Breast Cancer

What is breast cancer?

Breast cancer happens when breast cells mutate and begin to grow and divide in an uncontrolled way, forming tumors. Breast cancer can be invasive, meaning that the cancer spreads into surrounding breast tissue and may spread to other parts of the body.

Breast cancer is one of the most common cancers in women, and it can also affect men. It typically affects women over 50, but younger women can also develop breast cancer.

Breast cancer symptoms aren’t always noticeable in the early stages. Regular breast cancer screening, including mammograms when recommended, can help detect breast cancer early, when it may be easier to treat.

Are there different types of breast cancer?

There are different types and subtypes of breast cancer. Determining the type and subtype can help doctors develop the most appropriate treatment plan.

Types of breast cancer include:

• Invasive ductal carcinoma (IDC): One of the most common types of breast cancer, it starts in the milk ducts and spreads into nearby breast tissue.
• Lobular breast cancer: This starts in the lobules, the glands that produce breast milk, and can spread to nearby breast tissue.
• Ductal carcinoma in situ (DCIS): This starts in the milk ducts and is considered noninvasive because the abnormal cells have not spread beyond the ducts.
• Triple-negative breast cancer (TNBC): A type of breast cancer that does not have estrogen or progesterone receptors or high levels of the HER2 protein. It can be more difficult to treat because some commonly used targeted treatments are not effective against it.
• Inflammatory breast cancer (IBC): A rare and aggressive type of breast cancer that can cause redness, swelling and other changes to the breast.
• Paget's disease of the breast: A rare type of breast cancer that affects the skin of the nipple and areola.

Breast cancer subtypes are classified based on whether cancer cells have certain receptors, which are proteins on the surface of or inside cells. These receptors can help cancer cells grow. Knowing which receptors are present can help doctors determine which treatments are most likely to be effective. Breast cancer may be classified as:

• ER-positive (ER+): The cancer cells have estrogen receptors.
• ER-negative (ER-): The cancer cells do not have estrogen receptors.
• PR-positive (PR+): The cancer cells have progesterone receptors.
• PR-negative (PR-): The cancer cells do not have progesterone receptors.
• HER2-positive (HER2+): The cancer cells have higher-than-normal levels of the HER2 protein.
• HER2-negative (HER2-): The cancer cells do not have higher-than-normal levels of the HER2 protein.

Breast cancer can also be described as hormone receptor-positive (HR-positive) when it has estrogen and/or progesterone receptors, or hormone receptor-negative (HR-negative) when it does not have either receptor.

What is metastatic breast cancer?

Metastatic breast cancer is breast cancer that has spread from the breast to other parts of the body, such as the lungs, brain, bones or liver. Metastatic breast cancer is also referred to as advanced breast cancer or stage IV breast cancer.

What are breast cancer symptoms?

Breast cancer symptoms can vary, and sometimes there are no noticeable symptoms. Common breast cancer symptoms include:

• A lump in your breast
• A change in the size or shape of your breast
• A thickening in your breast or underarm
• A change in the look or feel of your nipple
• A change in the look or feel of the skin on your breast, such as dimpling
• A hard area under the skin on your breast
• Discharge from your nipple (this may be clear or stained with blood)

If you notice any change in your breasts, always discuss it with your doctor.

What causes breast cancer?

Doctors don’t know exactly what causes breast cells to mutate and become cancerous, but there are risk factors that can increase the risk of developing breast cancer. These risk factors include:

• Age: The risk of breast cancer increases with age, although younger women can also develop the disease.
• Family history: Your risk may increase if you have a close relative who has breast cancer.
• Genes: Some breast cancers are associated with inherited genetic mutations in certain genes, including BRCA1 and BRCA2.
• Hormone replacement therapy: HRT may increase the risk of developing breast cancer.
• Radiation exposure: Previous exposure to radiation therapy, particularly to the chest, may increase the risk.
• Obesity
• Smoking
• Alcohol consumption

How is breast cancer diagnosed?

Following a physical examination, a mammogram may be performed to look for signs of breast cancer. Other tests may include:

• Ultrasound
• Magnetic resonance imaging (MRI)
• Biopsy

A biopsy is used to confirm whether abnormal cells are cancerous and can provide information about the type and characteristics of the cancer

How is breast cancer staged?

Once breast cancer is diagnosed, your doctor will determine the stage of the disease to help plan treatment. Breast cancer is staged based on factors including the size and location of the tumor, whether cancer has spread to nearby lymph nodes or other parts of the body, the grade of the cancer and certain biomarkers.

Breast cancer is generally classified from stage 0 to stage IV:

• Stage 0: Abnormal cells are present but have not spread beyond where they first developed, such as in ductal carcinoma in situ (DCIS).
• Stage I: The cancer is small and may be limited to the breast or may have spread to nearby lymph nodes.
• Stage II: The cancer may be larger and/or may have spread to nearby lymph nodes.
• Stage III: The cancer has spread to nearby lymph nodes, the skin of the breast or the chest wall but has not spread to distant parts of the body.
• Stage IV: The cancer has spread to distant parts of the body, such as the lungs, brain, bones or liver. This is also known as metastatic breast cancer.

How is breast cancer treated?

Treatment for breast cancer may involve surgery, such as:

• Lumpectomy: This procedure removes the tumor and a small amount of surrounding healthy tissue while preserving most of the breast.
• Mastectomy: This procedure removes the entire breast containing cancer.
• Breast reconstruction: Surgery after a mastectomy or lumpectomy to recreate the breast.

Breast cancer surgery may be combined with other treatments, such as

• Chemotherapy
• Immunotherapy
• Radiation therapy
• Hormone therapy
• Targeted therapy

The treatment recommended will depend on factors including the type and stage of breast cancer, and the patient's individual circumstances.

What are the side effects of breast cancer treatment?

Everyone reacts differently to breast cancer treatments. Your doctor will discuss any possible side effects with you before you undergo treatment. Common side effects of chemotherapy and radiotherapy include fatigue and nausea. Immunotherapy, hormone therapy and targeted therapies can also cause side effects, which vary depending on the treatment.

Like all surgeries, breast cancer surgery has potential complications, which your doctor will discuss in detail with you. Complications may include infection, neve damage, blood clots and lymphedema.

Can breast cancer be prevented?

There are things you can do that may reduce your risk of breast cancer developing, including:

• Maintain a healthy weight
• Eat a balanced diet
• Exercise regularly
• Quit smoking and reduce alcohol consumption

Attending regular mammograms when recommended is important because screening can detect some breast cancers before symptoms appear, when the disease may be easier to treat.

Regular breast self-exams can also help you become familiar with how your breasts normally look and feel.

If a close relative has had breast cancer, you may be at increased risk. Talk to your doctor about whether genetic counseling or testing for inherited breast cancer genes may be appropriate. Your doctor may also recommend more frequent screening or screening at a younger age.