accrual: The process of getting patients onto a clinical trial, or the number of patients planned for a given trial.

acquired resistance: The ability of a tumor to resist chemotherapy treatment following an initial response.

adenoma: A benign tumor made up of glandular tissue.

adenocarcinoma: A cancer that develops in gland-forming tissue. Most breast cancers are adenocarcinomas.

adjuvant chemotherapy: Anti-cancer drugs used in combination with surgery and/or radiation to destroy residual cancer cells to prevent or delay recurrence.

adjuvant therapy: Treatment that is given before there is any indication that the cancer has spread to prevent or delay the development of metastatic breast cancer administered after surgery and/or radiation.

AFP: Alpha fetoprotein, a tumor marker.

alopecia: Hair loss or thinning.

alternative therapy: Any non-traditional cancer treatment used instead of a traditional medical cancer treatment.

amenorrhea: Loss of menstrual periods.

anemia: Condition in which a decreased number of red blood cells may cause symptoms including tiredness, shortness of breath, and weakness.

aneuploid: Abnormal amount of DNA in a cell, can correlate with a worse cancer.

angiogenesis: The process of development of new blood vessels. In cancer, the development of blood vessels can feed tumors and allow them to grow, and drugs that block angiogenesis are being tested as cancer treatment.

anorexia: The loss of appetite.

antibody: Substance formed by the body to help defend it against infection.

antiemetic agent: A drug that prevents or controls nausea and vomiting.

antigen: A substance that causes the body to produce natural antibodies.

apoptosis: A genetically mediated series of events by means of which cells actively trigger their own destruction.

areola: The circular area around the nipple on the breast, typically darker than the rest of the breast.

arm: Any of the treatment groups in a randomized trial. Most randomized trials have two arms, but some have three or more.

aspiration: A technique for removing fluid from a cyst or cells from a mass, using a needle and syringe.

asymptomatic: Medical condition which is silent, has no symptoms.

atypical cell: Mild to moderately abnormal cell when viewed under the microscope, not malignant.

atypical hyperplasia: Cells that are both abnormal (atypical) and increased in number. Benign microscopic breast changes known as atypical hyperplasia may increase a woman’s risk of developing breast cancer.

autologous transplant: The reintroduction of cells, tissue or organ previously removed from an individual, back into the same individual with continued function after reintroduction.

axillary lymph nodes: Lymph nodes found in the armpit. Tumor in these nodes portends a high risk of recurrence.

basement membrane: A layer of cells that separate the epithelial cells and other tissue cells. Cancer invades this membrane and grows into adjacent tissue.

benign: Not cancerous.

bilateral: Involving both sides, such as both breasts.

biomarkers: Any of various biological or biochemical indicators that serve to detect exposures to carcinogenic processes or to predict carcinogenic disposition.

biopsy: The removal of a sample of abnormal tissue that is microscopically examined for cancer cells.

blind: A randomized trial is blind if the patient is not told which arm of the trial she is on.

blood cells: Minute structures produced in the bone marrow that circulate in the veins and arteries; they consist of red blood cells, white blood cells and platelets.

blood count: The number of red blood cells, white blood cells and platelets in a sample of blood.

bone density scan: Scan which measures the mineral content of bone and is used to detect osteoporosis.

bone marrow: The soft, sponge-like material inside some bones. Blood cells are produced in the bone marrow.

bone marrow transplant: A procedure in which physicians replace marrow destroyed by high doses of anti-cancer drugs or radiation. The replacement marrow may be taken from the patient before treatment or may be donated by another person. When the patient’s own marrow is used the procedure is called autologous bone marrow transplant.

bone scan: A picture of the bones using a radioactive dye that shows any injury, disease, or healing. This is a valuable test to determine if cancer has spread to the bone, if anticancer therapy has been successful, and if affected bony areas are healing.

BRCA1 and BRCA2: The principal genes that, when abnormal, or mutated, indicate an inherited susceptibility to breast and ovarian cancers; accounting for 80-90% of all inherited cases of breast and the majority of inherited ovarian cancers.

breast cancer: The uncontrolled growth of abnormal breast cells. This is one of the most common kinds of cancer in women. Early detection through regular breast self-exams and a regular program of mammography and physical exams shows excellent results in combating it

breast-conserving therapy: A treatment for breast cancer in which the breast is preserved, it usually consists of segmental mastectomy , lumpectomy and radiation therapy.

breast density: Term describing the proportion of fat to fibrous tissue. Mammography is more effective when screening breasts of less density.

breast disease: Any one of number of abnormalities of the breast, either non-cancerous-fibroadenoma, fibrocystic disease, mammary duct ectasia, ductal papilloma, fat necrosis and others; or cancerous-breast cancerous.

breast implant: Special type of prosthesis filled with saline or silicone. It is surgically placed on the chest wall to form a breast mound after mastectomy.

breast lumps: Any swelling or unusual lump or hardness in the breast. An indication of breast disease and a reason to see your doctor. Most are not cancerous.

BSE: Breast self-exam, manual self examination of the breast.

calcifications: Calcium deposits in the breast which can be either benign or malignant.

cancer: General term for a large group of diseases in which abnormal cells divide without control.

carcinoma: Cancer that begins from cells that line glands and in the lining of internal organs.

carcinoma in situ (CIS): An abnormal growth of cells that stays within the area in which it started and has not spread to other parts of the body.

CEA: Carcinoembryonic antigen, a blood tumor marker that, when elevated, can indicate the presence of cancer.

cervical nodes: Lymph nodes in the neck.

chemoprevention: The use of drugs or vitamins to prevent cancer in people who have precancerous conditions or a high risk of cancer, or to prevent the recurrence of cancer in people who already have been treated for it.

chemotherapy: A treatment for cancer that works by killing all rapidly reproducing cells, but also has side effects on normal cells.

chronic: Persisting over a long period of time.

clean margin: A boundary of normal tissue surrounding the cancer in a surgically excised tissue.

clinical breast exam: A breast exam performed by a trained medial professional to check for any physical changes or lumps in the breast.

clinical trials: Randomized and controlled research studies involving large groups of patients. Designed to answer questions regarding the optimal treatment of disease.

CMF chemotherapy: Three drugs, cyclophosphamide, methotrexate, and 5 fluorouracil, commonly used to treat breast cancer.

comedo: Type of DCIS where dead cells and debris fill the duct. This type of DCIS has a higher recurrence risk.

complementary and alternative medicine (CAM): Treatment of health care problems with the use of acupuncture, homeopathy and herbal therapy. These treatments can include guided imagery, meditation, massage, therapeutic touch, etc., and are often combined with standard therapy.

complete response: All detectable cancer is gone after treatment. This is not the same as a cure, as there may still remain some cancer too small to detect.

contracture: Formation of a thick scar tissue; in the breast a contracture can form around an implant.

control group: The arm of a randomized trial which gets the standard treatment or no treatment.

core biopsy: Removal of a sample of tissue, using a wide needle, to see if cancer cells are present.

CT scan: “Computed tomography scan” in which X-rays are used to create cross-sectional pictures of the body.

cyst: A fluid-filled sac, usually benign.

DNA (deoxyribonucleic acid): A large molecule that carries the genetic information that cells need to replicate and to produce proteins.

diagnostic mammogram: A diagnostic mammogram is used to evaluate a woman with a breast problem/symptom or an abnormal finding on a screening mammogram.

diagnostic ultrasound: Ultrasound is another way of looking inside the breast by using sound waves instead of x-rays. It can distinguish a liquid-filled cyst from a solid mass, and it can help to distinguish the difference between normal and abnormal breast lumps.

differentiated: Clearly defined. Differentiated tumor cells are similar in appearance to normal cells, and usually carry a better prognosis.

diploid: Normal amount of DNA in a cell, can correlate with a better prognosis.

disease free survival: Time the patient survives without any detectable cancer after initial treatment.

dissection: Removal of specific tissue (breast lump), leaving surrounding tissues in place.

distant recurrence: Reappearance of cancer at another site.

dose limiting toxicity: Side effects that are severe enough to prevent giving more of the treatment in a clinical trial.

double-blind: A research design in which neither the investigator or the patient knows whether the patient is given a new drug or current standard of care until it is time to analyze the results.

ductal carcinoma in situ (DCIS): Cancer cells that develop from the lining of the milk duct but are confined to the ducts of the breast. DCIS is considered to be a precursor to invasive cancer, and almost never spreads beyond the breast.

ductal papillomas: A non-cancerous breast disease that may cause a bloody nipple discharge.

ECOG status: The Eastern Cooperative Oncology Group scale for measuring patient performance status on a scale from 0 (no symptoms) to 4 (completely bedridden).

end point: The goal of a clinical trial, what it is trying to measure.

enzyme: A protein molecule that accelerates chemical reactions in cells or organisms.

erythema: Redness of the skin.

estrogen: A type of female sex hormone produced by ovaries, adrenal glands, placenta, and fat.

estrogen receptor (ER) negative: breast cancer cells that do not contain estrogen receptors. Receptors are cites on the cell to which estrogen attaches, promoting cancer cell growth. Estrogen receptor negative cells do not have the receptors necessary to bind with hormone therapy to block the flow of estrogen to the cell. Hormone therapy works by keeping cancer cells from getting the hormones they need to grow.

estrogen receptor (ER) test: test done on tumor tissue to determine if a tumor is sensitive to estrogen (ER positive), and thus whether hormone therapy may be effective.

evaluable disease: A tumor or tumors which cannot be measured accurately but are definitely present on an x-ray or by examination.

excisional biopsy: Tumor or mass is removed from the breast, and cut into thin sections that are microscopically studied to see if cancer cells are present.

experimental group: The arm of a randomized trial which gets the new or experimental treatment.

fat necrosis: A non-cancerous breast disease caused by trauma or injury.

fibroadenoma: A benign tumor composed of fibrous tissue.

fibrocystic breast disease: Term used to describe a benign breast condition.

fibrocystic changes: A non-cancerous breast condition, resulting in painful cysts or lumpy breast.

fixation: Attachment of tumors to deeper tissues. Associated with more advanced disease.

FNA (fine needle aspiration): Biopsy in which cells are removed from a lump by needle and syringe, and then tested to see if cancer cells are present.

frozen section: A sliver of frozen biopsy tissue, used for immediate diagnosis at the time of surgery.

galactocele: Milk filled cyst

gene: Segment of the DNA molecule and the fundamental biological unit of heredity. They contain chemical information to make proteins, control inherited traits, and influence the activity of other genes.

gene markers: Landmarks for a target gene, either detectable traits that are inherited along with the gene or distinctive segments of DNA.

genotype: The entire genetic makeup of an organism.

gluteal musculocutaneous free flap: One of the techniques for breast reconstruction which uses the patient’s own tissues rather than an implant.

grade: In the context of clinical trials, refers to a numeric scale rating the severity of toxicity from treatment. Also see histologic grade below.

HER2/neu: Human oncogene found to be in elevated amounts in some women with breast cancer.

histologic grade: Subjective microscopic assessment of degree of departure from normal tissue structure. High grade implies a more aggressive tumor.

hormone: Any one of a group of chemicals produced by the body’s glandular tissues. They are transported by the blood stream. These substances interact with one another and are an essential part of the control of vital bodily functions.

hormone (endocrine) therapy: Treatment to block your body’s natural hormones from reaching any remaining breast cancer cells.

hormone receptors: Proteins on the cell surface which admit substances to that cell. These substances may be hormones, drugs, or toxins similar in structure to the receptor’s target hormone.

hormone therapy: A treatment for cancer that works by removing, blocking or adding hormones.

hyperplasia: Condition in which there is an abnormal increase in the number of cells in a tissue.

immunotherapy: Genetically reengineered genes are used to boost the immune system.It is designed to act only on the cancer cells, so there is no adverse effect on normal cells, thus there are no adverse side effects.

implant: A silicone bag filled with either saline or silicone gel used in reconstructive surgery to create a breast shape.

incisional biopsy: Removes only a portion of the tumor for pathology to examine, generally reserved for larger tumors.

infiltrating cancer: Cancer that has grown beyond its site of origin into neighboring tissue. Does not imply that the cancer has spread outside the breast.

inflammatory breast cancer: Uncommon type of cancer in which cancer cells block the lymph vessels of the breast. Blockage causes the breast to become red, swollen and warm with a dimpled (like an orange) appearance to the skin.

informed consent: The process by which a person learns about and understands the purpose and aspects of a clinical trial before voluntarily deciding whether or not to participate.

infusion: Delivering fluids or medications into the bloodstream (usually by vein) over a period of time.

in situ: A term that refers to cancers that have not grown beyond their original site. This usually implies non-invasive tumor.

Institutional Review Board (IRB): A committee of medical specialists, lawyers, ethicists, community representatives, and clergy approved by the federal government to review, modify, approve, or disapprove the research trial. All clinical trials must be approved by an IRB.

intraductal papilloma: A small benign growth that projects into a breast duct and can cause bleeding from the nipple.

invasive: Tumor which grows into and destroys healthy tissue; same as infiltrating.

Karnofsky status: A performance status scale which rates the severity of symptoms and degree of disability from 100% (no symptoms) to 0% (dead).

latissimus flap: Flap of skin and muscle taken from the back and used for reconstruction after mastectomy or partial mastectomy.

lesion: Any focal abnormal area in the body. Can be used to describe a benign or malignant growth.

leukopenia: A drop in the number of circulating white cells in the body, making the individual more susceptible to infection.

linkage: Genes are said to be linked when they reside close together on the same chromosome.

lipoma: A benign fatty tumor which forms a lump.

lobules: Working units of the breast capable of producing milk.

lobular carcinoma in situ (LCIS): Cancer cells that develop from the lining of the lobules in the breast. LCIS is not considered to be a precursor to cancer, but it is a marker of high risk.

local recurrence : The return of breast cancer in or near the primary site.

local therapy: Radiation therapy or topical therapy (like 5FU), only the area of involvement is affected by the treatment.

localized biopsy (wire or needle): Uses mammography or ultrasound to aid in the biopsy of abnormalities that can be seen on a mammogram or ultrasound, but cannot be felt by the surgeon.

lumpectomy: The surgical removal of the breast lump and a margin of healthy breast tissue.

lymphatic system: The tissues and organs (including the bone marrow, spleen, thymus and lymph nodes) that produce and store cells that fight infection and diseases. The channels that carry the lymph fluid are also part of this system.

lymphedema: Swelling of the arm or hand caused by buildup of lymph usually after an axillary lymph node dissection.

lymph node: Glands found throughout the body along lymphatic channels which defend the body from bacteria or other foreign invaders. If cancer cells are found in the lymph nodes, they are an indication that the cancer may have spread beyond the breast.

lymphoma: A cancer of the lymphatic system. Lymphomas are differentiated by the type of cell that is involved in the makeup of the tumor.

magnetic resonance imaging (MRI): A technique that uses a powerful magnet linked to a computer to create detailed pictures of areas inside the body.

malignant: Cancerous.

mammary glands: The breast glands that form and carry milk to the nipples during pregnancy and lactation.

mammogram: A low dose x-ray of the breast.

mastectomy: The surgical removal of the breast. Simple mastectomy involves the removal of the entire breast; radical mastectomy involves the removal of the entire breast along with underlying muscle and lymph nodes of the armpit.

mastitis: Infection of the breast, sometimes used loosely to refer to any inflammation in the breast.

mastodynia: Pain in the breast.

maximum tolerated dose (MTD): The highest dose of a drug or other treatment that most people can safely withstand.

measurable disease: Tumors whose size can be clearly measured in two dimensions. Some clinical trials require measurable disease.

mediastinum: The space in the chest between the pleural sacs of the lungs that contains all the viscera of the chest except the lungs and pleurae.

medical oncologist: Physician who treats cancer with the use of drugs and hormones.

menopause: Time when a woman’s ovaries cease producing estrogen and progesterone. One of the many symptoms is the cessation of menstruation.

menstruation: The monthly discharge, during a woman’s reproductive years, of blood and tissue from the uterus.

metastasis: The spread of cancer beyond the primary site of the cancer, and beyond the axillary nodes.

microcalcifications: Small deposits of calcium in the breast, which can show up on a mammogram. Certain patterns of microcalcifications are sometimes a sign of breast cancer.

micrometastases: Microscopic and as yet undetectable but presumed spread of tumor cells to other organs.

mitotic rate: Rate at which cell division occurs.

modified radical mastectomy: Surgery to remove the entire breast, nipple and axillary lymph nodes.

morbidity: Symptoms of illness produced by disease or treatment.

myeloma: A malignant tumor of the bone marrow associated with the production of abnormal proteins.

myocutaneous flap: Skin, muscle and other tissue surgically moved from one part of the body to reconstruct the breast which has been removed due to cancer.

needle aspiration: A process for testing a lump to determine whether it is cystic or not.

needle localization: A technique used to precisely locate a breast abnormality for a more detailed X-ray examination of the area.

neoadjuvant therapy: Chemotherapy given before surgery to shrink a cancer.

neuropathy: Disease or abnormality of the nervous system.

noninvasive: Self contained, not growing into or destroying healthy tissue.

OCN: Oncology certified nurse.

oncology: The study and treatment of cancer. Doctors who specialize in oncology are called oncologists.

oncogene: A gene that promotes the growth of cancer.

oophorectomy: Surgical removal of the ovaries.

osteoporosis: Softening of the bones, or loss of mineral content, that occurs with age in some people.

palliative: An alleviating treatment that can give relief from symptoms, but is not a cure for a disease.

Pap smear: A test to detect cancer of the cervix.

partial response: A decrease in the total cross sectional area of all measurable tumors of at least 50% but less that 100%.

pathologist: Physician who identifies diseases by studying tissue or cells under a microscope.

pathology: The science or study of the origin, nature, and course of diseases.

pathology report: A pathology report is a document that contains the diagnosis determined by examining cells and tissues under a microscope. The report may also contain information about the size, shape, and appearance of a specimen as it looks to the naked eye.

pedigree: A family history in diagram form showing the family members (males as squares, females as circles) and their relationships to individuals with a certain disease.

peripheral neuropathy: A disease or degenerative state of the peripheral nerves in which motor, sensory, or vasomotor nerve fibers may be affected and which is marked by muscle weakness and atrophy, pain, and numbness.

phase: Clinical trials are carried out in these sequential steps. Phases I, II, and III are designed to find out different information. Patients may be eligible for studies in different phases depending on their condition, type and stage of cancer, and what therapy they have already had.

phenotype: The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

photosensitivity: Extreme sensitivity to the sun, leaving the patient prone to sunburns. This can be a side effect of some cancer drugs and radiation.

placebo: An inactive substance or treatment given to patients in a study which has been created to resemble the active treatment.

ploidy: Degree of repetition of the basic number of chromosomes.

predictive gene tests: Gene testing to identify abnormalities that may cause a person to be vulnerable to certain diseases or disorders.

primary tumor: The original site of a cancer. Breast cancer that has spread to the bone is still called breast cancer.

progesterone: One of the female hormones produced by the ovaries.

progesterone receptor (PR) test: A test that determines if breast cancer is sensitive to hormonal therapy.

prognosis: A prediction about the possible outcome of a disease.

progressive disease: Disease is getting worse as documented by tests showing that tumors are growing or that new tumors are appearing.

prosthesis: an external breast form that can be used after a mastectomy

protocol: Research designed to answer a hypothesis; often involve testing a specific new treatment under controlled conditions.

radiation oncologist: Physician who uses radiation to treat cancer or its symptoms.

radiation therapy (radiotherapy): treatment using high energy x-rays to destroy cancer cells

radiologist: Physician who uses X-rays, ultrasound, MRI, etc. to aid in diagnosis.

randomized: Assignment to a clinical treatment arm by chance.

receptor: a specific location in a cancer cell that attracts hormones to attach to it in order to promote growth

reconstructive surgery: a procedure using plastic surgery to recreate a breast

recurrence: Return of cancer after its apparent complete disappearance.

RBC: Red blood count or number of red blood cells seen in a blood sample.

regional recurrence: Reappearance of cancer near the original site.

remission: Complete or partial disappearance of the signs and symptoms of disease (cancer).

risk factor: Anything that increases a person’s chances of developing cancer, for example, smoking and lung cancer.

S-phase: Measure of number of cells dividing DNA at any one time. A higher number usually indicates a more aggressive tumor.

sarcoma: A malignant tumor of muscles or connective tissue such as bone and cartilage.

screening mammogram: A screening mammogram is an x-ray of the breast used to detect breast changes in women who have no signs of breast cancer. It usually involves two x-ray of each breast. Using a mammogram, it is possible to detect a tumor that cannot be felt.

sentinel node: First node to which cancer cells migrate. Tumor cells on the node can be visualized by the use of dyes or radiographic techniques, and this experimental technique can eliminate the need for a complete axillary node dissection.

side effects: Symptoms or medical problems due to drugs used for disease treatment.

stage: Refers to the extent of cancer and is determined by the tumor size and whether it has spread to lymph nodes or other distant sites around the body.

stages of cancer: A numbering system (from 0 to 4) that tells doctors how advanced a specific breast cancer may be in order to determine appropriate treatment options.  Learn more about stages of breast cancer.

surgical oncologist: Surgeon who specializes in treating cancer.

systemic therapy: Taken intravenously or orally, goes through the body to attack cancer cells, or to lower the risk of recurrence after surgery.

TNM system: Classification based on T (tumor size), N (lymph node involvement), and M (presence or absence of metastatic spread). Various TNM combinations are collected onto staging groups based on similar clinical performance.

total mastectomy: Surgery to remove the entire breast including the nipple, but not the axillary lymph nodes.

toxicity: Side effects.

tumor: an abnormal mass of tissue.

tumor suppressor genes: Normally, these genes restrict cell growth, but when missing or inactivated by mutation, they permit cells to grow without restraint.

ultrasound: A sound wave imaging technique used to examine a part of the body. It is sometimes used to further evaluate a breast lump or other abnormality seen on a mammogram.

WBC: White blood count; the number of white blood cells seen in a blood sample. These are important in resistance to infections.

x-ray: Low doses of this type of radiation that penetrates tissue, are used to diagnose disease, high doses are used to treat cancer.


For more cancer terms visit  Learn about drugs approved for breast cancer treatment.