The ABCs of Breast Cancer

A glossary of the breast cancer terms you have questions about.


Adjuvant therapy is a secondary method of treatment that is performed after the primary treatment method to lower the risk of the cancer returning. Examples include: chemotherapy and radiation therapy. 

Advanced Breast Cancer

Advanced breast cancer is another term used to describe metastatic breast cancer (see definition). It is not a different type of breast cancer. Rather, it is the most advanced stage (stage IV) of breast cancer.

Advanced Care Planning

Advanced care planning is the process of deciding ahead of time the kind of health and personal care you want in the future if you were to reach the point where you can no longer speak for yourself.

Axillary Lymph Node Dissection

Lymph nodes are small glands located in the underarm area. When someone’s lymph nodes are removed it’s called an axillary lymph node dissection. This surgery is usually combined with a mastectomy (see “mastectomy” definition). 


Benign is an adjective used to describe a tumour that is non-cancerous.    


A biopsy is the removal of tissues and/or cells to be examined by a pathologist (see “pathology” definition). This is usually the only way to tell for certain if a lump in your breast is benign or cancerous.

BRCA Genes

There are two BRCA genes: BRCA 1 and BRCA 2. Everyone has them and they protect us from getting breast and ovarian cancers. However, BRCA gene mutations can be inherited, which actually increase a person’s risk of developing these cancers, as well as prostate cancer in men. Women with BRCA gene mutations have a 40%-85% chance of developing breast cancer.

Breast Cancer

Breast cancer is cancer (the overproduction of cells) produced in the breast tissue. The majority of people diagnosed with breast cancer have random mutations arising during DNA replication in normal, noncancerous stem cells. 


A carcinoma is a type of cancer that begins in skin cells or in the tissue lining organs like the liver or kidneys.     

CDK Inhibitors

A CDK (cyclin-dependent kinase) inhibitor is any chemical that inhibits the function of CDKs. They are used to treat cancers by preventing the over proliferation of cancer cells. They are also called AT7519M. Right now there are many breakthrough breast cancer CDK inhibitors coming to market.


Chemotherapy (or chemo for short) is a type of cancer treatment that that stops cancer cells from dividing or kills them altogether. Chemo has many forms, like: an injection, a pill, or infusion.

Clinical Trial

Clinical trials are a way to test new medical advancements (treatment, prevention, screening, diagnosis, etc.) in humans before making them readily available to all.    


DCIS (ductal carcinoma in situ), occurs when abnormal cells are found in the lining of the breast duct, but have not spread to other parts of the breast tissue (non-invasive).   

De Novo

De Novo is a term, often associated with metastatic breast cancer (see definition), to describe a person’s first occurrence of cancer.  

EBC (Early Breast Cancer)

EBC is breast cancer that is contained in the breast. It has been detected before it’s spread to the lymph nodes or the armpit.   

End of Life Care

End of life care is treatment that focuses on improving a patient’s quality life after their illness has become terminal and/or incurable.   

Estrogen Receptor Positive

Estrogen Receptor Positive (ER+) is used to describe breast cancer cells that may receive signals from the hormone estrogen to promote their growth.   


FEC is a chemotherapy treatment that combines three chemotherapy drugs: 5 fluorouracil, epirubicin, and cyclophosphamide – which help stop cancer cells from growing or kill them altogether.   


Genes hold a person’s DNA and are the basic function of hereditary.     

Genetic Counselling

Genetic counselling is a series of conversations between a trained health professional and a person who is concerned about their risk of inheriting a disease.  

Germline testing

Germline testing (also known as genetic testing), usually occurs after genetic counseling to determine a persons familial risk of cancer.   


If you’re HER2-positive, your cancer cells make an excess amount of the HER2 protein. Originally made to control a breast cell’s growth, when the HER2 protein doesn’t work properly, breast cells can overproduce. This breast cancer tends to be aggressive, but there have been important breakthroughs in treatment.

High Risk

High risk refers to the certain factors that increase a person’s risk of developing breast cancer – more so than just the average person. They include: genetic, familial, and personal factors. 

Hormonal Therapy

Hormone Therapy (HT) uses drugs to block the production of estrogen and other female hormones that promote the growth of certain kinds of cancer cells after surgery.  


A program that gives special care to people who are near the end of life and have stopped treatment to cure or control their disease. Hospice offers physical, emotional, social, and spiritual support for patients and their families. The main goal of hospice care is to control pain and other symptoms of illness so patients can be as comfortable and alert as possible. It is usually given at home, but may also be given in a hospice center, hospital, or nursing home.

IDC (Invasive Ductal Carcinoma)

IDC (or invasive ductal carcinoma) is a type of breast cancer that starts in the milk ducts of the breast and has spread to surrounding breast tissues. It is the most common type of breast cancer.  

ILC (Invasive Lobular Carcinoma)

ILC (or invasive lobular carcinoma) is a type of breast cancer that starts in the milk-producing lobules of the breast and has spread to surrounding breast tissue. It is the second most common type of breast cancer, next to IDC (invasive ductal carcinoma).


Immunotherapy is a form of cancer treatment the body’s immune system to fight cancer by boosting it with treatments and substances that improve the body’s natural response to illness. 

Invasive Breast Cancer

Breast cancer becomes invasive when it has moved from where it originally started to now affect surrounding normal tissues. The most common form is invasive ductal carcinoma (see definition).

Locally Advanced

Locally advanced is a term to describe cancer that has spread from its original location to surrounding tissue or lymph nodes.   


A lumpectomy is a breast cancer surgery that removes the cancer and part of the abnormal surrounding tissue, but not the entire breast.   


Lymphedema is a common side effect of cancer treatment condition where the lymph nodes produce excess fluid, causing them to swell.   


Malignant is an adjective used to describe a tumour that is cancerous. They can destroy and spread to surrounding tissues.   


A mammogram is a form of breast cancer screening where an x-ray is taken of the breast.    


A mastectomy is a surgery done to remove part or all of the breast that has cancer.     


Menopause occurs when a woman stops having menstrual periods because her ovaries no longer produce hormones. Natural menopause usually occurs around the age of 50. Sometimes, a side effect of cancer treatment for young women is early menopause.


When cancer cells metastasize, they spread to other parts of the body.    

Metastatic Breast Cancer

Metastatic breast cancer (MBC) is cancer that’s spread to other parts of the body. When breast cancer is found outside the breast, it is still made up of breast cancer cells and still considered breast cancer.

NED (“No Evidence of Disease”)

NED (or “no evidence of disease”) is a term used when tests show no presence of cancer cells in someone who was previously being treated for cancer. NED has replaced the term remission because it is more accurate.

Neo-adjuvant Therapy

Neo-adjuvant therapy usually occurs before the primary cancer treatment (ie/ surgery). It includes chemotherapy, radiation therapy, and hormone therapy used to shrink the cancerous tumour. 


Chemotherapy treatment can often kill non-cancerous cells in the body in addition to the cancerous ones. Neutropenia is often a side effect that occurs when the body’s white blood cell count is too low because of this. 


An oncologist is a doctor who specializes in diagnosing and treating cancer with chemotherapy or in some cases immunotherapy.  


An oophorectomy is surgery to remove one or both of a woman’s ovaries.     

Palliative Care

Palliative care given specifically to people suffering from a life-long or life-threatening illness. This kind of care focuses on improving patients’ quality of life (see definition), focusing on all aspects of having an illness: physical, psychological, spiritual, etc.


Pathology is the study of diseases by examining tissues under a microscope.    

Peer Support

Peer support connects people living with cancer or people with other illnesses to others who have gone through it. Peer support is not based on psychiatric models and diagnostic criteria.


Progesterone is a hormone that plays a role in the menstrual cycle and pregnancy. If the breast cancer is Progesterone receptor-positive (PR+), that means its cells may receive signals from progesterone that promote their growth. 


A prognosis is typically given by a doctor. It indicates the likely course that a disease or illness will take, including the chances of it recurring.  

Quality of Life (QOL)

Cancer treatments and clinical trials are often concerned with improving patients’ quality of life (QOL). This refers to their overall enjoyment of life and their wellbeing.   

Radiation Therapy

Radiation Therapy uses high-energy X-rays to destroy any cancer cells that may remain in the breast after surgery. This reduces the chance of recurrence.  


Situ is used to describe a tumour, cancer, etc. which is confined to where it first started. In other words, it hasn’t spread. For example, ductal carcinoma in situ, is a breast cancer found in the milk ducts which has not spread to other tissues or parts of the body.


Stage is a term used to diagnose how advanced breast cancer is. It’s determined by tumour size, the number of lymph nodes affected, and whether it has spread to other tissues and/or parts of the body.


The state of being a survivor. Survivorship refers to a community of individuals who are living their best lives post-cancer and the resources and tools they can use to do so.   


Tamoxifen is a cancer drug used to treat and/or prevent certain types of breast cancer in women and men. It’s often used to treat ductal carcinoma in situ (see definition) or to prevent breast cancer in women who are high risk (see definition) for developing the disease.


The term “thriver” is used in the metastatic breast cancer (MBC) community to differentiate from Survivor. Survivor can imply that cancer is cured and they are no longer living with the disease. Those with MBC live with their cancer but can be thriving.


A tumour is a group of abnormal cells that forms when cells divide and multiply too quickly or don’t die when they should. Tumours can be benign (non-cancerous) or malignant (cancerous).


An ultrasound is a breast cancer screening method that uses sound waves to examine the tissues. It tends to be a better screening method for young women under 40, who’s breast density prevents tissues from showing up properly on a mammogram.

Values (patient values)

Patient values refers to what patients value when it comes to cancer treatment and how they measure quality of life (see definition).  

Washout Period

Washout period is a term used to describe the process where a patient in a clinical trial (see definition) is taken off a drug in order to give it time to leave their system.  


Xeloda is a cancer treatment often used for stage III colon cancer patients. However, it’s also often used to treat metastatic breast cancer (see definition) in women who’s situation hasn’t improved with the use of any other anti-cancer drugs. 

Young Women with Breast Cancer 

The Rethink definition of young refers to women at a specific stage of life when there are demands on family, friends, careers, education and fertility. Most of these women are pre-menopausal. Rethink believes that the advocacy work we do with young women helps to improve access and create change for all women.


Zoladex is a hormone therapy drug used to treat estrogen receptor-positive breast cancer (see definition) by halting the production of estrogen in the ovaries.   

For more terms and definitions, check out this online glossary.

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