For Parents: Medical Terms Made Easy

Contact Family Connections


When a parent is diagnosed with cancer, doctors, relatives, and friends frequently start using a new set of words such as "lymph nodes," "biopsy" and "infusion." This can be confusing, especially to children.

Here are some of the terms that you and your team of supporters will probably need at some point. You might find it helpful to share these definitions with your family as your circumstances require, simplifying them when necessary so that younger kids can understand.

As new terms come up, and you are not sure how to explain a word, test, or procedure to your children, ask your doctor, nurse, or other member of the health care team. They may be able to give you some simpler language that will help. The patient resource room or library where you receive care is another place to turn to as well.


An illness or condition that develops quickly or in a short space of time. The opposite of acute is "chronic".


Alternative Therapy

Approaches to treating cancer that are considered outside the standard of cancer care by most health care professionals.




Proteins produced by a person's immune system to fight an infection.



A growth that is not cancer.



A tiny piece of tissue is removed from a person's body and studied through a microscope to see if a person has cancer and, if so, to determine what kind. A biopsy helps a doctor make a diagnosis and choose the right treatment. A medicine called anesthesia helps patients stay comfortable so they feel no pain while the biopsy is done.


Bone Marrow

Bone marrow consists of cells inside some of our bones that produce all types of blood cells. These include red blood cells that carry oxygen, white blood cells that fight infections, and platelets that help blood to clot.




A group of more than 100 diseases in which cells that are not normal divide rapidly. These quickly growing abnormal cells usually develop into a tumor. Cancer can spread to other parts of the body, but not to other people the way colds do.



Cancer in Situ

Cancer that is just starting and has not affected any nearby tissue.




Drugs that are used to destroy cancer cells. When you have chemotherapy, you may temporarily lose your hair, feel very tired or nauseous, develop mouth sores, and be at risk for infections. The kinds of side effects you have depend on the drugs you are taking. All chemotherapy drugs do not cause the same side effects, and the same drug affects different people differently.



An illness or condition that lasts over months or years. It is the opposite of "acute."


Clinical Trials

Research studies that test new treatments in people with cancer. The goal is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new methods of surgery or radiation therapy, or may compare a new treatment with current standard medical practice.


Complementary Therapy

Some people want to use treatments along with standard medical approaches, often to reduce side effects or treatment-related anxiety or stress, and improve overall well being. These methods include acupuncture, meditation, and yoga.


Complete Blood Count (CBC)

A blood test that counts the number of red blood cells, white blood cells, and platelets in someone's blood. Red blood cells are shaped like donuts and carry oxygen from the lungs to the rest of the body. There are about five million red blood cells in one cubic millimeter of blood (that is a lot of blood cells in a very tiny space). White blood cells are bigger than red blood cells and help the body fight off infections. One cubic millimeter of blood has about 10,000 white blood cells. Platelets are the smallest blood cells and help stop bleeding. Normally, there are between 100,000 and 300,000 platelets in one cubic millimeter of blood.

Drug Resistance


Cancer cells can become "used" to the drugs the doctor prescribes to fight your disease. When this happens, the drugs no longer work to combat your cancer, and others must be tried instead.




When a physician cuts something, such as a tumor or organ, out of your body.



Fine-Needle Aspiration

For this test, also called a "needle biopsy," a doctor or assistant puts a small needle into your body and takes out a little tissue or fluid. Someone then looks at this under a microscope to see if there are any cancer cells in it.



Children often look or act like their parents. This is because parents pass down material contained in a man's sperm and a woman's eggs called genes. Genes are made up of DNA (which carries the genetic information in each cell). Genes affect children's looks, personality, and behavior. Genes are also important in normal body growth.



Genetic Testing

Sometimes genes change, or mutate, from their normal state, and such changes can lead to cancer growth. If certain mutated genes are passed on to children through the father's sperm or the mother's eggs, these children may also have an increased chance of developing cancer at some future point. In some families where more than one person has cancer, or when particular types of cancer occur, especially at unusually young ages, family members may have their genes tested for such changes. This is called "genetic testing", a process that involves a blood sample, education, and genetic counseling.




We all have substances in our livers, kidneys, and other organs of our bodies that control how fast we grow, how our bodies work, and how we reproduce. These are called hormones.




When it is likely that someone will die from cancer or some other illness in the near future, he or she can obtain care and support from a hospice program. This care and support will not cure the cancer, but will make these final months, weeks, or days more comfortable and peaceful. A patient can have hospice care either in the home or in a specialized hospital or wing of a hospital.



Immune System

When you get sick, your body has a defense system that attacks the infection. This is called your immune system. Certain cancer medications can weaken your immune system. Certain medications can help strengthen your immune system.



An infusion is like a shot, except that it puts medicine or fluids directly into your blood over a longer period of time.





An IV or intravenous is a tiny catheter (straw-like tube) that is put into a vein through your skin, typically on the arm. The IV is attached to a bag that holds your medicine, which flows from this bag into the vein, and then into your blood. At that point, the medicine can travel through the body and attack cancer cells.



Lymphatic System

The collection of tissues, lymph nodes, and other organs that drain the tissue fluid called lymph into the bloodstream.



Lymph Nodes

Bean-shaped small organs also called lymph glands in our bodies. These organs filter waste from cells and bacteria from our blood. They are part of our immune system.




Another word for "cancer."




This happens when a part of the cancer breaks off from where it started and travels to a new place in the body. The cancer will begin to grow in the new place.




The lowest point in white blood cell, red blood cell, and platelet counts following treatment.



A low white blood cell count of neutrophils, which are cells very important in the body's fight against infection.



Doctors who specialize in treating cancer. Depending on the type of treatment they provide, these specialists can be medical oncologists, surgical oncologists, or radiation oncologists.

Palliative Treatment


This type of treatment does not cure cancer, but helps the patient to feel more comfortable. It does this by controlling pain or other physical problems caused by the cancer, and by providing emotional and spiritual support. Hospice services generally provide palliative treatments, although these treatments are also widely available in hospitals, clinics, and other care centers.




To find out if a patient has cancer, someone looks at the patient's tissue or fluids under a microscope to search for abnormal cancer cells. Pathologists can also see how these cancer cells have changed over time.



These disc-shaped blood cells help in blood clotting.



Primary Tumor

The place in the body where the cancer begins.




A prediction made at the time of the initial diagnosis that describes what will probably happen to a patient in the future. This prediction is based on the type of cancer, where it is located in the body, and whether it has spread into other areas.




A medicine that is given to a patient to prevent side effects rather than to treat the disease. For example, anti-nausea medicine may be given before chemotherapy to prevent or reduce a patient's feeling nauseated.

However, "prophylactic" is not just used in reference to side effects. A prophylactic procedure may be performed to prevent the development of a primary cancer. For example, some women at increased risk for breast cancer may decide to have a prophylactic mastectomy (surgery to remove a breast).



A detailed medical plan that doctors, nurses, and other medical staff follow when treating cancer patients.



Radiation Therapy

Treatment of cancer with high-energy rays (similar to X-rays) that destroy cancer cells. The side effects of radiation therapy depend on what part of your body is being treated. For example, your skin might get red in the location where you receive radiation. If your head is being treated, you might lose your hair. If your stomach is being treated, you might get nauseated. And if your head and neck are being treated, you might have a hard time swallowing and eating.

Most people complain of being tired after receiving radiation treatments over time. Children sometimes mistakenly think that radiation can make someone radioactive, but that's not true.




The disappearance of symptoms and cancer cells as a result of treatment. A person is said to be in remission when all signs of the cancer are gone from the body. Remission is not the same as a cure. A remission can last a short time or a long time.



Side Effects

Unpleasant symptoms that sometimes occur when a patient is treated for cancer. Two people with the same type of cancer or the same treatments will not necessarily have the same side effects.



Stem Cells

Cells from which all blood cells develop. We all have three types of blood cells: red (to carry oxygen), white (to fight infection), and platelets (to help blood to clot).



Surgery (for Cancer)

An operation performed to remove cancerous tumors from a patient's body. During surgery, a doctor tries to remove as many cancer cells as possible. Some healthy cells may also be removed to make sure that the cancer is gone.




What you feel as a result of an illness. When you are sick, you usually have symptoms, like a fever, which tell you that something is not quite right.



Systemic Disease

This is an illness that you have throughout your body, not just in one location like the lung or liver.




An abnormal clump of tissue. Cancer cells usually group together to form tumors.


White Blood Cells

Cells that help the body fight infection.

Adapted from: Heiney SP, Hermann JF, Bruss KV, Fincannon JL. Cancer in the family: Helping children cope with a parent's illness. Atlanta: American Cancer Society, 2001: 38. Reprinted with permission. Also adapted from "Commonly used cancer terms: A guide for people living with cancer," published in 2002 by Pharmacia Corporation (now owned by Pfizer Corporation).