Basic Cancer Terms You Need to Know

Medically Reviewed by Jennifer Robinson, MD on February 21, 2024
4 min read

When you hear doctors talk about cancer and its treatment, it can sound like they are speaking a foreign language. It helps to learn some of the most common terms they use and what those words mean. Understanding the lingo can help you work with your doc as you fight your disease together.

Ablation (.a-BLAY-shun) is a minimally-invasive cancer treatment that uses heat, cold, or alcohol to directly destroy tumors

Acute (a-CUTE) describes symptoms that get worse very quickly but don’t last very long. Sometimes, symptoms that start as acute can stick around and last for a while. Then they become chronic (see below).

Atypical (ay-TIP-ih-cul) is a medical word for “abnormal.” Doctors may use this word to describe cells or body tissues that look unusual under a microscope. They might also say your case is atypical if you don’t have the usual symptoms of your type of cancer.

Benign (buh-NINE) means that a tumor is not cancer. It doesn't spread to other parts of your body.

Biopsy (BYE-opp-see) is when a doctor removes a small piece of tissue from your body and sends it to a lab for testing. It’s the main way to diagnose cancer. Your doctor may use a needle, scalpel, or other tool to do the biopsy.

Carcinoma (CAR-sin-OH-muh) is cancer that starts in the lining of your organs or the outer layer of your skin.

Chemotherapy (KEE-moh-THER-uh-pee) is a treatment that uses powerful drugs to kill cancer cells or to stop them from growing.

Chronic (CRAH-nik) describes a condition that lasts a long time.

Immunosuppressive (ih-MYOON-oh-suh-PRESS-iv) refers to treatments that turn down your body’s immune system so it can’t fight infections as well. People who are about to get a bone marrow or organ transplant get these therapies to keep their bodies from rejecting the new tissue.

Immunotherapy (ih-MYOON-oh-THER-uh-pee) is treatment that stimulates the immune system to help the body fight diseases like cancer.

In situ (in SIGH-too) describes when abnormal cells look like cancer cells that have not spread to other tissue nearby.

Malignant (muh-LIG-nant) refers to cancer cells that can invade and kill nearby tissue and spread to other parts of your body.

Mass is a medical word for a solid group of abnormal cells.

Metastasis (meh-TASS-tuh-sis) is the spread of cancer from the place where it started. If it has spread far, doctors will call it “distant metastasis.” The word for more than one metastasis is “metastases” (meh-TASS-tuh-sees). If the cancer has spread, your doctor may say it has “metastasized.”

Oncology (on-COLL-uh-gee) is the type of medicine that focuses on cancer. Doctors who specialize in oncology are called oncologists. Other health professionals like nurses and pharmacists can specialize in oncology, too.

Primary cancer is the original cancer in your body. If the disease spreads or comes back, this is called metastasis.

Prognosis (prog-NO-sis) is a medical word for “outlook.” It includes your chances of recovering from the cancer, the chances the disease will come back, and your doctor’s predictions for the course of the disease. Even if you have the same type of cancer as someone else, your prognosis will be unique to you.

Radiotherapy (RAY-dee-oh-THER-uh-pee) is treatment that uses radiation to kill cancer cells and shrink tumors. It is also called “radiation therapy.” You might get it from outside the body through special machines, or inside the body, such as with your doctor might put a tiny radioactive implants placed inside the part of your body where the cancer is (brachytherapy).

Recurrence (ree-CUR-ents) means the cancer has come back after treatment. It can happen at the place where the cancer started (“local”), near where it started (“regional”), or farther away in your body (“distant”).

Refractory (ree-FRACK-tor-ee) describes a condition that does not get better with treatment. Your doctor may also say your cancer is resistant.

Remission (reh-MIH-shun) means your signs and symptoms of cancer have gone away. If you have no more signs or symptoms at all, it’s a complete remission. If you still have some but not as many as before, it’s a partial remission. Remission doesn’t necessarily mean your cancer has been cured. It means the disease is under control.

Secondary cancer is a new primary cancer that appears after you’ve already been treated for cancer. This cancer is different from the one you already had.

Stage is a term doctors use to describe how far along your cancer is. The stages are 0 through IV, and the higher the number, the more advanced the disease is. The stage is based on how big the tumor is, how far it has grown into neighboring tissues, whether your lymph nodes have cancer, and whether the disease has spread to other parts of your body.

Targeted therapy is treatment that specifically identifies and targets cancer cells.

Tumor (TOO-mer) is an abnormal lump of body tissue. You can get a tumor if cells grow and copy themselves too fast or don’t die when they should. A tumor can be malignant (cancerous) or benign (not cancerous).

Your doctor may use other words that are specific to your kind of cancer, too. But remember: If you hear something you don’t understand, don’t be afraid to speak up and ask the doctor to explain it in simple terms.