Harold C. Simmons Comprehensive Cancer Center

Cancer-related Terms Explained

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A cancer diagnosis can be overwhelming, especially when there are new words to learn. This can be particularly confusing for children. If you encounter new terms and aren’t sure how to explain them to your children, ask your doctor, nurse, or other health care team member at UT Southwestern for guidance.

The following are simple definitions of terms you might hear during your diagnosis and treatment of cancer. You might find it useful to share this list with your children as it applies to your situation.

A condition or an illness that develops suddenly. The opposite is "chronic."

Adjuvant therapy
Treatment used to kill remaining cancer cells left behind after the main treatment. Examples include radiotherapy, chemotherapy, and hormone therapy.

Advance directive
A written statement about what kind of medical treatment someone wants to receive if they’re unable to make decisions.

Special proteins that travel through the bloodstream to fight an infection.

A growth that is not cancer. Unlike cancerous tumors, benign tumors don't spread to other parts of the body.

A procedure where doctors remove cells from a person’s body and examine them closely to see whether it’s cancer.

Bone marrow
A type of tissue found in certain bones that make blood cells.

A type of disease where cells grow out of control, divide, and usually develop into a tumor. Cancer is not contagious – you can’t catch it from someone who has it.

Drugs that are used to kill cancer cells. Chemo may cause people to lose their hair, feel sick, and become tired. 

A long-term condition or illness that may not have a cure. The opposite is "acute."

Clinical trials
Research studies that test new treatments for disease. The goal is to find new safe and effective ways to treat patients.

Complementary and alternative medicine (CAM)
Non-traditional treatments that are used either in place of or along with traditional medical treatments. Examples include homeopathy, chiropractic, and acupuncture.

When a doctor cuts out a tumor or other tissue from someone’s body.

Fine-needle aspiration
When a doctor removes tissue or fluid from someone’s body with a thin needle so that it can be examined under a microscope. Also called a "needle biopsy."

Material that exists inside human cells that contain “instructions” for our individual characteristics, like eye and hair color. 

Hormone therapy
Treatment that blocks or lowers the amount of hormones (substances in our bodies that control certain cells or organs) to stop or slow down the growth of cancer.

Care and support for someone who is in the final stages of a terminal illness. The goal of hospice is to relieve pain and make the person’s final months, weeks, or days more comfortable and peaceful. Hospice care can be provided wherever the patient lives; in the home, in a nursing home, in a private hospice facility, or in a hospital.

Immune system
A network of tissues and organs that work together to protect the body.

A type of treatment that helps the body fight cancer by boosting its natural defenses.

A method of putting medicine or fluids directly into a person’s blood over a period of time. An infusion uses an IV, which is a needle with a small plastic tubing that’s attached to a bag that holds the medicine.

Invasive cancer 
Cancer that started in one area of the body and is growing into surrounding, healthy tissue.

Localized cancer
Cancer that has not spread to other parts of the body.

Lymph nodes
Bean-shaped small organs that filter harmful substances from our blood.


The spread of cancer cells to another part of the body.

A doctor who treats cancer. 

Palliative care
Special medical care for people living with a serious illness. Patients do not have to have a terminal illness to benefit from palliative care. Palliative care focuses on helping patients understand their illness and feel more comfortable by treating symptoms like pain, nausea, loss of appetite, or exhaustion. 

A doctor who diagnoses diseases by studying cells under a microscope.

A prediction made by a doctor about a patient’s chances for recovery.

A fake body part that is used to replace an arm, leg, or other part that someone has lost because of disease or an accident.

A detailed medical plan followed by doctors, nurses, and other medical staff to treat a patient.

Radiation therapy
Treatment that uses high-energy rays or radioactive materials to destroy cancer cells. Radiation may cause someone to get tired.

Reconstructive surgery
Surgery to repair skin and muscles that have been damaged by cancer treatments.

When cancer comes back.

When the signs of cancer are gone. During remission, cancer may still be in the body. 

Surgery (for cancer)
An operation that removes cancer from a patient's body. 

Changes in the body caused by an illness or condition. For example, a fever is a symptom of the flu.

Systemic disease
An illness that affects a person’s entire body, not just one body part.

A group of cells in the body that aren’t normal. Cancer cells often group together to form tumors.

White blood cells
Cells that help the body fight infection.

More Information and Resources

Learn how Support Services at UT Southwestern can help you explain your illness to your children.

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