Breast Cancers

Learn more about breast cancers and how they are treated.

Overview

Breast cancer can start in different parts of the breast. It can also spread to areas outside the breast through blood vessels and lymph vessels.

When breast cancer spreads to other parts of the body this is called metastasis.

There are many different factors that contribute to cancer risk, such as environmental exposures and lifestyle factors. Some people are carriers of a genetic mutation than causes a higher risk of breast cancer.

Depending on your medical and family history, we may offer genetic counselling to determine if you are eligible for high-risk screening or genetic testing.

Our clinic

Learn more about the specialized care provided at Mount Sinai Hospital for breast cancer.

This content is intended for informational purposes only and is not intended to be used or relied upon for any diagnostic or treatment purposes. It does not replace the need for consultation with a health-care professional. Please speak with your health-care professional for questions about your health.

Types

Types of breast cancer

Invasive ductal carcinoma and invasive lobular carcinoma are the most common types of breast cancer.

There are several other less common kinds of breast cancer, such as Paget’s disease, external medullary, mucinous, and inflammatory breast cancer.

Invasive ductal carcinoma

Invasive ductal carcinoma starts in the ducts in your breasts. It then grows into other parts of the breast tissue. Invasive cancer cells can also spread to other parts of the body.

Invasive lobular carcinoma

Invasive lobular carcinoma starts in the lobules, which are the glands that produce breast milk. It then spreads to the nearby breast tissue. From there, it may also spread to other parts of the body.

Ductal carcinoma in situ (DCIS)

Ductal carcinoma in situ (DCIS) is a breast disease that may lead to breast cancer. In patients with DCIS, cancer cells are only in the lining of the ducts, and have not spread to other tissues in the breast.

Diagnosis

Breast cancer diagnosis

There are several tests used to diagnose breast cancer. More than one test (or other tests that are not listed) may be needed to make an accurate diagnosis.

Breast exam

During a breast exam, a physician checks both breasts and the lymph nodes in and around your armpit, feeling for any lumps or other abnormalities. Breast cancer cells usually form a tumour that can be seen on an X-ray or felt as a lump.

Mammogram

A mammogram is an X-ray of the breast. It can help detect breast cancer in patients who do not have any symptoms. Mammograms can also help physicians get a closer look at a lump in the breast.

Breast ultrasound

A breast ultrasound uses sound waves to produce images of structures deep within the body. This helps physicians see if there are any abnormalities.

Breast magnetic resonance imaging (MRI)

An MRI machine uses a magnet and radio waves to create pictures of the inside of your breast. This helps physicians see if there are any abnormalities.

Biopsy

When an imaging test suggests that cancer is present, a biopsy is needed to make a definite diagnosis.

During a biopsy, a physician removes a small amount of tissue so it can be examined under a microscope and analyzed by a pathologist.

A pathologist is a physician who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.

Cancer staging

If cancer is found, the next step is determining the stage of cancer. Knowing the stage of your cancer helps your care team develop your treatment plan. Physician determine the stage of your cancer based on the size and location of the tumour, whether cancer cells are in the lymph nodes and whether there are cancer cells in other parts of the body.

Treatment

Breast cancer treatment

If you have been diagnosed with breast cancer, your cancer care team will discuss your treatment options and help you weigh the benefits of each treatment option against the possible risks and side effects.

Surgery

Most patients with breast cancer have surgery as part of their care plan. The surgeon may remove only the lump (lumpectomy) or the whole breast (mastectomy). The surgeon may also remove some of the underarm lymph nodes if necessary. Learn more about our breast surgical services.

Medical oncology

Medical oncology treats cancer with medications that affect the whole body. This includes chemotherapy and hormone therapy. Learn more about breast medical oncology.

Chemotherapy and hormone therapy are used to reduce the risk of the cancer spreading (adjuvant therapy) or to prolong survival when cancer has already spread elsewhere in the body (metastasized).

Most patients are referred for chemotherapy after having surgery for breast cancer. In some cases, you may see a medical oncologist before having surgery.

If you receive hormone therapy, you take medications to change the levels of certain hormones in your body. These changes to hormone levels can help slow down the growth of the tumour.

This treatment is often used to treat hormone receptor-positive breast cancers, which are cancers that respond to hormones. Post-menopausal women receive different hormonal therapy drugs than premenopausal women.

Radiation therapy

In many cases, radiation therapy is part of the treatment plan after breast-conserving surgery. In some cases, you may also receive radiation therapy after a mastectomy. It is also used to treat breast cancer that has spread to the bones, lungs or brain.

Targeted therapy

Immunotherapy, also called biologic therapy, is a treatment that uses your immune system to fight the cancer. Your cancer cells may produce proteins that prevent the immune system from attacking them. Immunotherapy medications interfere with that process to target, improve or restore the functioning of your immune system.

This treatment may be given alone or in combination with chemotherapy, hormonal therapy or both.

Clinical trials

Some patients may be able to participate in a research study that helps physicians and researchers find ways to improve treatments and quality of life for patients living with breast cancer.