Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract (GI tract) and accessory organs of digestion, including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The symptoms relate to the organ affected and can include obstruction (leading to difficulty swallowing or defecating), abnormal bleeding or other associated problems. The diagnosis often requires endoscopy, followed by biopsy of suspicious tissue. The treatment depends on the location of the tumor, as well as the type of cancer cell and whether it has invaded other tissues or spread elsewhere. These factors also determine the prognosis.
Overall, the GI tract and the accessory organs of digestion (pancreas, liver, gall bladder) are responsible for more cancers and more deaths from cancer than any other system in the body. There is significant geographic variation in the rates of different gastrointestinal cancers.
Stomach cancer, or gastric cancer, refers to cancer arising from any part of the stomach. Stomach cancer causes about 800,000 deaths worldwide per year. Prognosis is poor (5-year survival <5 to 15%) because most patients present with advanced disease.
Digestive system surgery can be divided into upper GI surgery and lower GI surgery.
Upper gastrointestinal surgery, often referred to as upper GI surgery, refers to a practise of surgery that focuses on the upper parts of the gastrointestinal tract. There are many operations relevant to the upper gastrointestinal tract that are best done only by those who keep constant practise, owing to their complexity. Consequently, a general surgeon may specialise in 'upper GI' by attempting to maintain currency in those skills.
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.