Waldenstrom's macroglobulinemia: A rare cancer of the lymph cells that causes the body to produce abnormal levels of plasma cells (plasmacytosis) and lymphocytes (lymphocytosis) in the bone marrow. Waldenstrom's macroglobulinemia may also cause a decrease in red blood cells (anemia) and enlargement of the liver (hepatomegaly), spleen (splenomegaly), or glands (adenopathy).

Warfarin: A drug that prevents blood from clotting. Also called an anticoagulant (blood thinner).

Wart: A raised growth on the surface of the skin or other organ.

Watchful waiting: Closely monitoring a patient's condition but withholding treatment until symptoms appear or change. Also called observation.

Whipple procedure: A type of surgery used to treat pancreatic cancer. The head of the pancreas, the duodenum, a portion of the stomach, and other nearby tissues are removed.

White blood cell: A type of cell in the immune system that helps the body fight infection and disease. White blood cells include lymphocytes, granulocytes, macrophages, and others.

Whitmore-Jewett staging system: A system used for the staging of prostate cancer.

Whole cell vaccine: Vaccine made from whole tumor cells that ha cells that have been changed in the laboratory.

Wilms' tumor: A kidney cancer that occurs in children usually younger than 5 years.

Wobe-Mugos E: A mixture made from an extract of the calf thymus gland and enzymes (proteins that sand enzymes (proteins that speed up chemical reactions in the body) from the papaya plant, the pancreas of cows, and pancreas of pigs. It has been used in Europe as a treatment for a variety of cancers and for Herpes virus infections.