypes include:
- ER-positive (ER+) breast cancer has estrogen receptors.
- PR-positive (PR+) Breast cancer has progesterone receptors.
- HR-positive (HR+) breast cancer has estrogen and progesterone receptors.
- HR-negative (HR) breast cancer has no estrogen or progesterone receptors. 4,444 HER2-positive (HER2+) breast cancers with higher than normal levels of HER2 protein. This protein helps cancer cells grow. Approximately 15-20% of all breast cancers are HER2 positive.
Symptoms and Causes
Common signs of breast cancer and things to watch out for.
What are the symptoms of breast cancer?
This condition can affect the breasts in a variety of ways. Some of the symptoms of breast cancer are very noticeable. Other areas are simply areas that look completely different from the rest of the chest. Breast cancer may also not cause any noticeable symptoms. But when it does, symptoms may include:
- Changes in breast size, shape, or contour.
- A lump or mass that may feel small, like a pea.
- A lump or thickening in or near the breasts or in the armpits that persists throughout the menstrual cycle.
- Changes in the appearance or feel of the skin on the breast or nipples. The skin may appear pitted, wrinkled, flaky, or irritated. It may appear red, purple, or darker than the rest of the breast.
- A marble-like area under the skin.
- Discharge of bloody or clear fluid from the nipples.
What is the cause of breast cancer?
Experts know that breast cancer occurs when breast cells mutate to become cancerous cells, divide and multiply to form tumors. They don’t know what is causing this change. However, research shows that there are several risk factors that can increase your risk of developing breast cancer. These include:
Age: 55+ years
Gender: Women and AFAB patients develop the disease much more often than men and AMAB patients.
Family history: If a parent, sibling, child, or other close family member has breast cancer, you are at risk of developing breast cancer.
Genetics: Up to 15% of breast cancer patients develop breast cancer because they have inherited a genetic mutation. The most common genetic mutations affect the BRCA1 and BRCA2 genes.
Smoking: Tobacco use is associated with many types of cancer, including breast cancer.
Consumption of alcoholic beverages: Research shows that consumption of alcoholic beverages may increase the risk of breast cancer. 4,444 people are obese.
Radiation Exposure: You are more likely to develop breast cancer if you have previously had radiation therapy, especially to the head, neck, and chest.
Hormone Replacement Therapy: People who use hormone replacement therapy (HRT) are at increased risk of being diagnosed with this condition.
Diagnosis and Testing
How is breast cancer diagnosed?
Your healthcare provider may perform a physical exam or order a mammogram to detect signs of breast cancer. However, the following tests are performed to diagnose the disease:
- Breast ultrasound.
- Breast magnetic resonance imaging (MRI).
- Breast biopsy.
- Immunohistochemical test for hormone receptors.
- genetic tests to identify mutations that cause breast cancer.
Breast Cancer Stages
Healthcare providers use cancer staging systems to plan treatment. Cancer staging also helps doctors determine prognosis, or what to expect after treatment. The stage of breast cancer depends on factors such as the type of breast cancer, the size and location of the tumor, and whether the cancer has spread to other areas of the body. The stages of breast cancer are:
Stage 0: The disease is non-invasive, meaning it has not spread from the mammary gland to other parts of the breast.
Stage I: There are cancer cells in nearby breast tissue.
Stage II: Cancer cells have formed one or more tumors. The tumor is less than 2 cm in diameter and has spread to the axillary lymph nodes, or it is larger than 5 cm and has not spread to the axillary lymph nodes. Tumors at this stage are 2 to 5 centimeters in diameter and may or may not affect nearby lymph nodes.
Stage III: Breast cancer is present in surrounding tissues and lymph nodes. Stage III is usually called locally advanced breast cancer.
Stage IV: Cancer has spread from the breast to areas such as the bones, liver, lungs, or brain.
How is breast cancer treated?
The main treatment for breast cancer is surgery, but your healthcare provider may use other treatments. Breast cancer surgeries include:
- Mastectomy.
- Pneumectomy.
- Breast reconstruction.
Your healthcare provider may combine surgery with one or more of the following treatments:
- Chemotherapy.
- Radiation therapy, including intraoperative radiation therapy (IORT).
- Immunotherapy.
- Hormone therapy, including selective estrogen receptor modulator therapy (SERM).
- Targeted therapy.