AIMatMelanoma.org
en gb fr de es it iw el nl da fi sv no pl ru cs

Glossary


P

  • Paclitaxel - A chemotherapeutic agent that is approved for treatment of some cancers and currently under investigation for treatment of metastatic melanoma. It belongs to a class of drugs called taxanes; also known as Taxol.
  • Palliative Care - Relieves symptoms and improves a patient’s quality of life, but does not treat the disease.
  • Palpate - To examine by pressing on the surface of the body to feel the organs or tissues underneath.
  • Papillary Dermis - The upper part of dermis (the deeper part of the skin), made up of loose connective tissue.
  • Pathologist - A doctor who specializes in identifying diseases by studying cells and tissues under a microscope.
  • Pathology - The study of diseased tissue.
  • PDQ Information Systems - Physician Data Query. PDQ is an online database developed and maintained by the National Cancer Institute. It is designed to make the most current, credible, and accurate cancer information available to health professionals and the public.
  • Pegylated (PEG) Interferon - A new form of long-acting interferon that has been FDA approved for treatment of viral hepatitis and is being investigated for the treatment of advanced high-risk melanoma.
  • Peptide Vaccine - A vaccine in which antigens are produced from synthetic peptides and transported through the bloodstream by an adjuvant in order to stimulate an immune response.
  • Peptides - Combinations of amino acids. Peptides combine to make proteins, including antigens.
  • Perfusion - A chemotherapy technique that may be used when melanoma occurs on an arm or leg. The flow of blood to and from the limb is stopped for a while with a tourniquet, and anticancer drugs are put directly into the blood of the limb. This allows the patient to receive a high dose of drugs in the area where the melanoma occurred.
  • PET Scan - A diagnostic test that produces images of the body by detecting radiation emitted from a radioactive substance that is administered to the patient.
  • Phase 1 Trial - Clinical trial conducted to find the safest dose and most-effective way to give a new cancer treatment to patients, as well as to identify potential side effects. Phase 1 trials are usually limited to a small number of patients who would not be helped by other known treatments.
  • Phase 2 Trial - Clinical trial conducted to test how well a new cancer treatment works against a certain type of cancer.
  • Phase 3 Trial - Clinical trial conducted to compare the new cancer treatment with the standard treatment to discover which treatment is more effective. Phase 3 trials involve large numbers of patients who are assigned at random to receive either the new treatment or the standard treatment. In most cases, studies move into phase 3 only after a treatment seems to work in phases 1 and 2.
  • Pheomelanin - A red-yellow form of pigment characteristically found in fair-skinned, red-headed people.
  • Photosensitivity - Sensitivity to the sun and the effects of ultraviolet radiation.
  • Pigment - A substance that gives color to tissue. Pigments are responsible for the color of skin, eyes, and hair.
  • Pigmented Lesion - A skin spot that has color.
  • Placebo - A substance that looks the same as, and is administered in the same way as, a drug in a clinical trial, but does not contain any active ingredients.
  • Plasma - The liquid part of the blood which contains salts minerals and protein and is yellow in color.
  • Plasma Cells - Large immune cells that produce millions of antibodies identical to those on the parent B-cell that stimulates their production.
  • Platelets - Small pieces of cells that are found in the blood and are specially designed to form blood clots when correctly stimulated. They are also known as thrombocytes.
  • Positive - Describing a tissue sample in which cancer cells are found.
  • Positron Emission Tomography (PET) Scan - A procedure in which radioactive sugar molecules, called tracers, are injected into the body in a low-dose, radioactive form. During the scan, the cancer cells "light up," because the cancer cells absorb sugar faster than normal cells.
  • Prevalence - Percentage of a population that is affected by a particular disease at a given time.
  • Primary Site - The part of the body in which a cancer first appears.
  • Primary Tumor (Lesion) - The original tumor.
  • Procarbazine - A chemotherapeutic agent sometimes used in the treatment of pediatric cancers including melanoma.
  • Prognosis - A prediction of the probable course of the disease.
  • Protein - A complex molecule that is a basic constituent of all living cells.
  • Punch Biopsy - A type of incisional biopsy in which the doctor removes a portion of a suspicious lesion by rotating a small cookie-cutter-like tool down through the full thickness of the skin to the underlying fat.