Lung Glossary

Acquired resistance:  Disease progression after initial benefit with a targeted therapy.

Actionable target: A genetic abnormality for which there are FDA-approved therapies or clinical trials available.

Activating mutation:  A type of genetic mutation that occurs when there is an overexpression, or too much, of the protein a gene makes. This overly active protein leads to uncontrolled cell growth.

Adaptive response:  Specific response of the immune system; creates T cells to respond to a specific antigen on a cancer cell.

Adenocarcinoma:  A type of non-small cell lung cancer that usually develops in the cells lining the lungs. It is the most common type of lung cancer seen in non-smokers.

Adenoids:  A mass of lymphatic tissue located where the nose blends into the throat.

Adenosquamous carcinoma:  A type of cancer that contains two types of cells: squamous cells (thin, flat cells that line certain organs) and gland-like cells.

Adjuvant:  Cancer treatment given after the primary treatment in order to kill unseen cancer cells or to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy or biological therapy.

Adoptive T-cell therapy:  Therapy that involves removing some of a patient’s own immune-system cells—often altering and increasing their ability to recognize and kill cancer cells—growing billions of them in the laboratory and infusing the cultured cells into the patient. The idea is to provide an invading force of immune cells that can attack tumors at a level that the immune system is not capable of doing on its own. Also called “adoptive T-cell therapy.”

Advanced-stage non-small cell lung cancer:  Refers to NSCLC that has spread either locally or to distant parts of the body.

Aldesleukin:  A growth factor for T cells that is used to treat some types of cancer. It is a form of interleukin-2, a cytokine made by leukocytes (white blood cells) that is made in the laboratory. Aldesleukin increases the activity and growth of T lymphocytes.

ALK rearrangement:  Fusion of the ALK gene with another gene, producing an abnormal protein that leads to cancer cell growth.

Alveoli:  Tiny air sacs at the end of the bronchioles (tiny branches of air tubes) in the lungs. The alveoli are where the lungs and the bloodstream exchange carbon dioxide and oxygen. Carbon dioxide in the blood passes into the lungs through the alveoli. Oxygen in the lungs passes through the alveoli into the blood.

Amplification:  A usually massive replication of genetic material, especially of a gene or DNA sequence.

Anaplastic lymphoma kinase (ALK):  A gene that the body normally produces but, when it fuses with another gene, produces an abnormal protein that leads to cancer cell growth.

Anemia:  A condition in which the number of red blood cells is below normal, resulting in pallor and fatigue.

Angiogensis:  The formation of new blood vessels that tumors need to grow. This process is caused by the release of chemicals by the tumor and by host cells near the tumor.

Angiogenesis inhibitors:  Drugs given during cancer treatment to prevent the growth of new blood vessels that tumors need to grow. Also called “antiangiogenesis agents” or “antiangiogenesis drugs.”

Antibody:  A protein made by B cells in response to an antigen. Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

Antigen:  A protein on the surface of a cell that causes the body to make a specific immune response.

Asbestos:  A group of minerals that take the form of tiny fibers. Asbestos has been used as insulation against heat and fire in buildings. Loose asbestos fibers breathed into the lungs can cause several serious diseases, including lung cancer and malignant mesothelioma (cancer found in the lining of lungs, chest or abdomen).

Autoimmune disorder:  A condition in which the body recognizes its own tissues as foreign and directs an immune response against them.

B cell, B lymphocyte:  A type of white blood cell that circulates in the blood and lymph seeking out foreign invaders. Upon meeting a “non-self” antigen, it makes proteins called antibodies, which detect and destroy the antigens.

Benign:  Not cancerous.

Biological therapy:  A type of treatment that uses substances made from living organisms to treat disease. These substances may occur naturally in the body or may be made in the laboratory. Some biological therapies stimulate or suppress the immune system to help the body fight cancer, infection and other diseases. Other biological therapies attack specific cancer cells, which may help keep them from growing or kill them.

Biomarker:  A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment of a disease or condition.

Biopsy:  The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue.

Blood chemistry tests:  A common panel of blood tests that measures the amounts of electrolytes and other chemicals made in the body. It provides information on how the body’s organs, such as kidneys, liver and heart, are functioning.

Blood count:  A measure of the number of red blood cells, white blood cells and platelets in the blood. A complete blood count is used to help diagnose and monitor many conditions. Also called “blood cell count” and “CBC.”

Bone marrow:  The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells and platelets.

Bone scan:  A scan that checks for abnormal areas or damage in the bones. A very small amount of radioactive material is injected into a vein and travels through the blood. The radioactive material collects in the bones and is detected by a special camera that takes pictures of the inside of the body. A bone scan may be used to diagnose bone tumors or cancer that has spread to the bone.

Brachytherapy:  A type of radiation therapy in which radioactive material sealed in needles, seeds, wires or catheters is placed directly into or near a tumor. Also called “internal radiation therapy” and “radiation brachytherapy.”

Bronchi:  The large air passages that lead from the trachea (windpipe) to the lungs.

Bronchiole:  A tiny branch of air tubes in the lungs that narrow down from the bronchus and connect to the alveoli (air sacs).

Bronchitis:  Inflammation and irritation of the bronchi, the tubes that carry air to the lungs; symptoms include cough and fatigue.

Bronchoscopy:  A procedure that uses a bronchoscope to examine the inside of the trachea, bronchi and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue; this tissue can then be checked under a microscope for signs of disease. The bronchoscope is inserted through the nose or mouth.

Bronchus:  A large airway that leads from the trachea (windpipe) to a lung. The plural of bronchus is bronchi.

Cancer:  A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems.

Carcinoid tumor:  A slow-growing type of tumor usually found in the gastrointestinal system (most often in the appendix), and sometimes in the lungs or other sites.

Carcinogen:  Any substance that causes cancer.

Carcinoma:  Cancer that begins in the skin or in tissues that line or cover internal organs.

Caregiver:  Caregivers are volunteers who provide physical and emotional care to a loved one with lung cancer. They may be spouses, partners, family members or close friends. 

CAT scan:  A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create three-dimensional (3-D) views of tissues and organs. A dye may be injected into a vein or swallowed to help the tissues and organs show up more clearly. Also called “CAT scan” and “computed tomography scan.”

Cavity:  A hollow area or hole. It may describe a body cavity (such as the space within the abdomen or chest) or a hole in a tooth caused by decay.

Cerebrospinal fluid:  The fluid that flows in and around the hollow spaces of the brain and spinal cord and between two of the meninges (the thin layers of tissue that cover and protect the brain and spinal cord).

Cervical lymph nodes: Lymph nodes found in the neck.

Chemoprevention:  The use of drugs, vitamins or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer.

Chemoradiation:  Treatment that combines chemotherapy with radiation therapy. Also called “chemoradiotherapy.”

Chemotherapy:  Treatment with drugs that kill cancer cells.

Chest X-ray:  A type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.

Clinical trial:  A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called “clinical research trial” or “clinical research study.”

Colony-stimulating factors:  Drugs that assist the bone marrow in producing different types of white blood cells. They are given to help support white blood cell levels and to strengthen the immune system after chemotherapy. Colony-stimulating factors include granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF).

Combination therapy:  The use of two or more types of treatments at the same time to treat a disease or condition; most often refers to two or more drugs used together.

Complementary therapies:  Treatments that are used along with standard treatments but are not considered standard. Standard treatments are based on the results of scientific research and are currently accepted and widely used. Less research has been done for most types of complementary medicine. Complementary medicine includes acupuncture, dietary supplements, massage therapy, hypnosis and meditation. For example, acupuncture may be used with certain drugs to help lessen cancer pain or nausea and vomiting.

Complete blood count:  A measure of the number of red blood cells, white blood cells and platelets in the blood. A complete blood count is used to help diagnose and monitor many conditions. Also called “blood cell count” and “CBC.”

Complete response:  The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called “complete remission.”

Concurrent:  At the same time.

Contrast:  A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema or by mouth. Contrast material may be used with x-rays, CT scans, MRI or other imaging tests.

Control group:  In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

Core biopsy:  The removal of a tissue sample with a wide needle for examination under a microscope. Also called “core needle biopsy.”

Curative treatment:  Treatment that is meant to cure the disease itself as opposed to masking the symptoms; in the case of lung cancer, killing or removing all lung cancer cells.

Cytokine:  A type of protein that is made by certain immune and non-immune cells and has an effect on the immune system. Some cytokines stimulate the immune system, and others slow it down.

Data and Safety Monitoring Board (DSMB):  An impartial group that oversees a clinical trial and reviews the results to see if they are acceptable. This group determines if the trial should be changed or closed.

Disease-free survival (DFS):  The length of time that the patient survives without any signs or symptoms of that cancer, after primary treatment for a cancer ends. In a clinical trial, measuring the effect on disease-free survival is one way to see how well a new treatment works.

Disease progression:  Continued growth or spread of cancer.

Echinoderm microtubule-associated protein like 4 (EML4):  A gene that, when combined with the anaplastic lymphoma kinase (ALK) gene, produces an abnormal protein that leads to cancer cell growth.

Efficacy:  The ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.

EGFR mutation:  A change in the gene that controls production of epidermal growth factor receptor (EGFR), resulting in overexpression of EGFR.

Elevated transaminases:  Higher than normal levels of enzymes found in the liver that may indicate liver disease.

Endocrine gland:  A gland (for example, the thyroid or the pituitary) that produces an endocrine secretion.

Endoscope:  A thin, tube-like instrument used to look at tissues inside the body. An endoscope has a light and a lens for viewing, and may have a tool to remove tissue.

Enzyme:  Special proteins that the body produces to control its cells and carry out chemical reactions quickly. Sometimes enzymes signal cancer cells to grow.

Enzyme inhibitors:  A type of targeted cancer therapy that works by blocking the signals an enzyme sends cancer cells to grow.

Epidermal growth factor receptor:  The protein found on the surface of some cells and to which epidermal growth factor binds, causing the cells to divide. It is found at abnormally high levels on the surface of many types of cancer cells, so these cells may divide excessively in the presence of epidermal growth factor.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors:  Drugs that block the activity of a protein called epidermal growth factor receptor (EGFR). Blocking EGFR may keep cancer cells from growing. Also called “EGFR inhibitor” and “epidermal growth factor receptor inhibitor.”

Epidermoid carcinoma:  Cancer that begins in squamous cells. Also called squamous cell carcinoma. When it starts in the lungs, it is considered a type of non-small cell lung cancer.

Epithelial cells:  The cells that line the internal and external surfaces of the body. In the lungs, they line the airways and make mucus to lubricate and protect the lungs.

Erythropoiesis-stimulating agents:  Drugs that stimulate the bone marrow to produce red blood cells; approved for the treatment of anemia due to chemotherapy, chronic kidney failure, and for reducing the number of blood transfusions during and after certain major surgeries. Erythropoiesis-stimulating agents include epoetin alfa (Procrit and Epogen) and darbepoetin alfa (Aranesp).

Event-free survival (EFS):  In cancer, the length of time after primary treatment for a cancer ends that the patient remains free of certain complications or events that the treatment was intended to prevent or delay. These events may include the return of the cancer or the onset of certain symptoms, such as bone pain from cancer that has spread to the bone. In a clinical trial, measuring the effect on event-free survival is one way to see how well a new treatment works and how well a patient can tolerate the side effects.

Extensive-stage small cell lung cancer:  Cancer that has spread widely throughout a lung, to the other lung, to lymph nodes on the other side of the chest, or to distant organs. Many doctors also call cancer that has spread to the fluid around the lung “extensive stage.”

External beam radiation therapy (EBRT):  A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body.

Fine needle aspiration (FNA):  The removal of tissue or fluid with a thin needle for examination under a microscope, usually to determine if cancer is present or what the cancer cell type is.

First-line clinical trial:  A clinical trial for a patient who has never been treated before.

First-line treatment or therapy:  The first treatment given for a disease. It is often part of a standard set of treatments, such as surgery followed by chemotherapy and radiation. When used by itself, first-line therapy is the one accepted as the best treatment. If it doesn’t cure the disease or it causes severe side effects, other treatment may be added or used instead.

Floater:  A bit of optical debris (as a dead cell or cell fragment) in the vitreous body or lens of the eye that may be perceived as a spot before the eye.

Fluoroscope:  An instrument equipped with a fluorescent screen on which the internal structures of the human body may be continuously viewed by means of X-ray. Often used by a surgeon to perform a transthoracic needle biopsy.

Foreign:  In medicine, this term describes something that comes from outside the body. A foreign substance in the body’s tissues, such as a bacterium or virus, may be recognized by the immune system as not belonging to the body. This causes an immune response. Other foreign substances in the body, such as artificial joints, are designed to not cause an immune response.

Fusion:  A gene made by joining parts of two different genes. Once fused together, they produce an abnormal protein that promotes abnormal, unchecked cell growth.

General anesthesia:  Medicine that puts the patient in a deep sleep.

Genes:  Coded instructions within a cell that control how the cell grows in a systematic and precise way.

Genetic mutation:  Any change in the gene sequence of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to gene-damaging agents in the environment. Certain mutations may lead to cancer or other diseases.

Genetic testing:  Analyzing DNA to look for a genetic alteration that may indicate an increased risk for developing a specific disease or disorder.

Helical CT scan:  A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. It continuously rotates in a spiral motion and takes several three-dimensional, very detailed X-rays of the lungs in a short amount of time. Also called “spiral CT scan.”

Histology:  The study of tissues and cells under a microscope.

Hospice:  A program that provides special care for people who are near the end of life and for their families, either at home, in freestanding facilities, or within hospitals.

IL-2:  One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. IL-2 is made by a type of T lymphocyte. It increases the growth and activity of other T lymphocytes and B lymphocytes, and it affects the development of the immune system.

Imaging test:  Any test that uses a form of energy, such as X-rays, ultrasounds, radio waves or radioactive substances, to make detailed pictures of areas inside the body. Imaging tests include CT scans, MRI scans and nuclear medicine tests.

Image-guided radiation therapy:  A procedure that uses a computer to create a picture of a tumor to help guide the radiation beam during radiation therapy. The pictures are made using CT, ultrasound, X-ray or other imaging techniques. Image-guided radiation therapy makes radiation therapy more accurate and causes less damage to healthy tissue.

Immune checkpoint inhibitors:  Agents that target the pathways tumor cells use to evade recognition and destruction by the immune system.

Immune response:  The activity of the immune system against foreign substances (antigens).

Immune system:  A complex network of cells, tissues, organs and the substances they make that helps the body fight infections and other diseases. The immune system includes white blood cells and organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels and bone marrow.

Immunotherapy:  A type of cancer therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection and other diseases. Some types of immunotherapy target only certain cells of the immune system. Others affect the immune system in a general way.

Inhibitor:  Any substance that interferes with a chemical reaction, growth or other biologic activity; for example, an EGFR inhibitor blocks the activity of epidermal growth factor receptors in promoting cancer growth.

Innate immunity:  Immune response to a pathogen that involves the pre-existing defenses of the body. Such a response is not specific to a pathogen.

In situ: In its original place. For example, in “carcinoma in situ,” abnormal cells are found only in the place where they first formed. They have not spread.

Instructional review board (IRB):  A group of scientists, doctors, clergy and patient advocates that reviews and approves the detailed plan for every clinical trial. Institutional review boards are meant to protect the people who take part in a clinical trial. They check to see that the trial is well designed, legal, and ethical; does not involve unneeded risks; and includes a safety plan for patients. There is an institutional review board at every healthcare facility that does clinical research.

Intensity-modulated radiation therapy (IMRT):  A type of three-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor.

Interstitial lung disease:  A group of disorders that cause scarring of the lungs, which eventually affects patients’ ability to get enough oxygen into their bloodstream and to breathe.

Interventional radiologist:  A medical doctor who is specially trained to use minimally invasive image-guided procedures to diagnose and treat diseases, with the goal of minimizing risk to the patient and improving health outcomes.

Intradermal:  Within the skin; also called “intracutaneous.”

Intramuscualar (IM):  Within a muscle.

Intravenous (IV):  Into or within a vein. Intravenous usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called IV.

Investigational group:  In a treatment clinical trial, the group that receives the new treatment being studied. This group is compared to the group that does not receive the new treatment, to see if the new treatment works.

Irradiate:  To treat with radiation.

Large cell carcinoma:  Lung cancer in which the cells are large and look abnormal when viewed under a microscope.

Lesion:  An area of abnormal tissue, which may be benign or malignant.

Leukaphersis:  Removal of the blood to collect specific blood cells. The remaining blood is returned to the body.

Limited stage small cell lung cancer:  Cancer that is in the lung where it started and may have spread to the area between the lungs or to the lymph nodes above the collarbone.

Lobe:  A portion of an organ.

Lobectomy:  Surgery to remove a whole lobe of the lung.

Locally advanced non-small cell lung cancer:  NSCLC that has spread from where it started to nearby tissue or lymph nodes.

Low-dose CT scan (LDCT):  A newer form of CT scan that uses less radiation than a standard chest CT and takes less than one minute to complete. It continuously rotates in a spiral motion and takes several three-dimensional, very detailed X-rays of the lungs. This type of CT uses no dyes and no injections, and requires nothing to swallow by mouth. Also known as “low-dose spiral [or helical] CT scan.”

Lymph:  The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

Lymph node, lymph gland:  A rounded mass of lymphatic tissue surrounded by a capsule of connective tissue. Lymph nodes filter lymph, the clear fluid that carries cells to fight infections and other diseases, and store lymphocytes (white blood cells).

Lymphatic vessels:  Thin-walled tubular structures that collect and filter lymph fluid before transporting it back to the blood circulation. Also called “lymph vessels.”

Lymphocyte:  A type of white blood cell that is made in the bone marrow and is found in the blood and in lymph tissue. The main types of lymphocytes are B cells, T cells and NK cells.

Malignant:  Cancerous.

Maintenance therapy:  Treatment that is given to help keep cancer from growing after it has shrunk or stabilized following initial therapy. It may include treatment with drugs, vaccines, or antibodies that kill cancer cells, and it may be given for a long time.

Margin:  The edge or border of the tissue removed in cancer surgery. The margin is described as “negative” or “clean” when the pathologist finds no cancer cells at the edge of the tissue, suggesting that all of the cancer has been removed. The margin is described as “positive” or “involved” when the pathologist finds cancer cells at the edge of the tissue, suggesting that not all of the cancer has been removed.

Medistinal:  Relating to the mediastinum (area between the lungs).

Medistinoscopy:  A procedure performed under general anesthesia to get a look at the area between the lungs, or mediastinum. A small incision is made above the breastbone, and a thin tube with a lens for viewing and a tool to remove tissue is inserted. The samples are sent to the lab to check for cancer cells.

Mediastinum:  The space in the chest that is between the lungs. The organs in this area include the heart and its large blood vessels, the trachea, the esophagus, the thymus and lymph nodes, but not the lungs.

Metastatic:  Having to do with metastasis.

Metastasis:  The spread of cancer from the primary site, or place where it started, to other places in the body.

Molecular profile:  The genetic characteristics, as well as any other unique biomarkers, found in a person’s cancer. The information is used to identify and create targeted therapies that are designed to work for a specific cancer tumor profile.

Monoclonal antibody:  A type of protein made in the laboratory that can bind to substances in the body, including cancer cells. There are many kinds of monoclonal antibodies. A monoclonal antibody is made so that it binds to only one substance. Monoclonal antibodies are being used to treat some types of cancer. They can be used alone or to carry drugs, toxins or radioactive substances directly to cancer cells.

Monotherapy:  The use of a single drug to treat a particular disorder or disease.

MRI scan:  A scan that provides detailed pictures of areas inside the body by using radio waves and strong magnets that a computer translates into an image. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints and the inside of bones. Also called “magnetic resonance imaging.”

Mucin:  A protein produced by some cancer cells, including adenocarcinoma.

Multiplex testing:  The testing for multiple molecular genetic mutations at one time.

National Lung Screening Trial (NLST):  National Institutes of Health-funded clinical trial that found using a low-dose CT scan to screen for lung cancer can reduce mortality due to lung cancer.

Natural killer (NK) cells:  A type of white blood cell that patrols the body and is on constant alert, seeking foreign invaders. Once NK cells recognize a cell as abnormal, they release granules (small particles) with enzymes that can kill tumor cells or cells infected with a virus

NED:  Acronym for “no evidence of disease.”

Neoadjuvant:  Treatment given prior to the main treatment in order to shrink a tumor. Examples of neoadjuvant therapy include chemotherapy and/or radiation therapy prior to surgery.

Neoplasm:  An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Neoplasms may be benign (not cancer) or malignant (cancer). Also called “tumor.”

Neuropathy:  A nerve problem that causes pain, numbness, tingling, swelling or muscle weakness in different parts of the body. It usually begins in the hands or feet and gets worse over time. Neuropathy may be caused by cancer or cancer treatment, such as chemotherapy or surgery. May also be called “peripheral neuropathy.”

Neutropenia:  A condition in which there are fewer than normal neutrophils (a type of white blood cell), leading to increased susceptibility to infection.

Nodule:  A growth or lump that may be malignant (cancer) or benign.

Non-contrast:  Refers to an imaging test that does not make use of contrast agent.

Non-small cell lung cancer (NSCLC):  A group of lung cancers that are named for the kinds of cells found in the cancer and how the cells look under a microscope. The three main types of non-small cell lung cancer are squamous cell carcinoma, large cell carcinoma and adenocarcinoma. Non-small cell lung cancer is the most common kind of lung cancer.

Oncologist:  A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer or cancer treatment. For example, a thoracic oncologist specializes in treating lung, esophageal, pleural, mediastinal and chest wall tumors. A medical oncologist specializes in treating cancer with chemotherapy. A radiation oncologist specializes in treating cancer with radiation.

Overall survival:  The length of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that patients diagnosed with the disease remain alive. In a clinical trial, measuring the effect on overall survival is one way to see how well a new treatment works.

Overexpression:  The expression of too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.

Palliative care:  Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal is to provide patients with relief from the symptoms, pain and stress of a serious illness. Also called “palliation,” “comfort care” and “supportive care.”

Pancoast tumor:  A type of lung cancer that begins in the upper part of a lung and spreads to nearby tissues such as the ribs and vertebrae. Most pancoast tumors are non-small cell cancers. Also called “pulmonary sulcus tumor.”

Partial response:  A decrease of at least 30 percent in the size of a tumor or in the extent of cancer in the body in response to treatment. Also called “partial remission.”

Pathologist:  A doctor who identifies diseases by studying cells and tissues under a microscope or with other equipment.

Pathology report:  The description of cells and tissues made by a pathologist based on what is seen under a microscope. This is sometimes used to make a diagnosis of lung cancer or another disease. May also be referred to in short form as “path report” or even “the path.”

Patient navigator:  Someone who provides personal guidance to patients as they move through the healthcare system. Patient navigators may have professional medical, legal, financial or administrative experience. Other navigators may have personally faced healthcare-related challenges and want to help others in similar situations. Navigators can be employed by community groups, hospitals or insurance companies. They may be paid by those organizations, they may be volunteers, or they may be independent consultants hired by people who want help managing their complex medical needs.

PD-1/PD-L1, programmed death 1/programmed death 1 ligand:  Part of the immune system mechanism that keeps T cells from functioning.

Pelvic inflammatory disease:  A condition in which the female reproductive organs are inflamed. It may affect the uterus, fallopian tubes, ovaries, and certain ligaments. Pelvic inflammatory disease is usually caused by a bacterial infection. It may cause infertility and an increased risk of an ectopic pregnancy (pregnancy in the fallopian tubes). Also called “PID.”

Perforation:  A hole that develops through the whole wall of the esophagus, stomach, small intestine, large bowel, rectum or gallbladder.

Performance status:  A measure of how well a patient is able to perform ordinary tasks and carry out daily activities.

Periphery:  The outermost part or region within a precise boundary.

PET-CT scan:  A special scan that is able to do a positron emission tomography (PET) scan and a computed tomography (CT) scan at the same time. It allows the doctor to compare areas of radioactivity on the PET with the more detailed appearance of that area on the CT. Also called “positron emission tomography-computed tomography scan.”

PET scan:  A scan in which a small amount of radioactive sugar is injected into a vein and a special camera creates a picture of areas in the body where the sugar is taken up. Because cancer cells often take up more sugar than normal cells, the PET scan is used to find cancer cells in the body. Also called “positron emission tomography scan.”

Phase I research study:  A study in which researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range and identify side effects.

Phase II research study:  A study in which the drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.

Phase III research study:  A study in which the drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely. Once Phase III is completed, the drug or treatment can be submitted to the US Food and Drug Administration (FDA) for approval.

Photdynamic therapy (PDT):  Treatment with drugs that become active when exposed to light. These activated drugs may kill cancer cells.

Phlegm:  Thick mucus made by the cells lining the upper airways and lungs.

Platelet:  Type of blood cell responsible for blood clotting. Platelets are found in the blood and spleen.

Pleomorphic:  Occurring in various distinct forms; in terms of cells, having variation in the size and shape of cells or their nuclei.

Pleura:  A thin layer of tissue that cover the lungs and lines the inside wall of the chest cavity. It protects and cushions the lungs. The fluid it secretes allows the lungs to move smoothly in the chest cavity while a person is breathing.

Pleural cavity:  The space enclosed by the pleura, a thin layer of tissue that covers the lung and lines the inside wall of the chest cavity.

Pleural effusion:  Fluid around the lungs.

Pneumonectomy:  Surgery to remove an entire lung.

Pneomonia:  A severe inflammation of all or part of the lungs in which the tiny air sacs called alveoli are filled with fluid. Symptoms include cough, fever and trouble breathing.

Pneumonitis: Inflammation of the lungs that may be caused by disease, infection, radiation or other therapy, allergy, or irritation of lung tissue by inhaled substance.

Pneumothorax:  An abnormal collection of air or gas in the space between the lung and the chest wall.

Primary tumor:  A term used to describe the original, or first, tumor in the body.

Prognosis:  The likely outcome or course of a disease; the chance of recovery or recurrence.

Progression-free survival (PFS):  The length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse. In a clinical trial, measuring the effect on progression-free survival is one way to see how well a new treatment works.

Progressive disease:  An increase of at least 20 percent in the size of a tumor or in the extent of cancer in the body.

Proliferating:  Multiplying or increasing in number.

Prophylactic cranial irradiation:  Radiation therapy to the brain to reduce the risk of cancer spreading to that organ.

Protein:  A molecule made up of amino acids needed for the body to function properly. Proteins are the basis of body structures, such as skin and hair, and of other substances such as enzymes, cytokines and antibodies.

Protocol:  A detailed plan of a scientific or medical experiment, treatment or procedure. In clinical trials, it states what the study will do, how it will be done and why it is being done. It explains how many people will be in the study, who is eligible to take part in it, what study drugs or other interventions will be given, what tests will be done and how often, and what information will be collected.

Proton:  A small, positively charged particle of matter found in the atoms of all elements.

Proton therapy:  A type of radiation therapy that uses streams of protons (tiny particles with a positive charge) to kill tumor cells. This type of treatment can reduce the amount of radiation damage to healthy tissue near a tumor. It is used to treat cancers of the head and neck and organs such as the brain, eye, lung, spine and prostate.

Pruritus:  Itching of the skin.

Pseudoprogression:  Growth in tumor size that is due to response to treatment and not to growth of cancer cells.

Pulmonary rehabilitation:  Behavior and lifestyle changes to help patients with chronic lung disease decrease breathing problems, return to daily activities and improve quality of life. Education may include instruction about breathing exercises, nutrition, use of medicines, and ways for the patient to reduce stress and save energy.

Pulmonologist:  A doctor who specializes in lung disease.

Radiation oncologist:  A doctor who specializes in using radiation to treat cancer.

Radiation therapy:  The use of high-energy radiation from x-rays, gamma rays, neutrons, protons and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, or brachytherapy). Also called “irradiation” and “radiotherapy.”

Radon:  A radioactive gas that is released by uranium, a substance found in soil and rock. Breathing in too much radon can damage lung cells and may lead to lung cancer.

Recurrent lung cancer:  Lung cancer that has come back after a period of time during which the cancer could not be detected. The lung cancer may come back in the lung near the original tumor, in lymph nodes or in a distant organ.

Regional chemotherapy:  Treatment with anticancer drugs directed to a specific area of the body.

Ralapse-free survival:  In lung cancer, the length of time after primary treatment for the cancer ends that the patient survives without any signs or symptoms of that cancer. In a clinical trial, measuring the relapse-free survival is one way to see how well a new treatment works. Also called “DFS,” “disease-free survival” and “RFS.”

Relative survival rate:  A way of comparing the survival of people who have a specific disease with those who don’t, over a certain period of time (usually 5 years) from the date of diagnosis or the start of treatment for those with the disease. It is calculated by dividing the percentage of patients with the disease who are still alive at the end of the period of time by the percentage of people in the general population of the same sex and age who are alive at the end of the same time period. The relative survival rate shows whether the disease shortens life.

Resectable:  Able to be removed by surgery.

Respiratory tract:  The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi and lungs. Also called “respiratory system.”

Restaging:  Staging lung cancer after a recurrence.

Segmentectomy:  Surgical removal of a section of a lobe of the lung. Also called “segmental resection.”

Sleeve resection:  Surgery to remove a lung tumor that is in a lobe of the lung and in the main bronchus, or airway. The tumor is removed, and the ends of the bronchus are rejoined and any remaining lobes are reattached to the bronchus. This surgery is done to save part of the lung. Also called “sleeve lobectomy.”

Small cell lung cancer (SCLC):  A fast-growing cancer that forms in tissues of the lung and can spread to other parts of the body. Named “small” for how the cancer cells look under a microscope.

Spirometer:  An apparatus for measuring the movement of air into and out of the lungs.

Sputum cytology:  Examination under a microscope of cells found in sputum brought up from the lungs by coughing. The test checks for abnormal cells, such as lung cancer cells.

Squamous cell carcinoma:  A type of non-small cell lung cancer that usually starts near a central bronchus. It begins in squamous cells, which are thin, flat cells that look like fish scales.

Stereotactic body radiation therapy (SBRT):  A type of external radiation therapy that uses special equipment to position a patient and precisely deliver extremely high doses of radiation to the tumor while decreasing the dose to healthy tissue nearby. Instead of giving small doses of radiation each day for several weeks, SBRT can be given in two to five treatments.

Sterotactic radiosurgery (SRS):  A type of stereotactic body radiation therapy that is given in a single large dose of radiation to a tumor.

Support group:  A group of individuals sharing similar experiences providing help such as listening, storytelling and resources.

Targeted cancer therapies:  A type of treatment that uses drugs to attack specific types of cancer cells with less harm to normal cells. Some targeted therapies block the action of certain enzymes, proteins or other molecules involved in the growth and spread of cancer cells.

Therapeutic cancer vaccine:  A type of treatment, using a vaccine that is usually made from a patient’s own tumor cells or from substances taken from tumor cells. A cancer vaccine may help the immune system kill cancer cells.

Thorcentesis:  Removal of fluid from around the lungs through a hollow needle inserted between the ribs.

Thoracic surgeon:  A surgeon specially trained in operating on people with lung cancer.

Thorocotomy:  An incision made between the ribs in the side of the chest to open up the chest. This surgery is used to examine the lung and to remove tumor, surrounding tissue and nearby lymph nodes.

Three-dimensional conformal radiation therapy (3D-CRT):  A form of external radiation therapy that uses special computers to precisely map the location of the tumor. Radiation beams are shaped and aimed at the tumor from several directions, which makes it less likely to damage normal tissues.

Thrombocytopenia:  A condition in which there are fewer platelets in the blood than normal. It may result in easy bruising and excessive bleeding from wounds or bleeding in mucous membranes and other tissues.

Trachea:  The airway that leads from the larynx (voice box) to the bronchi (large airways that lead to the lungs). Also called “windpipe.”

Transthoracic needle biopsy:  A procedure in which an interventional radiologist inserts a needle into the chest wall to remove fluid or tissue.

Tyrosine kinase inhibitors:  A type of targeted therapy that blocks the action of enzymes called tyrosine kinases in order to keep cancer cells from growing. Also called “TKIs.”

Wedge resection:  Surgery to remove a triangle-shaped slice of tissue. It may be used to remove a tumor and a small amount of normal tissue around.

Wheezing:  A whistling-type noise that may occur while breathing because of narrowing of the small airways of the lungs.