Cancer comes with its own set of language—full of complex cancer terms, acronyms, and medical phrases that can feel confusing and overwhelming. Whether you’re a patient, caregiver, or loved one, trying to understand these cancer terms can add extra stress during an already challenging time.
To help make things a little clearer, we’ve created this glossary of common cancer terms. It’s designed to break down the medical jargon and provide straightforward definitions so you can feel more confident and informed during appointments, discussions, and decision-making.
Whether you’re just beginning to learn about a diagnosis or supporting someone through treatment, we hope this resource helps make the path ahead a little easier to navigate.
Tip: This might be a good article to print out and bring with you to doctors’ appointments, especially in the beginning of your cancer journey.
Disclaimer: We are not medical professionals and this information is not meant to replace information given to you by your doctor. It was, however, sourced from credible organizations such as the NIH, American Cancer Society and the Mayo Clinic.
Adjuvant Therapy
This refers to any sort of treatment given after your first treatment to reduce the risk of the cancer coming back. cancer
Benign
A tumor or growth that is non-cancerous and not likely to spread to other parts of the body. While benign tumors can grow, they don’t invade surrounding tissues or metastasize like malignant (cancerous) tumors.
Biopsy
A surgical procedure used to figure out whether a tumor is benign or cancerous. In this test, a small piece of tissue is removed from the tumor and examined under a microscope to check for the presence of cancer cells. The tissue is examined by a pathologist (someone who is expert in identifying the changes in body tissue caused by disease). This microscopic study of tissue confirms or rules out a diagnosis of cancer.
Blood cells
Cancer patients undergo routine blood tests to monitor their blood cell counts during cancer treatment. Usually they will be monitoring platelets, red blood cells, and white blood cells.
- Platelets are the type of blood cell that help stop bleeding. When these are low you may bruise easily or bleed more easily. Low platelet counts may sometimes be called thrombocytopenia. Patients may receive a platelet transfusion when their counts become critically low.
- Red blood cells (RBCs) are the blood cells that contain hemoglobin, the substance that carries oxygen to all of the cells of the body. Anemia is when patients have low red blood cells, which can cause them to feel fatigued or short of breath. When anemia is more severe patients may have to pause treatment or adjust dosages.
- White blood cells (WBCs) are the blood cells that help the body fight infection. There are five types of white blood cells. During treatment, doctors closely monitor the levels of neutrophils, which help fight bacterial infection. A low white blood cell count is sometimes called neutropenia. Medications may sometimes be given to help stimulate bone marrow production to help increase white blood cell counts.
Bone Scans
Bone scans can show abnormalities long before they show up in X-Rays, which is why the doctor may order one.
The radioactive fluid is given through an IV and is absorbed by your bones as it travels through your body. You have to drink a lot of water or juice right after the fluid is injected to clear your body of radioactive material not absorbed by your bones.
The bone scan may take about an hour and again, you have to lie very still while the camera moves back and forth. You might be asked to change positions several times to get different images. Because no X-Rays are emitted, you can have someone stay in the treatment room with you.
The radioactive material or tracer concentrates in areas where there is a lot of activity, like normal growing bone or in bone tumors or bone infections. These areas will show up as “hot spots” on the scan.
CT (Computerized Tomography) Scan
CT Scans (also known as CAT Scans) combine X-Rays and computers to produce very detailed cross sectional images of your body.
Depending on what part of your body is to be scanned, you may be given ‘contrast’ solution to make things show up better on the scan. The good thing about CTs is that they are quick, but you need to lie very still to get a good scan.
After the scan is done, it can be computer reconstructed to show 3D images of the part of your body that was scanned. Because the machine produces X-Rays, the technician is in a separate room near the computer, but can talk with you through an intercom.
You will probably be alone in the room, unless you request that someone be with you. That person will need to wear a lead vest to protect them from the X-Rays.
Chemotherapy
A form of treatment that uses drugs to kill cancerous and other fast-growing cells in the body. Chemotherapy is often given through an IV but can also be administered through injection or taken orally in pill form.
External Central Lines
The most common is the Hickman Line (named after the person who developed them). From the tip in your vena cava (a large vein carrying deoxygenated blood into the heart), the other end of the catheter is “tunneled” under your skin for a short distance, where it exits through another small incision at a spot near your breastbone.
The catheter branches out into a couple of smaller tubes called lumens, which hang on the outside of your body. A sterile dressing covers the exit site at all times.
The advantage of this type of line is the number of lumens; you can have several different types of fluids or meds being infused at the same time through different lumens. Sometimes, if the drugs are compatible, you might have two different drugs going through the same lumen at the same time.
- A Peripherally Inserted Central Catheter (PICC) works along the same principle, with the tip ending in your superior vena cava, but the insertion point and exit of the catheter lumens is in your arm not your chest. These can have one or two lumens. Often, they’re used when treatment is short term or until a more durable central line can be surgically implanted. PICC lines are simpler and less invasive than other central catheters and can be inserted by a nurse.
Immunotherapy
A type of treatment that utilizes the body’s own immune system to fight cancer cells. It works by either boosting the immune system’s ability to recognize and attack cancer cells, or by modifying immune cells to specifically target cancer.
MRI (Magnetic Resonance Imaging) Scan
Most MRI scans take between 30 and 90 minutes. Your only job is to remain completely still because even slight movement can spoil the images.
During the scan you will hear a variety of sounds such as humming and hammering. It may sound like the technician is hitting the side of the scanner with a large hammer. These sounds are normal. You may be given earplugs or stereo headphones to muffle the noise and in most MRI centers you can bring in an iPod, but don’t be surprised if the music is drowned out by the noise.
You may be given ‘contrast’ solution during your MRI. This is a liquid that you either drink or is injected into one of your veins through an intravenous line (IV) and it helps the doctors and radiologists to see the different structures and blood vessels.
Other than maybe being a little uncomfortable (and loud!), an MRI is completely painless (except if you need an IV put in for the contrast) and you should have no side effects to worry about.
Malignant
A cancerous tumor that is actively growing, invading surrounding tissues, and potentially spreading to other parts of the body. Malignant tumors are considered dangerous and can be life-threatening if not treated.
Metastasis
A term used to describe cancer cells that have spread from where they originally formed to another part of the body. Cancers that have metastasized may do so locally or distantly. The more distant the metastasis, the more difficult to cure.
NED
Stands for no evidence of disease and is used when tests, physical exams, and scans show that all visible signs of cancer have disappeared. NED does not necessarily mean that a patient is cured because there still may be microscopic cells of cancer that are undetectable by current technologies.
Oncologist
A doctor who treats cancer patients
PET (Positron Emission Tomography)
Positron emission tomography is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption.
Cancer cells have a higher metabolic rate than normal cells. Because of this, during a PET scan, cancer cells will light up as bright spots to help with detection if the treatment is working or if there is growth in the cells.
Radiation therapy
A form of treatment that uses electromagnetic waves or particles of radiation to kill or control the growth of cancerous cells. Some radiation treatments use radioactive substances that are given orally or through an IV. Most patients feel little to no discomfort when radiation is administered into the body but it may cause skin to become temporarily irritated, swollen, or blistered.
Relapse/Recurrence
Cancer returning after a period of remission.
Remission
When cancer is no longer detectable after treatment.
Scalp cooling
An innovative treatment in which a cold cap is placed on a cancer patient’s head while they are being given chemotherapy drugs. This treatment reduces the temperature of the scalp to a very low temperature to reduce the amount of chemotherapy drugs that can reach the scalp (when those drugs are not treating a head or brain-related cancer) to lessen the likelihood of healthy hair cells being killed off from chemotherapy.
Subcutaneous (under the skin) implantable ports
This type of line is usually referred to as a medi-port or port-a-cath. Unlike a Hickman line, an implantable port is completely under the skin. This type of catheter is surgically implanted, usually in your chest, but some people also have them in their arms. It is usually done with a general anesthetic.
One end of the catheter is fed into a large vein leading directly into your heart. The other end is attached to a small chamber called a portal.
The portal is made of metal and/or plastic with a rubber top that seals it and is placed under your skin. Some devices even have two rubber areas so you can have two access lumens at a time (decreasing the chance of needing a peripheral IV in your arm).
You will feel a small bump under your skin where the port has been placed. When you need to use your port, it is accessed with a special needle (a Huber needle) that has a tube attached to it. Your meds or whatever will flow through the needle, into the catheter and then into your bloodstream. The needle and short tube will stay in for the length of your infusion or your hospitalization and then will be removed before you go home.
After a while, the skin over your port becomes tougher and less sensitive, so you won’t necessarily feel it every time it is accessed. However, especially at the start, you can use an anesthetic cream like EMLA to numb the area before it is accessed (EMLA Cream works by numbing the surface of the skin for a short time. It is put on the skin before certain medical procedures). You will need to remember to do this before you get to the clinic or hospital, so it has time to work and you don’t delay getting your bloodwork or infusion.
Staging
The process of categorizing the size of cancer and if and where it has spread from the primary site.
Stage 0 means no cancer but only abnormal cells that potentially could become cancerous are present.
Stage I or early stage cancer is when cancer is small and only in one area.
Stage II and III is when cancer is larger and has grown into nearby tissues or lymph nodes. Stage IV, also known as metastatic or advanced cancer, is when cancer has spread to other parts of the body.
Tumor Markers
Some tumors are abnormal growths of cells that make proteins, which can be measured in the blood. If these are elevated, it is one way to measure the activity of the cancer. Examples are bHcg, AFP and LDH in germ cell tumors.
Targeted Therapy
Treatment that targets specific molecules involved in cancer cell growth.
Conclusion
Please know that this is not an exhaustive list of cancer terms so if you come across a term that you’ve never heard of, email us and we’ll add it to this article!
Remember: it’s totally okay not to know understand these terms right away. Take it one step at a time, and don’t be afraid to ask your doctors, nurses, or support team to explain anything you don’t understand. You deserve to feel informed and supported every step of the way.
You’re not alone in this.
Are you a cancer survivor interested in telling your story, sharing advice or lessons learned during your cancer journey? We believe everyone’s story is unique, but there’s a powerful connection between anyone who’s faced cancer. By sharing your story, you can inspire and give hope to others who are going through similar struggles.
Please contact Kelly Wooley, Marketing and Communications Manager, if you’re interested. We would love to hear from you!
Want to stay connected? Sign up for our newsletter to learn about our latest events, resources and patient programs!
We’ve also compiled helpful resources, in addition to our blog articles, to help provide you with as much information as possible. The most important thing you can do is to educate yourself. We are here to help and show you that you’re not alone!