A

Adolescence: the period of physical and psychological development from the onset of puberty to adulthood, consisting mainly of the teenage years. 

Alkylphenols: a family of organic compounds used in the production of detergents, plastics and some pesticides. They tend to persist in the environment and can have estrogen-like properties. 

Areola: the dark pigmented area of the breast that surrounds the nipple. 

Aromatase: an enzyme that helps to produce estrogen in the body. After menopause, aromatase is used to produce estrogen in a woman’s fat and other tissues, not in the ovaries. Aromatase inhibitors are a type of hormone therapy that is used to treat some breast cancers. It works by blocking the ability of aromatase to produce estrogen. This helps to slow the growth of estrogen-sensitive breast cancer.  

Aspiration biopsy: the removal of tissue or fluid from a lump or cyst with a needle and syringe. (See also biopsy.) 

Asymmetry: an area that is found to be not identical in both breasts (such as tissue density).   

Asymptomatic: to be without noticeable signs or symptoms of a disease. 

B

Benign: not cancerous. This is also referred to as non-malignant. 

BRCA1: a gene which, when damaged (mutated), places the woman at greater risk of developing breast and/or ovarian cancer, compared with women who do not have the mutation.  

BRCA 2: a gene which, when damaged (mutated), places the woman at greater risk of developing breast and/or ovarian cancer, compared with women who do not have the mutation.  

Bilateral: affecting both sides of the body. 

Biopsy: a procedure in which tissue samples are removed from the body for examination under a microscope to determine if cancer or other abnormal cells are present. 

Bisphenol A (BPA): an organic compound used to make polycarbonate plastic and epoxy resins, along with other applications. Research has found that exposure to BPA can disrupt hormone levels in the body. In September 2010, Canada became the first country to declare BPA a toxic substance. Canada and Europe have banned BPA's use in baby bottles. (See also xenoestrogrens.) 

Body Mass Index (BMI): a measure of a person’s weight in relation to their height. This is one way of assessing body weight. 

Breast implant: surgically implanted artificial breasts that are made out of silicone or saline. Women who have had breast cancer surgery by mastectomy may choose to have implants to reconstruct the breast. 

C 

Carcinogen: a substance that causes cancer or helps cancer to grow. Tobacco and alcohol (ethynol) are examples of carcinogens. 

Carcinogenesis: the process of how cancers start and progress. This process usually takes place over many years and is marked by progressive genetic changes (mutations) and tissue damage.

Carcinoma: a malignant (cancerous) tumor that begins in the lining layer (epithelial cells) of organs. 

Cell: the basic structural and functional unit of all organisms. 

Chemoprevention: the use of drugs or other agents to try to prevent or delay the onset of cancer or its recurrence.  

Clinical breast exam (CBE): a physical examination of the breasts by a health-care provider. 

Clinical trials: In cancer research, there are two main types of research study: experimental and observational. One of the most common types of experimental studies is the randomized clinical trial (RCT).   

Cyst: a fluid-filled sac that is usually benign (non-cancerous). The fluid may be removed for analysis. 

D 

Dense breasts (breast density): Dense breasts have less fat and more glandular and connective tissue. A woman’s breast density depends on her age and genetic factors. Women who have gone through menopause tend to have less breast density. Breast density is a risk factor for breast cancer. Having “dense breasts” is a clinical diagnosis that can only be assessed by mammography.
 

Detection: in terms of health, this means finding disease. Earlier detection means finding disease earlier, when it is small and has not spread to other parts of the body. The earlier detection of disease often leads to better and less invasive treatment options.  

Digital mammography: a low-dose X-ray similar to screen-film mammography, equipped with a digital receptor and a computer instead of film. 

Dimpling: a pucker or indentation of the skin on the breast. 

Discharge (nipple): fluid from the nipple, that is not breast milk or related to breastfeeding. Nipple discharge should be evaluated by a health care provider. 

DNA: short for Deoxyribonucleic acid. DNA is found in the cells of our bodies. It contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. Your DNA contains genetic information that is unique to you. 

Duct: A hollow passage for gland secretions. There are ducts in the female and male breast.  

E 

Endocrine disruptors: substances that mimic natural hormones in the body and may disrupt how the endocrine system works. Some pesticides, for example, are thought to be endocrine disruptors. Endocrine disruptors are also known as hormone disruptors. 

Endocrine system: the body's system of glands, each of which secretes a hormone that regulates the body.   

Estrogen: a female sex hormone that is produced mainly in the ovaries. A woman’s levels of estrogen fluctuate throughout her life. Estrogen has been linked to the development of breast cancer and may promote the growth of cancer cells. 

F

False negative: some test results miss cancer. This is referred to as a “false negative” result. This type of screening result is rare. Regular screening at specific time intervals is the best way to overcome this limitation.  

False positive: some test results show signs of cancer that are ruled out when further testing is done. This is referred to as a “false positive” result. About one in ten women may be called back for more testing after their mammogram. Most women who require additional testing will not have breast cancer.
 

Fibroadenoma: a benign growth originating in the glandular tissue of the breast.   

Fibrocystic change: or fibrocystic disease. This describes a type of benign (non-cancerous) breast change. 

Fragrance (or parfum): a mixture of aroma compounds, fixatives and solvents used to give the human body, animals, objects and living spaces a scent. Some synthetic compounds found in fragrances cause inflammation, headaches, dizziness or nausea in people who are sensitive to them. 

G 

Galactorrhea: sudden flow of milk from the breast, that is not associated with childbirth or nursing. 

Gene: a segment of DNA that contains hereditary information.  

Genetic: related to or caused by the genes. (See also gene, hereditary.) 

Genetic counsellor: a health care provider with specialized training and experience in the areas of medical genetics and counselling.Glands: Organs used locally or elsewhere in the body. 

H 

HER-2-neu: Cells have many different proteins on their surface called receptors. HER-2 is a type of naturally occurring receptor. In normal cells, HER-2 receptors are thought to be involved in cell growth and reproduction. In some breast cancers, there are too many HER-2 receptors and they speed up cancer cell growth.  HER-2 therapy is used to treat some breast cancers by targeting receptors that stimulate breast cancer growth.
 

Hereditary: a trait, for example eye colour, that is transmitted genetically from one generation to the next. Some genetic mutations are inherited, for example mutations of the BRCA 1 or BRCA 2 genes that lead to a strong increase in the risk of breast cancer. (See also: genetic.) 

Hereditary breast cancer: research shows that approximately 5 to 10 per cent of breast cancers are hereditary. Families that show signs of hereditary breast cancer include the following:

• Family members diagnosed with breast cancer before age 35.
• Family members diagnosed with ovarian cancer at any age.
• Multiple family members diagnosed with breast or ovarian cancer.
  A male family member with breast cancer.
• Family members who have been diagnosed with breast cancer in both breasts or with breast and ovarian cancer.
• Ashkenazi Jewish ancestry  

Hormone disruptors: substances that mimic natural hormones in the body and may disrupt how the endocrine system works. Some pesticides, for example, are thought to be endocrine disruptors. Hormone disruptors are also known as endocrine disruptors. 

Hormone replacement therapy (HRT): is a hormone treatment intended for women who have reached the age of menopause, to reduce its symptoms. It involves taking small doses of estrogen and progesterone (combined) or just estrogen alone. (See also hormone, estrogen, progesterone.) 

I - J

Implants: surgically implanted artificial breasts that are made out of silicone or saline. Women who have had breast cancer surgery by mastectomy may choose to have implants to reconstruct the breast. 

Immunotherapy: a form of biological therapy that uses treatment to stimulate the immune system or restore its ability to fight infection and disease, including cancer. This form of therapy is also used sometimes to help reduce the side effects of cancer treatment. 
 

Incidence: the number of newly diagnosed cases of a disease during a specific time period.  

Inverted nipple: a condition in which the nipple is tucked into the areola. 

K 

Klinefelter syndrome: A genetic condition in men that increases the risk of breast cancer. Men with Klinefelter syndrome may have larger than normal breasts, a lack of facial or body hair, a rounded body type, and small testicles. The condition is caused when a man’s DNA has one or more extra X chromosomes.
 

L

Lactation: production of milk in the breast. 

Latency: the time from the start of a disease to when its symptoms show. A latent condition is present in the body but does not cause symptoms to show in the person.

Cancer is described as a disease with a long latency period: it usually takes many years from the time the cancer starts to develop to when symptoms show. This is why screening is such an important earlier detection tool – it is able to detect cancer before the person may feel any signs or symptoms of the disease.

Lesion: an area of abnormal tissue in the body. Testing may show that the lesion is benign (not cancer) or malignant (cancer). 

Lobules: the glandular clusters at the ends of breast ducts that are capable of producing milk. 

Lump: a mass that can be found in the breast or elsewhere in the body. This can also be called a nodule. 

Lumpectomy: surgery to remove a breast tumor and a small margin of surrounding normal tissue. 

Lymphatic system: a network of vessels that transports lymph fluid, a clear fluid that comes from your blood and bathes the tissues. It contains water, protein and minerals and white blood cells. The lymph passes through a series of filters, the lymph nodes, before rejoining the bloodstream. 

M

Malignant: cancerous. 

Mammogram (also called mammography): a low-dose X-ray of the breast. It is used to take images of the breasts and is an important screening tool for the earlier detection of breast cancer.Mastectomy: surgery to remove all or part of the breast and sometimes other tissue. 

Menarche: a woman’s first menstrual period. Early menarche (before age 12) is a risk factor for breast cancer. 

Menopause: a natural part of a woman's aging process, when the ovaries start to make less estrogen and progesterone and the menstrual periods stop. This change typically occurs between the late 40s and mid-to-late 50s. 

Metastatic (metastases):  the spread of cancer from its original (primary) location to another part of the body. A tumour that is formed by cancer cells that have spread to another part of the body is called a “metastatic tumour” or a “metastasis.”

When breast cancer spreads, or metastasizes, the most common sites include the bones, liver, brain and lungs. Once it has spread to other parts of the body, breast cancer is no longer considered curable. However it can still be treated and many people live with metastatic breast cancer for a long time.
 

N

Nodule: A small, solid lump that can be located by touch. This can also be called a mass.  

O

Observational study: In cancer research, there are two main types of research study: experimental and observational. In an observational study, the researchers observe groups of people engaged in their normal activities, without an intervention controlled by researchers. There are different types of observational studies:

• Case-control studies. These compare two groups of people, such as those who have cancer (the case) and those who do not (the control). 

• Cohort studies. These study events as they occur. The researchers monitor a group of people for a long time and track, for example, any new cases of cancer. This approach is often used to study whether certain nutrients or lifestyle behaviours could reduce the risk of cancer. 

• Case-series studies. These studies use detailed descriptions of a patient's diagnosis and treatment history, called case reports. If many patients are given a similar treatment, each case report may be combined to form a case series. 

• Cross-sectional studies. These studies examine the relationship between diseases and other factors (such as exposures or behaviours) within a specific population at one point in time.

• Meta-analyses. These studies combine the results of several studies on the same topic. By combining studies, a meta-analysis has the ability to find trends that may not be apparent in smaller studies. 

Oestrogen: see estrogen.  

Oncologist: a doctor or surgeon who specializes in treating cancer. A medical oncologist specializes in drug therapy (chemotherapy) for cancer. A radiation oncologist specializes in treating cancer with radiation.
 

P 

Paget’s disease: a rare form of breast cancer that begins in the milk passages (ducts) and spreads to the skin of the nipple and areola. The affected skin may appear crusted, scaly, red, or oozing.    

Papilloma: a benign (non-cancerous), wart-like growth of the lining of a breast duct. Sometimes these can cause a bloody nipple discharge. If you experience this, discuss it with a health care provider. 

Parabens: a class of chemicals widely used in the cosmetic, pharmaceutical, and food industries. Parabens are controversial because they have the ability to mimic estrogen. They have been found in low concentrations in breast cancer tumours. The link between parabens and cancer is not conclusive and more research is needed in this area. 

Paresthesia: a sensation of numbness, tingling, pins and needles, or pricking that is usually felt on the skin. Paresthesia is one of the possible side effects of lymph node removal. Breast cancer surgery may include the removal of lymph nodes for further examination in a lab, to see if the cancer has spread (metastasized) beyond the breast. 

Parfum: a mixture of aroma compounds, fixatives and solvents used to give the human body, animals, objects and living spaces a scent. Some synthetic compounds found in fragrances cause inflammation, headaches, dizziness or nausea in people who are sensitive to them.  

Phthalates: derived from phthalic acid (an organic compound used in the manufacture of dyes, perfumes, pharmaceuticals and synthetic fibre) and mainly used as plasticizers (substances added to plastics to increase their flexibility and longevity). They are being phased out of many products in Canada, the US and Europe over potential health concerns.  

Placental extracts: Controversial ingredient found in some cosmetics and beauty products. These extracts are derived from human or animal placenta: organs that develop in female mammals during pregnancy to provide nourishment to the fetus. The placenta produces progesterone and estrogen, and there is some concern they may act as hormone disruptors when absorbed through the skin. 

Precautionary approach: When we face scientific uncertainty, we have options. We can choose to do nothing and wait for more research to be done. Or, if we think there is potential for harm, we can choose to take preventive action now – this is what’s known as the precautionary principle.

The precautionary principle offers a way to understand inconclusive scientific evidence about chemical risks to our health and the environment. This approach puts health, well-being and the environment first, even though science may not yet have all the answers.

Wingspread Statement on the Precautionary Principle, January 1998: "When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically. In this context the proponent of an activity, rather than the public, should bear the burden of proof. The process of applying the precautionary principle must be open, informed and democratic and must include potentially affected parties. It must also involve an examination of the full range of alternatives, including no action." 

Progesterone: a female sex hormone released by the ovaries during the woman’s menstrual cycle to prepare the uterus for pregnancy and stimulate milk production in the breast. It is also one of the synthetic hormones used in hormone replacement therapy. (See also HRT, hormone.) 

Proliferative: growing or increasing in number. In the human body, cells proliferate or increase by a process called cell division. The same process of division happens in normal cells and in cancer cells. This is how cancer cells grow and spread.
 

Q

Qualitative research: This type of research tries to provide a picture of the context and complexity of experience, to get at explanations of “how” and “why” things happen. It focuses on the stories that people tell about their experiences, for example of breast cancer treatment. Sources of qualitative research data include individual interviews, focus or group interviews, case studies and observation.  

Quantitative research: Research based on statistics is usually called “quantitative” because it focuses on counting things. The most basic information about cancer comes from statistics on cancer incidence (rate of new cases) and mortality (death rate). Cancer incidence rates are usually specified by gender and age.

R

Radiation therapist: a licensed health care provider who gives radiation therapy to cancer patients. 

Radioactive: describes something that gives off radiation. Radiation is energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas and medical X-rays. 

Radiologist: A doctor who specializes in reading tests such as ultrasounds and X-rays. A radiologist may also perform core biopsies and use imaging techniques to guide cancer treatment.

Recurrence: cancer that returns after treatment.

Risk factor: Anything that increases a person’s chance of developing a disease, such as cancer.

S 

Screening: the search for diseases such as breast cancer in people without symptoms. Mammography is an important tool for breast cancer screening and earlier detection. (See also detection, mammogram.) 

Staging: Breast cancer is sometimes classified as early, locally advanced or metastatic.

Early breast cancer is still in the breast tissue. Locally advanced breast cancer refers to a cancer larger than 5cm across or one that has spread from the breast to tissues or lymph nodes near the breast, such as the chest and armpit. Metastatic breast cancer, also known as secondary cancer, has spread from the breast to distant tissues or organs in the body.  

Synthetic chemicals: compounds not found in nature, but developed in a lab. Many environmental health advocates believe that synthetic chemicals may play a role in the development of cancer.

T 

Tamoxifen: a drug blocks the effects of estrogen on many organs, such as the breast. 

Thermography: (Also called thermal imaging or infrared imaging) is a computerized imaging tool that measures heat distribution at the surface of the breast. While thermography may be appealing to some women because it is a pain-free exam, scientific research has shown that thermography is not reliable for detecting breast cancer. 

Thickening: an area of skin that thickens or swells. This is a sign to look for on the breasts as part of being breast aware. 

Tumour: an abnormal mass of tissue that occurs when cells divide more than they should or do not die when they should. Tumours may be benign (not cancer) or malignant (cancer). A tumour is also called a neoplasm.  

U - Z 

Xenoestrogens: industrially made compounds, found in pesticides, fuels and plastics, that are thought to mimic estrogen or alter the natural effects of estrogen. (See also bisphenol A)

More Information:

Resources

About breast health

About breast cancer