Cancer Glossary - P

P-30 protein  

An anticancer drug that may inhibit cancer cell growth.

P-32  

A radioactive form of phosphorus used in the treatment of cancer.

p-value  

A statistics term. A measure of probability that a difference between groups during an experiment happened by chance. For example, a p-value of .01 (p = .01) means there is a 1 in 100 chance the result occurred by chance. The lower the p-value, the more likely it is that the difference between groups was caused by treatment.

p53 gene  

A tumor suppressor gene that normally inhibits the growth of tumors. This gene is altered in many types of cancer.

paclitaxel  

An anticancer drug that belongs to the family of drugs called mitotic inhibitors.

Paget's disease of the nipple  

A form of breast cancer in which the tumor grows from ducts beneath the nipple onto the surface of the nipple. Symptoms commonly include itching ad burning and an eczema-like condition around the nipple, sometimes accompanied by oozing or bleeding.

pain threshold  

The point at which a person becomes aware of pain.

PALA  

An anticancer drug that is being studied to increase the effectiveness of the chemotherapy drug fluorouracil.

palate  (PAL-et)

The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).

palliative therapy  

Treatment given to relieve symptoms caused by advanced cancer. Palliative therapy does not alter the course of a disease but can improve the quality of life.

palpable disease  

A term used to describe cancer that can be felt by touch, usually present in lymph nodes, skin, or other organs of the body such as the liver or colon.

palpation  

Examination by pressing on the surface of the body to feel the organs or tissues underneath.

pamidronate  

A drug that belongs to the family of drugs called bisphosphonates. Pamidronate is used as treatment for abnormally high levels of calcium in the blood.

panacea  

A cure-all.

Pancoast tumor  

Non-small cell lung cancer that originates in the upper portion of the lung and extends to other nearby tissues such as the ribs and vertebrae. Also called a pulmonary sulcus tumor.

pancreas  

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

pancreatectomy  (pan-kree-a-TEK-toe-mee)

Surgery to remove the pancreas. In a total pancreatectomy, a portion of the stomach, the duodenum, common bile duct, gallbladder, spleen, and nearby lymph nodes also are removed.

pancreatic  

Having to do with the pancreas.

pancreatic cancer  

A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called exocrine cancer.

pancreatic ducts  

A system of ducts in the pancreas. Pancreatic juices containing enzymes are released into these ducts and flow into the small intestine.

pancreatic enzymes  

A group of proteins secreted by the pancreas that aid in the digestion of food.

pancreatic juices  

Fluids made by the pancreas. Pancreatic juices contain proteins called enzymes that aid in digestion.

pancreatitis  

Inflammation of the pancreas. Chronic pancreatitis may cause diabetes and problems with digestion. Pain is the primary symptom.

PAP  

Prostatic acid phosphatase. An enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer.

PAP smear  

The collection of cells from the cervix for examination under a microscope. It is used to detect changes that may be cancer or may lead to cancer, and can show noncancerous conditions, such as infection or inflammation. Also called a Pap test.

Pap test  

The collection of cells from the cervix for examination under a microscope. It is used to detect changes that may be cancer or may lead to cancer, and can show noncancerous conditions, such as infection or inflammation. Also called a Pap smear.

papillary serous carcinoma  

An aggressive cancer that usually affects the uterus/endometrium, peritoneum, or ovary.

papillary thyroid cancer  (PAP-i-lair-ee)

Cancer that develops from cells in the thyroid and forms small finger-like projections. The most common type of thyroid cancer, it grows slowly, is more common in women than in men, and often develops before age 40.

papillary tumor  (PAP-ih-lar-ee TOO-mer)

A tumor shaped like a small mushroom, with its stem attached to the epithelial layer (inner lining) of an organ.

papilledema  (pap-il-eh-DEE-ma)

Swelling around the optic disk.

paracentesis  

Insertion of a thin needle or tube into the abdomen to remove fluid from the peritoneal cavity.

parageusia  

A bad taste in the mouth. Also called dysgeusia.

paralysis  (pa-RAL-ih-sis)

Loss of ability to move all or part of the body.

paramyxovirus  

A type of virus that has hemagglutinin-neuraminidase proteins in the outer coat and RNA as the genetic material. Measles (rubeola) virus, mumps virus, and Newcastle disease virus are paramyxoviruses.

paraneoplastic syndrome  (pair-a-nee-o-PLAS-tik)

A group of symptoms that may develop when substances released by some cancer cells disrupt the normal function of surrounding cells and tissue.

parasite  

An animal or a plant that lives on or in an organism of another species and gets at least some of its nutrients from it.

parasitic  

Having to do with or being a parasite.

parathyroid glands  (pair-a-THIGH-roid)

Four pea-sized glands found on the thyroid. The parathyroid hormone produced by these glands increases the calcium level in the blood.

parathyroid hormone  (par-a-THI-royd)

A substance made by the parathyroid gland that helps the body store and use calcium. Also called parathormone, parathyrin, or PTH.

parenchyma  (pah-REN-kih-ma)

The essential or functional elements of an organ.

paresthesias  

Abnormal touch sensations, such as burning or prickling, that occur without an outside stimulus.

Parkinson's disease  

A progressive disorder of the nervous system marked by muscle tremors, muscle rigidity, decreased mobility, stooped posture, slow voluntary movements, and a mask-like facial expression.

parotidectomy  

Surgery to remove all or part of the parotid gland (a large salivary gland located in front of and just below the ear). In a radical parotidectomy, the entire gland is removed.

paroxetine hydrochloride  

An antidepressant drug.

partial cystectomy  (sis-TEK-to-mee)

The removal of the cancer as well as some of the bladder tissue around the tumor. Also called segmental cystectomy.

partial mastectomy  

The removal of a cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor. Usually some of the lymph nodes under the arm are also taken out. Also called segmental mastectomy.

partial remission  

A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment. Also called partial response.

partial response  

A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment.

passive antibody therapy  

Treatment with injections of antibodies made in another animal or in the laboratory.

pathologic fracture  

A broken bone caused by disease, often by the spread of cancer to the bone.

pathologist  (pa-THOL-o-jist)

A doctor who identifies diseases by studying cells and tissues under a microscope.

pathology report  

The description of cells and tissues made by a pathologist based on microscopic evidence, and sometimes used to make a diagnosis of a disease.

patient advocate  

A person who helps a patient work with others who have an effect on the patient's health, including doctors, insurance companies, employers, case managers, and lawyers. A patient advocate helps resolve issues about health care, medical bills, and job discrimination related to a patient's medical condition. Cancer advocacy groups try to raise public awareness about important cancer issues, such as the need for cancer support services, education, and research. Such groups work to bring about change that will help cancer patients and their families.

patient-controlled analgesia  

PCA. A method in which the patient controls the amount of pain medicine that is used. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump that is connected to a small tube in the body.

PCA  

Patient-controlled analgesia. A method in which the patient controls the amount of pain medicine that is used. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump that is connected to a small tube in the body.

PDQ  

Physician Data Query. PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information is available on the Cancer.gov Web site. More specific information about PDQ can be found at http://cancer.gov/cancer_information/pdq/.

peau d'orange  

A dimpled condition of the skin of the breast, resembling the skin of an orange, sometimes found in inflammatory breast cancer.

pediatric  (pee-dee-AT-rik)

Having to do with children.

pedigree  

A record of one's ancestors, offspring, siblings, and their offspring that may be used to determine the pattern of certain genes or disease inheritance within a family.

PEG-interferon alfa-2b  

An anticancer drug that belongs to the family of drugs called biological response modifiers. PEG-interferon alfa-2b is a cytokine. Also called SCH 54031.

PEG-MGDF  

A synthetic form of a protein that is normally made in the body to regulate the production of platelets.

pegaspargase  

A modified form of asparaginase, an anticancer drug that belongs to the family of drugs derived from enzymes.

PEITC  

Phenethyl isothiocyanate. A naturally occurring compound found in some cruciferous vegetables. It is being studied as an agent to prevent cancer.

peldesine  

A substance that is being studied for the treatment of cancer.

pelvic  

Having to do with the pelvis (the lower part of the abdomen located between the hip bones).

pelvis  

The lower part of the abdomen, located between the hip bones.

pemetrexed disodium    

An anticancer drug that belongs to the family of drugs called enzyme inhibitors. Also called LY231514.

penclomedine  

An anticancer drug that belongs to the family of drugs called alkylating agents.

penicillamine  

A drug that removes copper from the body and is used to treat diseases in which there is an excess of this metal. It is also being studied as a possible angiogenesis inhibitor in brain tumors.

penicillin  

An antibiotic drug used to treat infection.

pentetic acid calcium  

A drug that protects healthy tissues from the toxic effects of anticancer drugs.

pentosan polysulfate  

A drug used to relieve pain or discomfort associated with chronic inflammation of the bladder. It is also being evaluated for its protective effects on the gastrointestinal tract in people undergoing radiation therapy.

pentostatin  

An anticancer drug that belongs to the family of drugs called antimetabolites.

pentoxifylline  

A drug used to prevent blood clotting and as a treatment that may help decrease weight loss in people with cancer.

peptide  

Any compound consisting of two or more amino acids, the building blocks of proteins. Peptides are combined to make proteins.

peptide 946  

A protein that causes white blood cells to recognize and destroy melanoma cells.

percutaneous ethanol injection  (per-kyoo-TAY-nee-us)

An injection of ethanol (alcohol) through the skin directly into the tumor to kill cancer cells.

percutaneous transhepatic cholangiography  (per-kyoo-TAY-nee-us trans-heh-PAT-ik ko-LAN-jee-AH-gra-fee)

PTC. A procedure to x-ray the hepatic and common bile ducts. A contrasting agent is injected into the liver or bile duct, and the ducts are then x-rayed to find the point of obstruction.

performance status  

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

perfusion  

Bathing an organ or tissue with a fluid. In regional perfusion, a specific area of the body (usually an arm or a leg) receives high doses of anticancer drugs through a blood vessel. Such a procedure is performed to treat cancer that has not spread.

perfusion magnetic resonance imaging  

A type of magnetic resonance imaging (MRI) used to check the flow of blood to normal tissue and diseased tissue.

pericardial effusion  

An abnormal collection of fluid inside the sac that covers the heart.

perifosine  

An anticancer drug that belongs to the family of drugs called alkylphospholipids.

perillyl alcohol  

A drug used in cancer prevention that belongs to the family of plant drugs called monoterpenes.

perimenopausal  

The time of a woman's life when menstrual periods become irregular. Refers to the time near menopause.

perineal prostatectomy  (peh-rih-NEE-al pros-ta-TEK-toe-mee)

Surgery to remove the prostate through an incision made between the scrotum and the anus.

perineural  (pear-ih-NOOR-al)

Around a nerve or group of nerves.

perioperative  

Around the time of surgery; usually lasts from the time of going into the hospital or doctor's office for surgery until the time the patient goes home.

peripheral blood  

Blood circulating throughout the body.

peripheral blood lymphocyte therapy  

A treatment for Epstein-Barr virus infection or overgrowth of white blood cells (lymphocytes) after an organ or bone marrow transplant. Specific lymphocytes from a sibling donor are infused into the patient to try and reverse these conditions.

peripheral neuropathy  

A condition of the nervous system that causes numbness, tingling, burning or weakness. It usually begins in the hands or feet, and can be caused by certain anticancer drugs.

peripheral stem cell support  (per-IF-er-al)

A method of replacing blood-forming cells destroyed by cancer treatment. Immature blood cells (stem cells) in the circulating blood that are similar to those in the bone marrow are removed from the blood before treatment and given back after treatment. Also called peripheral stem cell transplantation.

peripheral stem cell transplantation  (per-IF-er-al)

A method of replacing blood-forming cells destroyed by cancer treatment. Immature blood cells (stem cells) in the circulating blood that are similar to those in the bone marrow are given after treatment to help the bone marrow recover and continue producing healthy blood cells. Transplantation may be autologous (an individual's own blood cells saved earlier), allogeneic (blood cells donated by someone else), or syngeneic (blood cells donated by an identical twin). Also called peripheral stem cell support.

peripheral stem cells  

Immature cells found circulating in the bloodstream. New blood cells develop from peripheral stem cells.

peristalsis  (pair-ih-STAL-sis)

The rippling motion of muscles in the intestine or other tubular organs characterized by the alternate contraction and relaxation of the muscles that propel the contents onward.

peritoneal  

Having to do with the peritoneum (the tissue that lines the abdominal wall and covers most of the organs in the abdomen).

peritoneal cavity  

The space within the abdomen that contains the intestines, the stomach, and the liver. It is bound by thin membranes.

peritoneal perfusion  

A method of delivering fluids and drugs directly to tumors in the peritoneal cavity.

peritoneum  (PAIR-ih-toe-NEE-um)

The tissue that lines the abdominal wall and covers most of the organs in the abdomen.

pernicious anemia  (per-NISH-us a-NEE-mee-a)

A type of anemia (low red blood cell count) caused by the body's inability to absorb vitamin B12.

PET scan  

Positron emission tomography scan. A computerized image of the metabolic activity of body tissues used to determine the presence of disease.

petechiae  (peh-TEH-kee-a)

Pinpoint, unraised, round red spots under the skin caused by bleeding.

phagocyte  

An immune system cell that can surround and kill microorganisms and remove dead cells. Phagocytes include macrophages.

phantom limb pain  

The sensation of pain or other unpleasant feelings in the place of a missing (phantom) limb.

pharmacokinetics  

The activity of drugs in the body over a period of time, including the processes by which drugs are absorbed, distributed in the body, localized in the tissues, and excreted.

pharynx  (FAIR-inks)

The hollow tube about 5 inches long that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach).

phase I trial  

The first step in testing a new treatment in humans. These studies test the best way to give a new treatment (for example, by mouth, intravenous infusion, or injection) and the best dose. The dose is usually increased a little at a time in order to find the highest dose that does not cause harmful side effects. Because little is known about the possible risks and benefits of the treatments being tested, phase I trials usually include only a small number of patients who have not been helped by other treatments.

phase I/II trial  

A trial to study the safety, dosage levels, and response to a new treatment.

phase II trial  

A study to test whether a new treatment has an anticancer effect (for example, whether it shrinks a tumor or improves blood test results) and whether it works against a certain type of cancer.

phase II/III trial  

A trial to study response to a new treatment and the effectiveness of the treatment compared with the standard treatment regimen.

phase III trial  

A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people.

phase IV trial  

After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase III trial. Thousands of people are involved in a phase IV trial.

phenethyl isothiocyanate  

PEITC. A naturally occurring compound found in some cruciferous vegetables. It is being studied as an agent to prevent cancer.

phenobarbital  

A sedative/anticonvulsant barbiturate that has been used to treat diarrhea and to increase the antitumor effect of other therapies.

phenoxodiol  

A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called signal transduction inhibitors.

phenylacetate  

A drug being studied in the treatment of cancer.

phenylbutyrate  

An anticancer drug that belongs to the family of drugs called differentiating agents.

pheresis  (fer-E-sis)

A procedure in which blood is collected, part of the blood such as platelets or white blood cells is taken out, and the rest of the blood is returned to the donor. Also called apheresis.

Philadelphia chromosome  

An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it. Bone marrow cells that contain the Philadelphia chromosome are often found in chronic myelogenous leukemia.

phosphorous  (FOS-for-us)

Having to do with or containing the element phosphorus.

phosphorus  (FOS-for-us)

A nonmetallic element that is found in the blood, muscles, nerves, bones, and teeth and is a component of adenosine triphosphate (ATP; the primary energy source for the body's cells).

phosphorus-32  

A radioactive form of phosphorus used in the treatment of cancer. It is also used to help locate areas of DNA damage.

photodynamic therapy  (fo-toe-dye-NAM-ik)

Treatment with drugs that become active when exposed to light. These drugs kill cancer cells.

photofrin  

A drug used in photodynamic therapy that is absorbed by tumor cells. When absorbed by cancer cells and exposed to light, photofrin becomes active and kills the cancer cells.

photosensitizer  

A drug used in photodynamic therapy. When absorbed by cancer cells and exposed to light, the drug becomes active and kills the cancer cells.

phyllodes tumor  

A type of tumor found in breast tissue. It is often large and bulky and grows quickly. It is usually benign (not cancer), but may be malignant (cancer). Also called cystosarcoma phyllodes.

physical therapist  

A health professional who teaches exercises and physical activities that help condition muscles and restore strength and movement.

physical therapy  

The use of exercises and physical activities to help condition muscles and restore strength and movement. For example, physical therapy can be used to restore arm and shoulder movement and build back strength after breast cancer surgery.

Physician Data Query  

PDQ. The Physician Data Query is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information is available on the Cancer.gov Web site. More specific information about PDQ can be found at http://cancer.gov/cancer_information/pdq/.

physiologic  

Having to do with the functions of the body. When used in the phrase "physiologic age," it refers to an age assigned by general health, as opposed to calendar age.

phytic acid  

A substance that has been studied as a treatment for cancer. Phytic acid is found in large amounts in cereals and legumes. Also known as inositol hexaphosphate.

phytochemicals  

Chemicals found in plants. Many of these chemicals are thought to reduce a person's risk of getting cancer.

phytosterols  

Plant-based compounds that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels. Phytosterols may have some effect in cancer prevention. Also called plant sterols.

pigment  

A substance that gives color to tissue. Pigments are responsible for the color of skin, eyes, and hair.

pilocarpine  

A drug used to increase salivation in people who have dry mouth caused by opioids or radiation therapy. Pilocarpine belongs to the family of drugs called alkaloids.

pilocytic  (PI-lo-SIT-ik)

Made up of cells that look like fibers when viewed under a microscope.

pilot study  

The initial study examining a new method or treatment.

pineal body  

A tiny organ located in the cerebrum that produces melatonin. Also called pineal gland or pineal organ.

pineal gland  (PIN-ee-al)

A tiny organ located in the cerebrum that produces melatonin. Also called pineal body or pineal organ.

pineal organ  

A tiny organ located in the cerebrum that produces melatonin. Also called pineal body or pineal gland.

pineal region tumors  (pIN-ee-al...TOO-mers)

Types of brain tumors that occur in or around the pineal gland, a tiny organ near the center of the brain.

pineoblastoma  (PIN-ee-o-blas-TOE-ma)

A fast growing type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

pineocytoma  (PIN-ee-o-sye-TOE-ma)

A slow growing type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

piperacillin-tazobactam  

A combination of drugs used to fight infections in people who have cancer. Piperacillin is a synthetic penicillin; tazobactam enhances the effectiveness of piperacillin.

pirfenidone  

A substance that is being studied in the prevention and treatment of scar tissue caused by radiation therapy. It belongs to the family of drugs called anti-inflammatory agents.

piritrexim  

An anticancer drug.

pituitary gland  (pih-TOO-ih-tair-ee)

The main endocrine gland. It produces hormones that control other glands and many body functions, especially growth.

placebo  

An inactive substance that looks the same as, and is administered in the same way as, a drug in a clinical trial.

placenta  

The organ that nourishes the developing fetus in the uterus.

placental blood transplantation  

The transfer of blood from a placenta to an individual whose own blood production system is suppressed. Placental blood contains high levels of stem cells needed to produce new blood cells. It is being studied in the treatment of cancer and severe blood disorders such as aplastic anemia. Also called umbilical cord blood transplant.

plant sterols  

Plant-based compounds that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels. Plant sterols may have some effect in cancer prevention. Also called phytosterols.

plasma  (PLAS-ma)

The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

plasma cells  

A type of white blood cell that produces antibodies.

plasma membrane  

The outer membrane of a cell.

plasmacytoma  (PLAS-ma-sye-TOE-ma)

Cancer of the plasma cells (white blood cells that produce antibodies) that may turn into multiple myeloma.

plasmapheresis  (plas-ma-fer-EE-sis)

The process of separating certain cells from the plasma in the blood by a machine; only the cells are returned to the person. Plasmapheresis can be used to remove excess antibodies from the blood.

plastic surgeon  

A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.

platelets  (PLAYT-lets)

A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called thrombocytes.

platinum  

A metal that is an important component of some anticancer drugs, such as cisplatin and carboplatin.

pleomorphic  

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

pleura  (PLOOR-a)

A thin layer of tissue covering the lungs and the wall of the chest cavity to protect and cushion the lungs. A small amount of fluid that acts as a lubricant allows the lungs to move smoothly in the chest cavity during breathing.

pleural cavity  

A space enclosed by the pleura (thin tissue covering the lungs and lining the interior wall of the chest cavity). The pleural cavity is bound by thin membranes.

pleural effusion  

An abnormal collection of fluid between the thin layers of tissue (pleura) lining the lung and the wall of the chest cavity.

pleurodesis  (PLOO-ro-DEE-sis)

A surgical procedure that causes the membranes around the lung to stick together and prevents the buildup of fluid in the space between the membranes.

plexopathy  (pleks-AH-pah-thee)

A disorder affecting a network of nerves, blood vessels, or lymph vessels.

ploidy  (PLOY-dee)

The number of sets of chromosomes in a cell or an organism. For example, haploid means one set and diploid means two sets.

pM-81 monoclonal antibody  

A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

pneumatic larynx  (noo-MAT-ik LAIR-inks)

A device that uses air to produce sound to help a laryngectomee talk.

pneumonectomy  (noo-mo-NEK-toe-mee)

An operation to remove an entire lung.

pneumonia  (noo-MONE-ya)

An inflammatory infection that occurs in the lung.

PNU 166148  

A drug that belongs to the family of drugs called topoisomerase inhibitors. It is being studied for its ability to treat cancer.

PNU-93914  

A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called topoisomerase inhibitors.

polyneuritis  

Inflammation of several peripheral nerves at the same time.

polyp  (POL-ip)

A growth that protrudes from a mucous membrane.

polyposis  

The development of numerous polyps (growths that protrude from a mucous membrane).

polysaccharide  

A type of carbohydrate. It contains sugar molecules that are linked together chemically.

pons  

Part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain. It is part of the brainstem.

pontine  

Having to do with the pons (part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain).

porfimer sodium  

An anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called photosensitizing agents.

porfiromycin  

An anticancer drug that belongs to the family of drugs called anticancer antibiotics.

port  

An implanted device through which blood may be withdrawn and drugs may be infused without repeated needle sticks. Also called a port-a-cath.

port-a-cath  

An implanted device through which blood may be withdrawn and drugs may be infused without repeated needle sticks. Also called a port.

positive axillary lymph nodes  

Lymph nodes in the area of the armpit (axilla) to which cancer has spread. This spread is determined by surgically removing some of the lymph nodes and examining them under a microscope to see whether cancer cells are present.

positive test result  

A test result that reveals the presence of a specific disease or condition for which the test is being done.

positron emission tomography scan  

PET scan. A computerized image of the metabolic activity of body tissues used to determine the presence of disease.

postmenopausal  

Refers to the time after menopause. Menopause is the time in a woman's life when menstrual periods stop permanently; also called "change of life."

postoperative  

After surgery.

postremission therapy  

Anticancer drugs given to kill cancer cells that survive after remission induction therapy.

potassium  (po-TASS-ee-um)

A metallic element that is important in body functions such as regulation of blood pressure and of water content in cells, transmission of nerve impulses, digestion, muscle contraction, and heartbeat.

potassium hydroxide  

A toxic and highly corrosive chemical used to make soap, in bleaching, and as a paint remover. It is used in small amounts as a food additive and in the preparation of some drugs.

PR+  

Progesterone receptor positive. Breast cancer cells that have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR+ need the hormone progesterone to grow and will usually respond to hormonal therapy.

PR-  

Progesterone receptor negative. Breast cancer cells that do not have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR- do not need the hormone progesterone to grow and usually do not respond to hormonal therapy.

precancerous  (pre-KAN-ser-us)

A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

precancerous dermatitis  

A skin disease marked by scaly or thickened patches on the skin, and often caused by prolonged exposure to arsenic. The patches often occur on sunexposed areas of the skin and in older white men. These patches may become malignant (cancerous). Also called Bowen's disease or precancerous dermatosis.

precancerous dermatosis  

A skin disease marked by scaly or thickened patches on the skin, and often caused by prolonged exposure to arsenic. The patches often occur on sunexposed areas of the skin and in older white men. These patches may become malignant (cancerous). Also called Bowen's disease or precancerous dermatitis.

precancerous polyps  

Growths that protrude from a mucous membrane. Precancerous polyps may (or are likely to) become cancer.

preclinical study  

Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.

predictive factor  (pre-DIK-tiv)

A situation or condition that may increase a person's risk of developing a certain disease or disorder.

prednisolone  

A synthetic corticosteroid used in the treatment of blood cell cancers (leukemias) and lymph system cancers (lymphomas).

prednisone  

Belongs to the family of drugs called steroids and is used to treat several types of cancer and other disorders. Prednisone also inhibits the body's immune response.

preleukemia  (PREE-loo-KEE-mee-a)

A disease in which the bone marrow does not function normally. Also called myelodysplastic syndrome or smoldering leukemia.

premalignant  

A term used to describe a condition that may (or is likely to) become cancer. Also called precancerous.

premenopausal  

Refers to the time before menopause. Menopause is the time of life when a women's menstrual periods stop permanently; also called "change of life."

prescription  

A doctor's order for medicine or another intervention.

pretracheal space  

The area in front of the trachea (windpipe).

preventive  

Used to prevent disease.

preventive mastectomy  

Surgery to remove one or both breasts in order to decrease the risk of developing breast cancer. Also called prophylactic mastectomy.

primary care doctor  

A doctor who manages a person's health care over time. A primary care doctor is able to give a wide range of care, including prevention and treatment, can discuss cancer treatment choices, and can refer a patient to a specialist.

primary central nervous system lymphoma  

Cancer that arises in the lymphoid tissue found in the central nervous system (CNS). The CNS includes the brain and spinal cord.

primary endpoint  

The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group). What the primary endpoint will be is decided before the study begins.  

primary tumor    

The original tumor.  

primitive neuroectodermal tumors (NOO-ro-ek-toe-DER-mul)

PNET. A type of bone cancer that usually forms in the middle (shaft) of large bones. Also called Ewing's sarcoma/primitive neuroectodermal tumor.

prinomastat  

An anticancer drug that belongs to the family of drugs called angiogenesis inhibitors. Prinomastat is a matrix metalloproteinase inhibitor. Also called AG3340.

procarbazine  

An anticancer drug that belongs to the family of drugs called alkylating agents.

prochlorperazine  (pro-klor-PAIR-a-zeen)

A drug that prevents or reduces nausea and vomiting. It belongs to the family of drugs called antiemetics.

proctoscopy  (prok-TOS -ko-pee)

An examination of the rectum using a thin, lighted tube called a proctoscope.

proctosigmoidoscopy  (PROK-toe-sig-moid-OSS-ko-pee)

An examination of the rectum and the lower part of the colon using a thin, lighted tube called a sigmoidoscope.

progeny  

Offspring; the product of reproduction or replication.

progesterone  (pro-JES-ter-own)

A female hormone.

progesterone receptor negative  (PR-)

PR-. Breast cancer cells that do not have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR- do not need the hormone progesterone to grow and usually do not respond to hormonal therapy.

progesterone receptor positive  (PR+)

PR+. Breast cancer cells that have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR+ need the hormone progesterone to grow and will usually respond to hormonal therapy.

progesterone receptor test  

A lab test to determine if breast cancer cells have progesterone receptors. If the cells have progesterone receptors, they may depend on progesterone for growth. This information can influence how the breast cancer is treated.

prognosis  (prog-NO-sis)

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

prognostic factor   (prog-NOS-tik)

A situation or condition, or a characteristic of a patient, that can be used to estimate the chance of recovery from a disease or the chance of the disease recurring (coming back).

progression  

Increase in the size of a tumor or spread of cancer in the body.

progression-free survival  

One type of measurement that can be used in a clinical study or trial to help determine whether a new treatment is effective. It refers to the probability that a patient will remain alive, without the disease getting worse.

progressive disease  

Cancer that is increasing in scope or severity.

proliferating  

Multiplying or increasing in number. In biology, cell proliferation occurs by a process known as cell division.

proliferative index  

A measure of the number of cells in a tumor that are dividing (proliferating). May be used with the S-phase fraction to give a more complete understanding of how fast a tumor is growing.

prolymphocytic leukemia  

A rare, aggressive type of chronic lymphocytic leukemia in which too many immature white blood cells are found in the blood, spleen, and bone marrow.

promegapoietin  

A colony-stimulating factor that stimulates the production of blood cells, especially platelets; it is given during chemotherapy to increase blood cell regeneration. Promegapoietin is a cytokine that belongs to the family of drugs called hematopoietic (blood-forming) agents.

promyelocytic leukemia  

A type of acute myeloid leukemia, a quickly progressing disease in which too many immature blood-forming cells are found in the blood and bone marrow.

prophylactic cranial irradiation  (pro-fih-LAK-tik KRAY-nee-ul ir-ray-dee-AY-shun)

Radiation therapy to the head to reduce the risk that cancer will spread to the brain.

prophylactic mastectomy   (pro-fi-LAK-tik mas-TEK-toe-mee)

Surgery to remove one or both breasts in order to decrease the risk of developing breast cancer. Also called preventive mastectomy.

prophylactic oophorectomy  (pro-fi-LAK-tik o-o-for-EK-toe-mee)

Surgery intended to reduce the risk of ovarian cancer by removing the ovaries before disease develops.

prophylactic surgery  

Surgery to remove an organ or gland that shows no signs of cancer, in an attempt to prevent development of cancer of that organ or gland. Prophylactic surgery is sometimes chosen by people who know they are at high risk for developing cancer.

prophylaxis  

An attempt to prevent disease.

prospective  

In medicine, a study or clinical trial in which participants are identified and then followed forward in time.

Prost 30 monoclonal antibody  

A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

prostate  (PROS-tate)

A gland in the male reproductive system just below the bladder. The prostate surrounds part of the urethra, the canal that empties the bladder, and produces a fluid that forms part of semen.

prostate-specific antigen  

PSA. A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.

prostatectomy  (pros-ta-TEK-toe-mee)  

An operation to remove part or all of the prostate. Radical (or total) prostatectomy is the removal of the entire prostate and some of the tissue around it.

prostatic acid phosphatase  (FOS-fa-tays)

PAP. An enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer.

prostatic intraepithelial neoplasia  (pros-TAT-ik in-tra-eh-pih-THEEL-ee-ul NEE-o-play-zha)

PIN. Noncancerous growth of the cells lining the internal and external surfaces of the prostate gland. It is an important sign that prostate cancer may develop.

prosthesis  (pros-THEE-sis)

An artificial replacement of a part of the body.

prosthodontist  (pros-tho-DON-tist)

A dentist with special training in making replacements for missing teeth or other structures of the oral cavity to restore an individual's appearance, comfort, or health.

protease inhibitors  

Compounds that interfere with the ability of certain enzymes to break down proteins. Some protease inhibitors can keep a virus from making copies of itself (e.g., AIDS virus protease inhibitors), and some can prevent cancer cells from spreading.

protein  (PRO-teen)

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

proteoglycan  

A molecule that contains both protein and glycosaminoglycans, which are a type of polysaccharide. Proteoglycans are found in cartilage and other connective tissues.

protocol  

An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered.

proton  

A small, positively charged particle of matter found in the atoms of all elements. Streams of protons generated by special equipment can be used for radiation treatment.

proton magnetic resonance spectroscopic imaging  

A noninvasive imaging method of detecting and measuring activity at the cellular level. It provides chemical information and is used in conjunction with magnetic resonance imaging (MRI), which gives spatial information. Also called 1H-nuclear magnetic resonance spectroscopic imaging.

protozoal  

Having to do with the simplest organisms in the animal kingdom. Protozoa are single-cell organisms, such as ameba, and are different from bacteria, which are not members of the animal kingdom. Some protozoa can be seen without a microscope.

PS-341  

A drug that belongs to the family of drugs called dipeptidyl boronic acids. It is being studied for its ability to treat cancer.

PSA  

Prostate-specific antigen. A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.

psammoma bodies  (sam-O-ma)

Structures found in some benign (noncancerous) or malignant (cancerous) tumor cells that look like hardened concentric rings when viewed under a microscope. Can be a sign of chronic inflammation.

PSC 833  

A drug that belongs to the family of drugs called cyclosporine analogues. It is used with chemotherapy to prevent or overcome the resistance of tumor cells to some anticancer drugs.

pseudomyxoma peritonei  (SOO-doe-mix-O-ma PAIR-ih-TOE-nee-I)

A build-up of mucus in the peritoneal cavity. The mucus may come from ruptured ovarian cysts, the appendix, or from other abdominal tissues, and mucus-secreting cells may attach to the peritoneal lining and continue to secrete mucus.

psoralen  

A substance that binds to the DNA in cells and stops them from multiplying. It is being studied in the treatment of graft-versus-host disease and is used in the treatment of psoriasis and vitiligo.

psoriasis  

A chronic disease of the skin marked by red patches covered with white scales.

psychologist  

A specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.

PTC  

Percutaneous transhepatic cholangiography (per-kyoo-TAN-ee-us trans-heh-PAT-ik ko-LAN-jee-AH-gra-fee). A procedure to x-ray the hepatic and common bile ducts. A contrasting agent is injected into the liver or bile duct, and the ducts are then x-rayed to find the point of obstruction.

PTK787/ZK 222584  

An anticancer drug that belongs to the family of drugs called angiogenesis inhibitors.

pulmonary  

Relating to the lungs.

pulmonary sulcus tumor  

Non-small cell lung cancer that originates in the upper portion of the lung and extends to other nearby tissues such as the ribs and vertebrae. Also called a Pancoast tumor.

pump  

A device that is used to deliver a precise amount of drug at a specific rate.

pyrazine diazohydroxide  

An anticancer drug.

pyrazoloacridine  

An anticancer drug that belongs to the family of drugs called acridines.