Descriptions of Biological & Medical Terms

This glossary of medical terms is specifically geared for patients with asbestos-related diseases and their families. Select from the letters or scroll below:



adjuvant therapy: Treatment used in addition to the main medical treatment. It usually refers to chemotherapy or radiation added after surgery. advanced cancer: A general term describing stages of cancer in which the disease has spread from the primary site to other parts of the body. AJCC Staging System: American Joint Committee on Cancer staging system (also called the TNM system), which describes the extent of a cancer’s spread in Roman numerals from 0 through IV. alveoli: Air cells of the lungs. asbestosis A disease involving scarring of the lung tissue. It is caused by the inhalation of asbestos fibers. ascites: Accumulation of fluid in the abdominal cavity. aspiration: To draw out by suction. In fine needle aspiration, a thin needle is used to draw up (aspirate) tissue samples for microscopic examination.


biopsy: The removal of a sample of tissue to see whether cancer cells are present. bronchi: The two main air passages leading from the windpipe (trachea). They allow air to move in and out of the lungs. bronchiole: One of the smaller subdivisions of the bronchi.


carcinogen: Any substance that causes cancer or helps cancer grow. chemotherapy: Treatment with drugs to destroy cancer cells. Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread or when it has recurred. curative treatment: Treatment aimed at producing a cure. Compare with palliative treatment. complementary therapy: Therapies used in addition to standard therapy. Some complementary therapies may help relieve certain symptoms of cancer, relieve side effects of standard cancer therapy, or improve a patient’s sense of well–being. computed tomography (CT scan): Special radiographic technique that uses a computer to combine multiple x–ray images into a two dimensional cross–sectional image. cryosurgery Treatment performed with an instrument that freezes and destroys abnormal tissues. CT scan: See computed tomography. cytokines: Proteins which occur naturally in the body, and which are similar to hormones. Intercellular mediators, cytokines differ from hormones in that they are produced by a number of tissues or cell types. They may stimulate immunity.


fibrosis: Formation of scar–like (fibrous) tissue.


gene: A segment of DNA that contains information on hereditary characteristics such as hair color, eye color, and height, as well as susceptibility to certain diseases. gene therapy: A new type of treatment in which defective genes are replaced with normal ones. The new genes are delivered into the cells by viruses or proteins.


imaging: Method used to produce a picture of internal body structures. Some imaging methods used to detect cancer are x–rays, CT scans, and magnetic resonance imaging (MRI). immunotherapy: Treatment of diseases such as cancer by stimulating the body’s own immune system. interferon: A type of cytokine protein produced by cells. Interferon helps regulate the body’s immune system. interleukin: A group of polypeptides that are members of the family of cytokines which affect functions of specific cell types and are found in small quantities. They are secreted regulatory proteins produced by lymphocytes and other cell types.


latency period: Time from exposure to a substance to the onset of a disease. Example: time from asbestos exposure to development of mesothelioma. lobectomy A surgical procedure in which the lobe of a lung is removed.


macrophages: A type of white blood cell that engulfs and destroys foreign materials. magnetic resonance imaging (MRI): A scan that uses magnetic fields, radio waves, and a computer to create images of selected areas of the body. mesothelioma: Malignant tumor of the mesothelium, usually of the lung, generally caused by exposure to asbestos fibers. mesothelium: Tissue formed by specialized cells lining the chest, abdominal cavities, and the outer surface of most internal organs. Mesothelium helps protect the organs by producing a lubricating fluid that allows the organs to move. MRI: See magnetic resonance imaging


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.


palliative treatment: Therapy that relieves symptoms, such as pain or blockage, but is not expected to cure the cancer. Its main purpose is to improve the patient’s quality of life. PDT: See photodynamic therapy. peritoneal mesothelioma: Cancer of the lining of the abdomen. PET scan: See positron emission tomography photodynamic therapy (PDT): Cancer treatment that uses the interaction between laser light and a substance that makes cells more sensitive to light. When light is applied to cells that have been treated with this substance, a chemical reaction occurs and destroys cancer cells. pleura: The membrane lining the lungs and chest cavity. pleural effusion: Accumulation of fluid in the lungs. pleural mesothelioma Cancer of the pleura, or the membrane that lines the lungs and chest cavity. 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 (sugar). The scan computes the rate at which the tumor is using the sugar. In general, high–grade tumors use more sugar and low–grade tumors use less. pneumonectomy An operation to remove an entire lung. pulmonary function test: Breathing tests used to measure lung capacity and lung and chest wall mechanics.


radiation therapy (radiotherapy): Treatment with high–energy rays such as x–rays to kill or shrink cancer cells. radiotherapy: See radiation therapy. risk factor: Anything that increases a person’s chance of getting a disease such as cancer. Different cancers have different risk factors.


small cell lung cancer: A type of lung cancer in which the cells are small and round. staging: The process of finding out whether cancer has spread and if so, how far. SV40: A virus found in monkeys. It may be linked to human mesothelioma and other cancers. The virus was a contaminant of polio vaccines in the United States in the 1950s and early 1960s. synergistic: Acting together. A synergistic agent can act with other agents to produce an effect greater than that of the sum of each one acting alone.


T–cells: White blood cells made in the thymus gland. They play a large role in the immune response against transplanted organs and tissues, and cancer cells. thoracoscopy: A surgical technique for tissue sampling in which a telescopic instrument (thoracoscope) fitted with a lighting system is inserted through a puncture in the chest wall. The physician can see the tumor and sample it using a forceps–like tool.