Absolute neutrophil count ( ANC): A measurement of the number of mature neutrophils (a type of white blood cell) that are available for fighting infection. A low ANC increases the risk for infection.

Adenocarcinoma: A subtype of non-small cell lung cancer.

Adenosquamous carcinoma: A subtype of non-small cell lung cancer.

Adhesion: Scar tissue that can form after surgery or radiotherapy.

Adjuvant therapy: Anti-cancer therapy given after another initial therapy such as surgery.

Alopecia: Hair loss during cancer treatment that is almost always temporary and grows back when therapy is finished.

Alveolus: The smallest unit of the lung that is responsible for exchanging oxygen for carbon dioxide and other gases.

Anemia: A shortage of red blood cells that can cause weakness and fatigue.

Angiogenesis: The process of developing new blood vessels.

Anti-angiogenesis therapies: Drugs that prevent development of new blood vessels that supply blood to the tumor, thereby stopping or limiting tumor growth.

Antibody: A substance made by B-lymphocytes that reacts with antigens (particularly proteins) on viruses, bacteria, and some cancer cells to mark them for removal.

Antiemetic: A drug that reduces or prevents nausea and vomiting.

Antigen: Proteins located on the surface of all cells. The immune system uses antigens to determine whether cells are a necessary part of the body or need to be destroyed.

Antisense Drugs: Drugs that are currently being developed to stop the production of cancer-causing proteins at the genetic level.

Atelectasis: A partially or totally collapsed lung.

BAC: Bronchioloalveolar carcinoma, a subtype of NSCLC.

Biologic therapy: Treatments that use or stimulate the immune system to fight infection and the cancer.

Biopsy: Surgical removal of a small piece of tissue for evaluation under a microscope.

Bone marrow: The spongy material that is found inside our bones. It contains immature cells called stem cells that develop into 3 types of cells: red blood cells that deliver oxygen and take away the waste product carbon monoxide; white blood cells that protect from infection; and platelets that help the blood to clot.

Brachytherapy: Radiation treatment that uses radioactive pellets inserted into a flexible tube placed inside the breathing passage to directly treat lung cancer.

Bronchial basal epithelial cells: Cells that line the breathing passages and a common site where cancers develop.

Bronchial carcinoma: A general name for all types of lung cancer.

Bronchial-sleeve resection: Removal of part of one bronchial tube with reattachment of the remaining ends.

Bronchioloalveolar carcinoma (BAC): A subtype of non-small cell lung cancer that can sometimes grow slowly.

Bronchorrhea: A cough producing large amounts of phlegm.

Bronchoscopy: Viewing and biopsy of the bronchial tubes with a type of endoscope called a bronchoscope.

Bronchus: Either of 2 tubes that are the main airways into the lungs that branch from the trachea and enter the lungs.

Bulky disease: Any tumor that measures greater than 10 centimeters.

Cancer: An abnormal cell that cannot be controlled by the body’s natural defenses. Cancerous cells can grow and eventually form tumors.

Carcinoma in situ: A tumor that is still confined to the innermost layer of the lung where it first arose.

Catheter (intravenous): A device that is temporarily or permanently put into a vein that makes it easier to give medications.

Cerebrospinal fluid: The fluid that is present around the spine and brain. This fluid may be examined to see if lung cancer has spread to this part of the body.

Cervical mediastinoscopy: Insertion of an endoscope through an incision near the collarbone to examine the mid-chest, especially the lymph nodes.

Cervicotomy: A surgical incision into the chest or the collarbone.

Chemotherapy: Treatment with drugs (“chemo”) to stop the growth of rapidly dividing cancer cells.

Chemotherapy cycle: The term used to describe the process in which chemotherapy is given, followed by a period of rest in which the body is allowed to recover.

Chemotherapy regimen: Combinations of anticancer drugs given at a certain dose in a specific sequence according to a strict schedule.

Chronic obstructive pulmonary disease (COPD): A name for a variety of long-term breathing problems with various causes such as aging and smoking.

Cilia: Minute hair-like parts of the lung that move continuously (when healthy) to remove mucus from the lung.

Clinical trial: A research study in which a new treatment is given to patients to determine whether it is safe, more effective, or less toxic than a current standard of care.

Complete remission: This term is used when all signs of the disease have disappeared after treatment.

Complete response (complete remission or CR): The term used when all signs of the cancer have disappeared.

Computed axial tomography scan (CT scan or CAT scan): This imaging test provides a series of detailed pictures of the inside of the body using an x-ray machine linked to a computer.

Cure: The disease is gone. There are no signs or symptoms of lung cancer, and a significant period of time has passed during which there are no relapses.

Diaphragm: The thin muscle below the lungs and heart that separates the abdomen from the chest that is integral to the push-pull mechanism of breathing.

Diffusion capacity: A measure of how well the lungs take in air to exchange oxygen for carbon dioxide and other gases.

Disease progression: The term used if the disease worsens despite treatment (also called treatment failure.)

Distal: The portion of the lung that is farthest from the mouth.

Dose intensity: A term used to describe giving the highest possible doses of drug possible over a specific period of time with acceptable side effects. This approach has been shown to be very effective in curing some cancers.

Durable remission: When a complete response lasts for years—in most cases, the longer the remission the better the long-term outcome and possibility of cure.

Dysphagia: Difficulty swallowing.

Dyspnea: Difficulty breathing.

Echocardiogram: Use of ultrasound to examine the heart.

Emphysema: The loss of elasticity in the lungs that results in an inability to exchange oxygen for carbon dioxide and other gases.

Etiology: The study of the cause of disease. In cancer, there are often multiple causes.

Extensive-stage SCLC: Small cell lung cancer that has spread to distant organs.

Field cancerization: Some lung tumors seem to arise in broad areas of lung tissue that contain damaged DNA. One theory about how lung cancer grows proposes that substances that trigger damage to DNA do so in sweeping areas, not just in single cells, as may happen with other types of cancer.

Fatigue: A decreased capacity for activity that is often accompanied by feelings of weariness, sleepiness, or irritability.

Genes: The basic building blocks of heredity which are present in all cells.

Gene therapy: Therapies that alter the genetic structure of tumor cells, making them more susceptible to either the immune system or chemotherapy drugs.

Grade: A method of classifying a tumor on the basis of how aggressively it is growing.

Hemoptysis: Coughing blood.

Hilum: Area on the lung where the bronchial tubes, blood vessels, and nerves enter.

Histology: The study of tissues to determine their specific characteristics, which may lead to identifying a specific type of lung cancer.

Hypercalcemia: An excess of calcium in the blood that can sometimes be caused by the secretion of a hormone by some type of tumors.

Hypothyroidism: A condition in which there is lower than normal production of thyroid hormone. Low thyroid levels can lead to a variety of effects, including weight gain and sleepiness.

Immune system: The body’s important defense mechanisms against infection and fighting disease.

Immunotherapy: See biologic therapy.

Improvement: This term is used if a tumor shrinks following therapy but is still more than one-half of its original size.

Intercostal space: The space between the ribs.

Interferons: Proteins that strengthen the immune system. Interferon-alfa helps fight cancer cells.

Interstitial radiotherapy: Implanting a very small seed containing radiation within a tumor to kill it.

Lambert-Eaton Myasthenic Syndrome: A cluster of symptoms such as muscle weakening that can be caused by some forms of lung cancer.

Laparoscopy: Passing a tube through the abdominal wall to obtain a small sample of tissue for examination under the microscope.

Limited-stage SCLC: Small cell lung cancer that is limited to one lung and its lymph nodes; it has not spread to distant organs.

Lobe: One major section of one lung. The right lung has 3 lobes, but the left has just 2 to make room for the heart and other organs.

Lobectomy: Removal of one lobe of either lung.

Local therapy: A therapy that only affects cancer cells in the treated area.

Lymph: The watery fluid in the lymph system that contains white blood cells (lymphocytes).

Lymph nodes: Small bean-shaped glands located along the small vessels of the lymphatic system. There are thousands of lymph nodes located throughout the body, with clusters of them in the neck, under the arms, and in the chest between the lungs, abdomen, and groin. Lymph nodes filter lymph fluid, trapping and destroying potentially harmful bacteria and viruses. Lymph nodes may be enlarged as a result of benign as well as malignant causes.

Lymphadenectomy: Removal of all lymph nodes and lymphatic vessels that drain the lung as part of lung cancer surgery.

Lymphangiogram: An x-ray of the lymph system. A contrast medium is injected into the lymph fluid to outline the nodes and vessels so they can be easily visualized on the x-ray film.

Lymphatics: Lymph channels and vessels that transport lymph fluid. They are similar to blood vessels, but smaller.

Lymphocytes: A type of white blood cell. Lymphocytes, carried along by the lymph fluid, are the part of the immune system that fight infection.

MRI (magnetic resonance imaging): An MRI uses magnets and radio frequency waves to produce images of the inside of the body. An MRI can provide important information about tissues and organs that is not available from other imaging techniques.

Malignant: Cancerous—a malignant tumor is a cancerous tumor.

Mediastinal pleura: The lining of the inner chest between the lungs.

Mesothelioma: A type of cancer that grows on the outer surface of the lung that is often mistaken for lung cancer and usually linked to inhalation of fibers like asbestos.

Metastasis: The spread of cancer to other tissues.

Mucositis: The medical term for mouth sores.

Myelosuppression: A reduction in the bone marrow’s ability to make red blood cells, white blood cells, and platelets.

NSCLC: Non-small cell lung cancer.

Nebulize: To reduce to a fine spray or to atomize.

Neoadjuvant therapy: Chemotherapy or radiotherapy used before surgery to shrink a tumor.

Neutropenia: An abnormally low level of neutrophils (the white blood cells responsible for fighting bacterial infections).

Neutrophils: The primary type of white blood cells found in the body.

Oat cell: An older, less-used name for small cell lung cancer.

Oncologist: A doctor who specializes in treating cancer. Some oncologists further specialize in chemotherapy (“medical oncologists”), radiotherapy (“radiation oncologists”), or surgery (“surgical oncologists”).

Palliation: The relief of pain and other symptoms without intent to cure the disease.

Pancoast Syndrome: A collection of symptoms that can be caused by some types of lung cancer.

Papillary: A subtype of non-small cell lung cancer.

Para-aortic: The area close to the aorta. The aorta is the large heart vessel that gives rise to the arteries.

Partial remission: The term used when a cancer has shrunk in size (usually at least in half) but has not totally disappeared. The cancer can still be detected, and other treatments may be recommended.

Pathologist: A doctor who specializes in studying disease through the gross and microscopic evaluation of body tissues and organs. Any tissue suspected of being cancerous must be examined by a pathologist to confirm the diagnosis.

Performance status: Performance status is used to describe a person’s ability to do everyday activities such as eating, walking, bathing, etc. There are also scales that can be used to specifically quantify status.

Perfusion scan: A test that measures how well the lungs take in air to exchange oxygen for carbon dioxide and other gases.

Peripheral neuropathy: Damage to the nervous system. Some chemotherapy drugs can cause this condition. Symptoms include weakness or tingling in the hands and/or feet.

PET scan (positron emission tomography): PET scans may be used to identify areas in the body that are affected by cancer. This test evaluates metabolic activity in different parts of the body using a radioisotope.

PFT (pulmonary function test): Determines how well one’s lungs are functioning.

Pleura: The 2 membranes, partial pleura and visceral pleura, that line the chest wall and cover the lungs.

Pleurectomy: Surgery that removes the 2 sacs encompassing the lung.

Pleuritic chest pain: Sharp stabbing chest pain that occurs with breathing.

Pneumonectomy: Surgery to remove one lung.

Pneumothorax: Air that escapes from the lung into the pleural space in the chest.

Polyclonal antibodies: When an invader such as a virus, bacteria, or foreign cell enters the body, the immune system produces many different protein molecules called polyclonal antibodies that attack multiple unique sites (called antigens) on each foreign invader.

Primary therapy: The first therapy given after a diagnosis of cancer.

Primary tumor: The original tumor.

Prognosis: The likely outcome of a disease, including the chance of recovery.

Pulmonary artery: The blood vessel that returns oxygen-depleted blood to the lungs.

Pulmonary vein: The blood vessel that carries oxygen-replenished blood from the lungs to the heart so it can be sent throughout the body.

Radiation field: The part of the body that receives radiation therapy.

Radiation therapy: The use of radiation beams (x-rays) to treat a cancer. High doses of high-energy radiation beams, carefully focused on a tumor, will kill cancer cells.

Refractory disease: A cancer that is resistant to treatment.

Regimen: A specific combination of drugs (chemotherapy), their doses, and their schedules of administration. A regimen may also include radiotherapy.

Relapse: The return of cancer after it has been treated and the patient has been in remission.

Remission: The absence of disease. A patient is in remission when the lung cancer has been treated and tumors have diminished by at least 50% (partial) or have disappeared (complete). Remission does not necessarily mean cure.

Resection: Surgery that removes all or part of an organ.

Risk factors: Factors that may increase the chance a person will develop lung cancer.

SCLC: Small cell lung cancer.

Salvage therapies: Therapies that are given if the primary therapy is not successful or if the disease disappears and then comes back.

Scar carcinoma: A subtype of lung cancer that creates a scar-like buckling on the outside of the lung near the tumor.

Segmentectomy: Removal of a segment of one lobe of one lung, its blood supply, and nearby lymph nodes.

Spirometry: The measure of the amount of air that the patient can inhale and exhale from the lungs.

Spleen: An organ on the left side of the upper abdomen, near the stomach. It is a key component of the lymphatic system. The spleen produces and stores lymphocytes and releases them when required as part of the body’s response to infections and other stimuli. The spleen may store blood and remove old blood cells from circulation.

Split-lung function study: A test of each lung’s capacity.

Sputum: Mucus brought from the airways usually by coughing.

Squamous cell carcinoma: A subtype of non-small cell lung cancer (also called epidermoid carcinoma).

Stable disease: The disease does not get better or worse following therapy.

Stage: The extent of cancer in the body, including whether the disease has spread from the original site to other body sites.

Standard therapy: A current primary therapy that has been shown to be effective and safe over time.

Stridor: A harsh vibrating sound heard when airways are blocked.

Synergism: The term used when 2 or more chemotherapy drugs given together provide a better anti-cancer effect than either of the medications alone.

Systemic symptoms: Symptoms that affect the entire body. Examples of these include fever, night sweats, and weight loss.

T-Tube: A plastic tube inserted into an airway to keep it open.

TNM: Three measures of tumor spread, tumor size, lymph nodes affected, and metastatic (distant) sites involved—that are used to stage lung cancer and many other cancers at Levels I through IV.

Thoracic surgeon: A surgeon who has undergone at least 2 additional years of training in order to specialize in heart and lung surgery.

Thoracentesis: Inserting a narrow needle with a larger reservoir through the chest wall for one-time drainage via suction aspiration.

Thrombocytopenia: A shortage of platelets in the blood. This reduces the ability of the blood to clot.

Thymus gland: A gland located behind the sternum (breast bone) that enhances the reproduction and development of lymphocytes.

Toxicity: The unwanted side effects of cancer therapies, such as a decrease in blood cells, nausea and vomiting, and hair loss.

Tumor: An abnormal mass or swelling of tissue. Tumors may occur anywhere in the body. A tumor may be benign (harmless) or malignant (cancerous).

VATS (video-assisted thoracic surgery): This technique uses a camera to guide surgical tools into the lungs and is less invasive than traditional surgery.

Vaccine: Cancer vaccines combine malignant cancer cells with a patient’s own natural defenses to fight the disease. These vaccines are custom-made, using a sample of the tumor that is obtained from each patient’s lymph nodes.

Watchful waiting: An approach where no immediate medical, surgical, or radiation therapy is given—patients are followed closely to make sure the cancer does not progress. Some slow-growing lung tumors are treated with watchful waiting.

Wedge resection: Surgery to remove a wedge of tissue from one lobe of one lung that is usually done only for early-stage disease or isolated tumors.

Xerostomia: A temporary reduction in the production of saliva.

X-ray: High-energy radiation that is used in low doses to provide images of the inside of the body and in high doses to treat cancer.