Glossary of Terms

Introduction

Parts of this glossary have been taken or adapted from the National Cancer Institute’s Cancer Dictionary and the American Breast Cancer Society’s Breast Cancer Dictionary.

This glossary does not contain definitions of medications. To learn more about specific medications, visit the website of the National Cancer Institute.

Many thanks to the healthcare practitioners who reviewed portions of this glossary:

• Mechelle Barrick, RN, BSN, OCN, Greater Baltimore Medical Center
• Debra S. Copit, MD, Albert Einstein Medical Center
• Ann L. Honebrink, MD, Penn Health at Radnor
• Isabel I. Law, RN, South Carolina Comprehensive Breast Center
• Judith Macon, RN, MA, Suburban Hospital Cancer Program
• Suzanne McGettigan Bensman, MSN, CRNP, AOCN
• Lisa McGinty, RN, BSN, Abramson Cancer Center, University of Pennsylvania
• Maria Rocktashel, MSN, CRNP, Delaware Valley Surgical Associates
• Lynn M. Schuchter, MD, University of Pennsylvania Abramson Cancer Center
• Michele D. Stolper, Dana-Farber Cancer Institute
• Fionda N. Williams, RN, BSN, Baltimore City Cancer Program

Glossary

obese

Having an abnormally high, unhealthy amount of body fat.

objective improvement

An improvement that can be measured by the healthcare provider (for example, when a tumor shrinks or there are fewer breast cancer cells in the blood).

objective response

A measurable response.

observation

Closely monitoring a person's condition but withholding treatment until symptoms appear or change. Also called watchful waiting.

observational study

A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).

obstruction

Blockage of a passageway.

obtundation

Pronunciation: (ob-tun-DAY-shun)

A dulled or reduced level of alertness or consciousness.

occupational therapist

A health professional trained to help people who are ill or disabled learn to manage their daily activities.

off-label

Describes the legal use of a prescription drug to treat a disease or condition for which the drug has not been approved by the U.S. Food and Drug Administration.

omega-3 fatty acid

A type of fat obtained in the diet and involved in immunity.

omentectomy

Surgery to remove part or all of the omentum.

omentum

Pronunciation: (oh-MEN-tum)

A fold of the peritoneum (the thin tissue that lines the abdomen) that surrounds the stomach and other organs in the abdomen.

Ommaya reservoir

Pronunciation: (o-MY-a REZ-er-vwahr)

A device surgically placed under the scalp and used to deliver anticancer medication to the fluid surrounding the brain and spinal cord.

oncogene

A gene that normally directs cell growth. If altered, an oncogene can promote or allow the uncontrolled growth of cancer. Alterations can be inherited or caused by an environmental exposure to carcinogens. For example, HER2/neu is an oncogene.

oncologist

Pronunciation: (on-KOL-o-jist)

A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

oncology

The study of cancer.

oncology clinical nurse specialist

A registered nurse with a master's degree in oncology nursing who cares for people affected by breast cancer. Oncology clinical nurse specialists may prepare and provide treatment, monitor ongoing health, prescribe medications and give supportive care.

oncology nurse

A nurse who specializes in treating and caring for people who have cancer.

oncology pharmacy specialist

A person who works with an oncologist to prepare anticancer medication.

oncology social worker

A social worker with a master's degree who specializes in providing social services to people affected by breast cancer. Oncology social workers provide counseling, supply information on resources, help with financial concerns, work with family members, answer questions about housing and child care and help out with many non-medical related concerns of women and families affected by breast cancer.

onset of action

The length of time it takes for a medicine to start to work.

oophorectomy

Pronunciation: (o-o-for-EK-toe-mee)

Surgery to remove one or both ovaries. Because the ovaries are a primary source for estrogen in pre-menopausal women, some women affected by or at risk for breast cancer may have the option of oopherectomy to lower their risk for developing or recurrent disease.

open biopsy

A procedure in which a surgical incision (cut) is made through the skin to expose and remove tissues. The biopsy tissue is examined under a microscope by a pathologist. An open biopsy may be done in the doctor's office or in the hospital, and may use local anesthesia or general anesthesia. A lumpectomy to remove a breast tumor is a type of open biopsy.

open label study

A type of study in which both the health providers and the participants are aware of the medication or treatment being given.

operable

Describes a breast cancer that can be treated by surgery.

opiate

A medication used to treat pain. It contains opium or a substance made from opium (such as morphine).

opioid

A medication used to treat moderate to severe pain. Opioids are similar to opiates such as morphine and codeine, but they do not contain and are not made from opium.

opportunistic infection

An infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems.

oral

By or having to do with the mouth.

organ

A part of the body that performs a specific function. For example, the heart is an organ.

organism

A living thing, such as an animal, a plant, a bacterium, or a fungus.

osmolality

The concentration of particles dissolved in a fluid. The osmolality of serum can help diagnose several medical conditions such as dehydration, diabetes, and shock.

osmotic

Pronunciation: (ahz-MAH-tik)

Having to do with osmosis (the passage of a liquid through a membrane from a less concentrated solution to a more concentrated solution). This makes the concentrations in both solutions more equal.

osteitis deformans

A chronic condition in which both the breakdown and regrowth of bone are increased. Osteitis deformans occurs most frequently in the pelvic and leg bones, skull, and lower spine. It is most common in older individuals, and may lead to bone pain, deformities, and fractures. Also called Paget's disease of bone.

osteolytic

Causing the breakdown of bone.

osteonecrosis of the jaw

Also called "dead jaw," jaw necrosis. Painful exposed bone in the jaw. Women who undergo radiation or chemotherapy or who receive steroids as part of breast cancer treatment are at increased risk for this condition. Women who take bisphosphonates may also be at risk for jaw necrosis.

osteoporosis

Pronunciation: (OSS-tee-oh-pa-ROW-sis)

A condition that is characterized by a decrease in bone mass and density, causing bones to become fragile. Some breast cancer treatments put women at higher risk for developing osteoporosis.

OTC

Over-the-counter. A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen. Also called nonprescription.

ounce

A measure of weight (one-sixteenth pound) and volume (one-eighth cup).

outpatient

A person who visits a healthcare facility for diagnosis or treatment without spending the night. Sometimes called a day patient.

ovarian

Having to do with the ovaries, the female reproductive glands in which the ova (eggs) are formed. The ovaries are located in the pelvis, one on each side of the uterus.

ovarian ablation

Surgery, radiation therapy, or a medical treatment to stop the functioning of the ovaries. Also called ovarian suppression. Because the ovaries are a primary source for estrogen in pre-menopausal women, some women affected by or at risk for breast cancer may have the option of ovarian ablation to lower their risk for developing or recurrent disease.

ovarian cancer

Cancer that originates in the ovaries. Women who test positive for the BRCA1 or BRCA2 gene mutation are at higher risk than the general population for developing breast and ovarian cancer.

ovarian damage

Also called amenorrhea. Damage to the ovaries as a result of certain breast cancer treatments that may impact a woman's fertility, particularly women who are pre- and peri-menopausal.

ovarian epithelial cancer

Cancer that occurs in the cells lining the ovaries.

ovarian function

The normal work of the ovaries can be carried out. Pre- and peri-menopausal women may experiences changes to normal ovarian function as a side effect of certain breast cancer treatments. Tests for follicle-simulating hormone or FSH can measure whether the ovaries are functioning normally.

ovarian suppression

Surgery, radiation therapy, or a drug treatment to stop the functioning of the ovaries. Also called ovarian ablation. Because the ovaries are a primary source for estrogen in pre-menopausal women, some women affected by or at risk for breast cancer may have the option of ovarian suppression to lower their risk for developing or recurrent disease.

ovarian tissue

Tissue belonging to the ovary, fallopian tubes and other reproductive organs that function to produce cells that allow eggs to grow. Research is being conducted to see whether implanting ovarian tissue can help women at risk for losing fertility as a result of breast cancer treatment.

ovary

Pronunciation: (O-va-ree)

One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus. Ovaries are a primary source or estrogen in pre-menopausal women.

over-the-counter

OTC. A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen. Also called nonprescription.

overall survival

The percentage of participants in a study who have survived for a defined period of time. Usually reported as time since diagnosis or treatment. Also called the survival rate.

overexpress

An excess of a particular protein on the surface of a cell. For example, some breast cancers overexpress the HER2/neu protein. Knowing whether a breast cancer overexpresses this protein may help in understanding treatment options.

overweight

Being too heavy for one's height. Excess body weight can come from fat, muscle, bone, and/or water retention. Being overweight does not always mean being obese.

ovulation

Pronunciation: (ov-yoo-LA-shun)

The release of an egg from an ovary during the menstrual cycle.

oxidation

Process in which molecules are split to give products that have unpaired electrons.

oxidative metabolism

A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also known as aerobic respiration, cell respiration, or aerobic metabolism.

oxidative stress

A condition in which antioxidant levels are lower than normal. Antioxidant levels are usually measured in blood plasma.

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