Radiation Oncology


The following glossary of terms will help you to understand the terminology that will be used during your course of treatment.  Any time you have any questions regarding your treatment, please ask the physician, nurse or the therapist who is working with you.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Adenocarcinoma: Cancer that starts in the glandular tissue, such as in the ducts or lobules of the breast.

Adenoma: A benign, non-cancerous growth starting in the glandular tissue.

Adjuvant therapy: Treatment used in addition to the main treatment. It usually refers to hormonal therapy, chemotherapy, radiation therapy, or immunotherapy added after surgery to increase the chances of curing the disease or keeping it in check.

Alopecia: Hair loss. This often happens with chemotherapy treatment or radiation therapy to the head. In most cases, the hair grows back after treatment ends.

Asymptomatic: Not having any symptoms of a disease. Many cancers can develop and grow without producing symptoms, especially in the early stages. Screening tests such as mammograms and colonoscopies help to find these early cancers before symptoms start, when the chances for cure are usually highest.

Atypical: Not usual; abnormal. Often refers to the appearance of cancerous or pre-cancerous cells.

Axillary Dissection: Removal of the lymph nodes in the armpit. They are looked at under a microscope to see if they contain cancer.

Basal Cell Carcinoma: The most common type of skin cancer. It begins in the lowest layer of the epidermis, called the basal cell layer. It usually develops on sun exposed areas, especially the head and neck. Basal cell cancer grows slowly and is not likely to spread to distant parts of the body.

Benign: Not cancer, not malignant.

Benign Prostatic Hyperplasia: Non-cancerous enlargement of the prostate that may cause problems with urination such as trouble starting and stopping the flow.

Benign Tumor: An abnormal growth that is not cancer and does not spread to other areas of the body.

Bilateral: On both sides of the body; for example, bilateral breast cancer is cancer in both breasts.

Biopsy: The removal of a sample of tissue to see whether cancer cells are present. There are several kinds of biopsies. In some, a very thin needle is used to draw fluid and cells from a lump. In a core biopsy, a larger needle is used to remove more tissue.

Bolus: A material used to act as buildup to bring the maximum dose closer to the surface of the skin.

Bone Scan: An imaging method that gives important information about the bones, including the location of cancer that may have spread to the bones. It can be done on an outpatient basis and is painless.

Brachytherapy: Internal radiation treatment given by placing radioactive seeds directly into the tumor or close to it.

Brain Scan: An imaging method used to find anything not normal in the brain, including brain cancer and cancer that has spread to the brain from other places in the body. It can be done on an outpatient basis and is painless.

Breast Cancer: Cancer that starts in the breast. The main types of breast cancer are ductal carcinoma in situ, invasive ductal carcinoma, lobular carcinoma in situ, invasive lobular carcinoma, and medullary carcinoma.

Calcifications: Tiny calcium deposits within the breast, alone or in clusters, often found by mammography. These are also called microcalcifications. They are a sign of changes within the breast that may need to be followed by more mammograms, or by a biopsy.

Cancer: All cancers cause cells in the body to change and grow out of control. Most types of cancers form a lump or mass called a tumor. The tumor can invade and destroy healthy tissue. Cells from the tumor can break off and go to other parts of the body where they can continue to grow. This spreading process is called metastasis.

Cancer Cell: A cell that divides and reproduces abnormally and can spread throughout the body, crowding out normal cells and tissue.

Carcinoma: A malignant tumor that begins in the lining layer of organs. At least 80% of all cancers are carcinomas.

Carcinoma in situ: An early stage of cancer in which the tumor is confined to the organ where it first developed. The disease has not invaded other parts of the organ or spread to distant parts of the body. Most in situ carcinomas are highly curable. cGy: Short for centigray, a unit of radiation.

Chemotherapy: Treatment with drugs to destroy cancer cells. Chemotherapy is often used, either alone or with surgery or radiation therapy.

Clinical Trials: Research studies to test  new drugs or other treatments to compare current, standard treatments with others that might be better.

Combined Modality Therapy: Two or more types of treatment used alternately or together to get the best results. For example, surgery for cancer is often followed by chemotherapy or radiation to destroy any cancer cells that may have spread from the original site.

Computed Tomography: An imaging test in which many X-rays are taken from different angles of a part of the body. These images are combined by a computer to make cross-sectional pictures of internal organs. This is a painless procedure. It is often referred to as a "CT" or "CAT "scan.

Concurrent Treatment: Treatment or therapy that is given at the same time as another treatment.

Conformal Radiation Therapy: A type of radiation treatment that used a special computer which helps shape the beams of radiation to the shape of the tumor and delivers the beams from different directions. This allows healthy tissue to be exposed to less radiation.

CT Simulator: The CT simulator is utilized to ensure the accurate mapping of the treatment area. The CT simulator creates 3D images that are used to precisely outline the tumor volumes so that your therapy team can meticulously plan a course of treatment, tailored specifically to your anatomy. Because radiation affects normal cells as well tumor cells, your treatment team carefully maps the area minimizes damage to normal tissue.

Diagnosis: Identifying a disease by its signs or symptoms, and by using imaging tests and laboratory findings. For most types of cancer, the earlier a diagnosis of cancer is made, the better the chance for long-term survival.

Differentiation: The normal process through which cells mature so they can carry out the jobs they were meant to do. Cancer cells are less differentiated than normal cells. Pathologists grade the cells to evaluate and report the degree of a cancer's differentiation.

Distant Cancer: Cancer that has spread far from its original location or primary site to distant organs or lymph nodes. Sometimes called distant metastases.

Dosimetrist: A person who plans and calculates the proper radiation dose for cancer treatment. They have knowledge of the overall characteristics and clinical relevance of radiation oncology treatment machines and equipment is cognizant of procedures commonly used in brachytherapy and has the education and expertise necessary to generate radiation dose distributions and dose calculations in collaboration with the medical physicist and radiation oncologist.

Ductal Carcinoma in situ, or DCIS: Cancer cells that start in the milk ducts but have not grown through the duct walls into the surrounding tissue. This is a highly curable form of breast cancer that is treated with surgery, or surgery plus radiation therapy.

Dysphagia: Having trouble swallowing or eating.

Dysplasia: Abnormal changes of groups of cells that may lead to cancer.

Edema: Build up of fluid in the tissues, causing swelling. Edema of the arm or leg can develop after surgery or radiation.

External Beam Radiation Therapy: Radiation that is focused from a source outside the body on the area affected by the cancer. It is much like getting a diagnostic x-ray, but for a longer time.

Fistula: An abnormal passage, opening, or connection between 2 internal organs or from an internal organ to the surface of the body.

5-Year Survival Rate: The percentage of people with a given cancer who are expected to survive 5 years or longer after diagnosis. Five-year survival rates are based on the most recent information available, but they may include information from the percentage of people with a given cancer who are expected to survive 5 years or longer after diagnosis, or from patients treated several years earlier. These numbers do not take into account advances in treatment that have often occurred. They are not helpful in predicting an individual case. They only paint a very general picture of how people in the past have done with the same type of cancer.

Gleason Grade: The most often used prostate cancer grading system. A pathologist assigns a Gleason grade ranging from 1 through 5 based on how much the cancer cells under the microscope look like normal prostate cells. Those that look a lot like normal cells are graded as 1, while those that look the least like normal cells are graded as 5.

Gleason Score: The combination of the two Gleason grades used in classifying each prostate cancer based on how the cells look under the microscope. Because prostate cancers often have areas with different grades, a grade is assigned to the two areas that make up most of the cancer. These two grades are added to give a Gleason score between 2 and 10. The higher the Gleason score, the faster the cancer is likely to grow and the more likely it is to spread beyond the prostate.

Gray: The newer, international unit of measurement of radiation transfer. One gray equals 100 rads.

Hormone Therapy: Treatment with hormones, using drugs that interfere with hormone production or hormone action, or the surgical removal of hormone-producing glands. Hormone therapy may kill cancer cells or slow their growth.

Hospice: A special kind of care for people in the final phase of illness, as well as their families and caregivers. The care usually takes place in the patient's home or in a home-like facility.

In Situ: In place; localized and confined to one area. A very early stage of cancer.

Informed Consent: A legal document that explains a course of treatment, the risks, benefits, and possible alternatives; also the process by which patients agree to treatment.

Internal Radiation: Treatment in which a radioactive substance is implanted in the body.

Interstitial Radiation Therapy: A type of treatment in which a radioactive implant is placed directly into the tissue ( not in a body cavity )

Invasive Cancer: Cancer that has spread beyond the layer of cells where it first developed and has grown into nearby tissues.

Invasive Ductal Carcinoma: A cancer that starts in the milk ducts of the breast and then breaks through the duct wall, where it invades the fatty tissue of the breast. When it reaches this point, it can metastasize elsewhere in the breast, as well as to other parts of the body through the bloodstream and lymphatic system. Invasive ductal carcinoma is the most common type of breast cancer.

Invasive Lobular Carcinoma: A cancer that starts in the milk producing glands of the breast and then breaks through the lobule walls and grows into the nearby fatty tissue. From there, it may spread elsewhere in the breast. About 15% of invasive  breast cancers are invasive lobular carcinomas. It is often hard to detect by physical examination or even by mammography. Also called infiltrating lobular carcinoma.

Linear Accelerator: A machine used in radiation therapy to treat cancer. It gives off gamma rays and electron beams. This is called external beam radiation therapy.

Localized Cancer: A cancer that is confined to the organ where it started; that is, it has not spread to distant parts of the body.

Lumpectomy: Surgery to remove the breast tumor and a small amount of surrounding tissue.

Lymph Node Biopsy: A test in which all or part of a lymph node is removed and looked at under a microscope to find out if cancer has reached the lymph nodes.

Lymph Nodes: Small bean shaped collections of immune system tissue. They remove cell waste, germs, and other harmful substances from lymph. They help fight infections and also have a role in fighting cancer, although cancers sometimes spread through them.

Magnetic Resonance Imaging (MRI): A method of taking pictures of the inside of the body. Instead of using x-rays, MRI uses a powerful magnet to send radio waves through the body. The images appear on a computer screen as well as on film. Like x-rays, the procedure is painless, but some people feel confined inside the MRI machine.

Malignant Tumor: A mass of cancer cells that may invade surrounding tissues or metastasize to distant areas of the body.

Mammogram: An X-ray of the breast; a method of finding breast cancer that can't be felt. Mammograms are done with a special type of x-ray machine used only for this purpose. A mammogram can show a developing breast tumor before it is large enough to be felt by a highly skilled health care professional. Screening mammography is used to help find breast cancer early in women who don't have any symptoms. Diagnostic mammography helps the doctor learn more about breast masses or the cause of other breast symptoms.

Margin: The edge of a tissue sample removed during surgery. A negative surgical margin means that no cancer cells were found on the outer edge of the removed tissue, and is a sign that no cancer was left behind. A positive surgical margin indicates that cancer cells are found at the outer edge of the removes sample and is usually a sign that some cancer remains in the body.

Mass: Any sort of lump, which may, or may not be cancer.

Medical Oncologist: A doctor who is specially trained to diagnose and treat cancer with chemotherapy and other drugs.

Medical Physicists: Assures the safe and effective delivery of radiation to achieve a therapeutic result as prescribed in patient care. They are responsible for equipment and source quality assurance as well as radiation safety to ensure compliance with state and federal regulations. They also oversee dose verification of the design and optimization of treatment plans. Medical Physicists have achieved post-graduate degrees in the application of physics to medicine and are certified through the American Board of Radiology.

Melanoma: A cancerous tumor that begins with the cells that produce the skin coloring. Melanoma is almost always curable in its early stages. However, it is likely to spread, and once it has spread to other parts of the body the chances for cure are much less.

Metastasis: Cancer cells that have spread to one or more sites elsewhere in the body, often by way of the lymph system or bloodstream. Regional  or local metastasis is cancer that has spread to the lymph nodes, tissues, or organs close to the primary site. Distant metastasis is cancer that has spread to organs or tissues that are farther away.

Metastatic: A way to describe cancer that has spread from the primary site to other structures or organs, nearby or distant.

Oncologist: A doctor with special training in the diagnosis and treatment of cancer.

Oncology: The branch of medicine concerned with the diagnosis and treatment of cancer.

Oncology Nurse: A nurse who specializes in the care of cancer patients.

Palliative Treatment: Treatment that relieves symptoms, such as pain, but is not expected to cure the disease. Its main purpose is to improve the patient's quality of life.

Physician Assistant (PA): A healthcare professional licensed to practice medicine with the supervision of a licensed physician. A physician assistant provides a broad range of health care services that are traditionally performed by a physician. Physician assistants conduct physical exams, diagnose and treat illness, order and interpret tests, counsel on preventive health care, and write prescriptions. They are graduates from accredited PA programs and maintain state licensure.

Port Films: Images used to verify the accurate location of the treatment area. Films or digital images are used as part of your treatment prescription.

Positron Emission Tomography (PET): A PET scan creates an image of the body after the injection of a very low dose of a radioactive form of a substance such as glucose. The scan computes the rate at which the tumor is using the sugar. In general, high-grade tumors use more sugar than normal and low-grade tumors use less. PET scans may also be used to see how well a tumor is responding to treatment.

Pre-Cancerous: Changes in cells that may, but do not always, become cancer.

Primary Site: The place where cancer begins. Primary cancer is usually named after the organ in which it starts.

Prostate-Specific Antigen (PSA): A protein made by the prostate gland. Levels of PSA in the blood often go up in men with Prostate cancer as well as other conditions. The PSA test is used to help screen for prostate cancer. It is also used to check the results of treatment.

Radiation Dose: The amount of radiation an object (such as human tissue) receives. The international units of Gray or Centigray are generally used.

Radiation Oncologist: A physician who specializes in the treatment of cancer patients using radiation therapy. Radiation oncologists work closely with other physicians such as surgeons and medical oncologists as part of a multi-disciplinary cancer team. They have comprehensive knowledge in the delivery of radiation, the benefits, and the effects.

Radiation Oncology Nurses: Are specially trained nurses that work closely with Radiation Oncologists. They are integrally involved in performing patient assessments and teaching patients and families about the treatment. Nurses also provide the best advice and emotional support needed to the patient and family members. All our nurses are licensed by the Nursing Association Board and the majority are Oncology Certified Nurses (OCN).

Radiation Therapist: A person who specializes in the administration of prescribed radiation treatments. They up and deliver your daily radiation prescription. They are graduates of certified programs of radiation therapy technology and are certified by the American Registry of Radiologic Technologists. Radiation therapists assist with the initial planning and perform simulation and treatment functions under the direction of the radiation oncologist.

Radiation Therapy: Treatment with high energy X-rays to kill cancer cells and shrink tumors. The radiation may come from external radiation (outside the body), or from radioactive materials placed directly in the tumor (brachytherapy or internal radiation). Radiation therapy may be used to shrink the cancer before surgery, to destroy any remaining cancer cells after surgery, or as the main treatment. It may also be used as palliative treatment for advanced cancer.

Recurrence: The return of cancer after treatment. Local recurrence means that the cancer has come back at the same place as the original cancer. Regional recurrence means that the cancer has come back after treatment in the lymph nodes near the primary site. Distant recurrence is when cancer spreads (metastasizes) after treatment to distant organs or tissues.

Simulation: A process involving special X-rays or CAT scans that are used to plan radiation treatment so that the area to be treated is precisely located and marked for treatment.

Staging: The process of finding out whether cancer has spread and if so, how far. There is more than 1 system for staging different cancers. The TNM staging system, which is used the most, gives 3 key pieces of information: T refers to the size of the tumor; N describes the cancer spread to nearby lymph nodes; and M shows whether the cancer has metastasized to other organs. Letters or numbers after the  T,N,M give more details about each of these factors. The TNM descriptions can be grouped together into a simpler set of stages, labeled with roman numerals I to IV. In general the lower the number, the less the cancer has spread. A higher number means a more serious cancer.

Stereotactic Radiosurgery: This new treatment method focuses high doses of radiation at a tumor while limiting the exposure that normal tissue receives. The treatment may be used for tumors that are in places where regular surgery would harm essential tissue, for example, in the brain or spinal cord.

Tumor: An abnormal lump or mass of tissue. Tumors can be benign (non-cancerous) or malignant (cancerous).

Ultrasound: An examination using a special machine that uses sound waves to visualize structures.

X-Rays: One form of radiation that can be used at low levels to produce an image of the body on film or at high levels to destroy cancer cells.