Glossary of Cancer Terms


Paget’s Disease of the Nipple

A form of breast cancer that occurs in the nipple. Symptoms commonly include itching, and an eczema-like condition around the nipple, almost never found on both breasts.

Pain threshold

The point at which a person becomes aware of pain.


The roof of the mouth. This structure separates the mouth and the nasal cavity. The front portion is bony (hard palate)., and the back portion is muscular (soft palate).

Palliative treatment

Treatment that aims to improve well-being, relieve symptoms or control the growth of cancer, but not primarily intended or expected to produce a cure.


Examination by feeling an area of the body, such as the breast or prostate, with the fingers to detect abnormalities. A palpable mass is one that can be felt.


An organ of the digestive system located deep in the abdomen behind the stomach close to the backbone. The pancreas produces both external and internal secretion. The external secretion, called pancreatic juice plays an important role in the digestion of food. The internal secretion includes the hormones insulin and glucagon, which along with other hormones in the body play an important role in the metabolism of carbohydrates.

Pancreatic Cancer A common malignancy that is treatable if diagnosed early but is rarely curable. Diagnosis is usually not possible until symptoms appear and by that time the cancer is often advanced. Ninety percent of pancreatic cancers are adenocarcinomas. These develop in the exocrine glands which produce enzymes that aid in digestion. There are other types of cancer that develop in the endocrine glands or islet cells. The endocrine glands produce homones such as insulin. Islet cell cancers are very uncommon. Unlike the more common exocrine pancreatic cancers, islet cell tumors are sometimes curable.

Pap test (Pap smear)

A study for early detection of cancer cells. It involves collecting material from areas of the body which shed cells or in which shed cells collect, especially the cervix and vagina. This material is then prepared for microscopic study by a special staining test. Analysis of the cells is helpful in diagnosing cancer.


Swelling around the optic nerve, usually due to pressure on the nerve by a tumor.


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

Parathyroid One of four small endocrine glands located on the back of, at the lower edge of, or embedded within the thyroid gland. They excrete a hormone parathyroid hormone which helps to regulate calcium and phosphorus metabolism.
Parathyroid Cancer A rare endocrine gland cancer. Benign (non-cancerous) tumors of the parathyroid or adenomas are much more common (99%) than malignant tumors.


A doctor skilled in the performance and interpretation of laboratory tests and in the examination of tissues to provide a diagnosis.

Pathology report

Diagnosis made by a pathologist based on microscopic evidence.

Patient-controlled analgesia (PCA)

A method in which the person with pain controls the amount of pain medicine that is taken. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump. The medication is dispensed into the body via a small tube which has been inserted under the skin, into a vein or into the spine.


Concerning treatment of children.

Pediatric Cancers Refers to a group of cancers which occur specifically or usually in children.


The lower part of the abdomen between the hip bones. Organs in a female’s pelvis include the uterus, vagina, ovaries, fallopian tubes, bladder, rectum.

Per os (PO)

Refers to medications given orally or by mouth.

Percutaneous transhepatic cholangiography (PTC)

A test sometimes used to help diagnose cancer of the pancreas. During this test, a thin needle is put into the liver. Dye is injected into the bile ducts in the liver so that blockages can be seen on x-rays.

Peripheral Neuropathy

A problem with the functioning of the nerves outside of the spinal cord. The symptoms of a neuropathy may include numbness, weakness, burning pain (especially at night), and loss of reflexes. The pain may be severe and disabling. Can be caused by a variety of reasons for example, side effect of certain medications, illnesses such as diabetes or kidney failure.

Peripheral stem cell transplantation

The process of taking stem cells (immature blood cells) directly from the blood stream instead of using bone marrow. Stem cells are more concentrated in the bone marrow but they can also be extracted from the blood stream. The stem cells in the circulating blood that are similar to those in the bone marrow are then given to the person after treatment to help the bone marrow recover and continue producing healthy blood cells. Transplantation may be autologous (the person’s blood cells saved from earlier), or allogeneic (blood cells donated by someone else). Peripheral stem cells may also be used to supplement a bone marrow transplant.


The progressive wavelike movement that occurs involuntarily in hollow tubes in the body, particularly the digestive tract. This causes the contents of the tube to be forced onward.


The tissue that lines the inside of the abdomen.

Pernicious Anemia

A disorder of the red blood cells caused by a lack of vitamin B12. Patients who have this disorder do not produce the substance in the stomach that allows the body to absorb vitamin B12. May be fatal if not treated with vitamin B12, iron and diet.

PET (Positron emission tomography) Scan A computerized image of the metabolic activity of body tissues used to determine the presence of disease.


Tiny areas of bleeding under the skin usually caused by a low platelet count.


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).

Physical therapist

A health professional trained in the use of treatments aimed at rehabilitation concerned with restoration of function and prevention of disability following disease, injury or loss of body part.

Pineal gland

A glandlike structure in the brain. It produces melatonin. This hormone is believed to control the biological rhythms of the body.

Pineal region tumors

Tumors occuring in the region of the pineal gland (the rear of the third ventricle in the brain) Pineal region tumors represent fewer than 1% of all primary brain tumors. They include germinomas, teratomas, and other germ cell tumors, astrocytomas, and pineal tumors.


A malignant form of a pineal gland tumor.


A slow-growing tumor located in the pineal gland.

Pituitary Adenoma A benign, slow growing tumor of the pituitary gland. They represent about 15% of all primary brain tumors. They occur at any age but are rare before puberty. Pituitary adenomas are classified as secreting or non-secreting. The majority are secreting tumors and are further classified by the hormone that is secreted.
Pituitary Cancer Is the rare malignant form of pituitary adenomas. It is diagnosed only when there are proven metastases. Symptoms are identical to those of the adenoma, and may secrete a variety of hormones.

Pituitary gland

Is an endocrine gland secreting a number of hormones which regulate many bodily processes including growth, reproduction, and various metabolic activities. Often referred to as the master gland of the body.


An inactive substance, used in a research study or clinical trial, that looks like the medication. It is used to eliminate the improvement that may result from the belief that a medication is being given, rather than the actual effect of a medication.


The liquid part of blood. Fluid in which the cellular elements of the blood are suspended.

Plasma cells

A type of white blood cell responsible for producing antibodies that take part in the immune response.

Plasmacytoma Is a collection of malignant "cancerous" plasma cells that form a mass. Plasmacytomas affect either bones or soft tissues where, depending on the site affected, the clinical cause is defined. Plasmacytoma could be part of multiple myeloma, if the criteria for the latter are satisfied. Or it could be a free standing true disease, solitary plasmacytoma. A solitary plasmacytoma of the soft tissue or the bone could be cured by local treatment (i.e. radiation therapy). Multiple plasmacytomas or plasmacytomas that are part of multiple myeloma are treated with systemic therapy.


The process of replacing or "washing" of a patient's plasma. Plasmapheresis can be used to remove excess antibodies from the blood of multiple myeloma patients. Also used to replace a patient's plasma by donor plasma or saline.

Plastic surgeon

A physician who specializes in surgery to restore, repair, or reconstruct body structures.


One of the three kinds of circulating blood cells. Platelets have an important role in the clotting of blood. The normal platelet count is about 150,000 to 300,000. Platelet transfusions are used in cancer patients to prevent or control bleeding when the number of platelets has significantly decreased.

Pneumatic larynx

A device that uses air to produce sound to help a person, who has had their larynx (voice box) removed, talk.

P.O.E.M.S. A syndrome exhibiting various symptoms, one of the features is abnormal monoclonal protein. Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein and Skin changes.


A tumor with a pedicle. Commonly found in vascular organs such as the nose, uterus, and rectum. Polyps bleed easily; if there is a possibility that they will become cancerous they are surgically removed.

Port (infusion)

A small disk with a soft center (about the size of a quarter) that is surgically placed just below the skin in the chest or abdomen. A tube coming out of the side is connected to a large vein. By passing a small needle through the skin into the disk, fluids, drugs or blood products can be delivered directly to the bloodstream without worrying about finding an adequate vein, making multiple venipunctures or causing leakage of the fluids into surrounding tissues.


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

Power of attorney for healthcare

Legal documents to specify the person who will make health care decisions if the individual is unable to make those decisions personally.


Abnormal cellular changes or conditions that tend to become malignant. Also called premalignant.


A written direction or order for dispensing and administering drugs signed by a physician, dentist or other practitioner licensed by law to prescribe such a drug.

Primary Cancer

The place where a cancer first starts to grow. Even if it spreads elsewhere, it is stillknown by the place of origin. For example, breast cancer that has spread to the bone is still breast cancer, not bone cancer.

Primary Peritoneal Cancer Cancers that develop in the peritoneum (lining of the abdomen). Usually treated as an ovarian cancer.

Primitive Neuroectodermal Tumors (PNET)

Very rare types of brain tumors. PNET is a name used for tumors which appear identical under the microscope to the medulloblastoma, but occur primarily in the cerebrum. They most frequently occur in very young children. The tumors contain undeveloped brain cells, are highly malignant, and tend to spread throughout the central nervous system.


A visual examination of the rectum and the lower part of the colon (sigmoid colon), using a lighted instrument called a sigmoidoscope.


A female hormone. It is responsible for changes in the uterine lining during the menstrual cycle.

Progesterone receptor test

Lab test of tumor tissue to determine if a breast cancer depends on progesterone for its growth.


Prediction of course and end of disease, and the estimate of chance of recovery.

Prophylactic mastectomy

Surgery to remove a breast that is not known to contain cancer. In high-risk individuals this may be done for the purpose of reducing their risk of developing breast cancer.

Prophylactic surgery

Surgery to remove tissue that is in danger of becoming cancerous, before cancer has the chance to develop.


An attempt to prevent disease.

Prostate Cancer Malignancy of the prostate gland. Cancer of the prostate is the most common form of cancer occuring in men over age 65. It arises from the glands of the prostate and is known as adenocarcinoma, which means cancer of the glands. Most of these cancers develop in the bottom portion of the prostate that lies closest to the rectum. This is why rectal examination is useful in detecting this type of cancer.

Prostate gland

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


An operation to remove part or all of the prostate. Radical (or total) prostatectomy is the removal of the entire prostate and the seminal vesicles. The prostate can be removed through an incision in the abdomen (retropubic or suprapubic approach). Or by an incision between the scrotum and anus (perineal approach).

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.


An artificial replacement of a body part, such as a leg, breast, or eye, that is missing because of disease or treatment.


A dentist with special training in making replacements for missing teeth or other structures of the oral cavity to restore the patient’s appearance, comfort, and/or health.


An action plan for a clinical trial. The plan states what will be done in the study and why. It outlines how many people will take part in the study, what types of patients may take part, what tests they will receive and how often, and the treatment plan.


One who is trained in methods of psychological analysis, therapy and research. Can talk with patients and families about emotional and personal matters and help with decision making processes.

Pseudomyxoma Peritonei A type of tumor that develops in the peritoneum that produces large amounts of mucous like fluid. Can be either a benign or malignant disease.


Back to Top