It is the area it originally arose from which determines what type of cancer it is. In practice, the most common types of cancer to arise in the oropharynx are from the tonsils and tongue base , and most research has been done on therapy for these areas. Cells in the throat are subjected to lots of injury from heat and abrasion, and thus must divide frequently to replace those lost due to injury and old age. Normally, cells divide quickly as we develop in the womb and through infancy, and then the rate slows down considerably, just to replace cells that die. The division of cels in the throat and elsewhere is under very tight control, regulated by the genes within the cells.
Cancer starts in a single, abnormal cell unable to control it's division processes.
Cancers of the throat tend to grow to large sizes locally before they spread, but any cancer can spread at any time. Each year in the United States there are about 8,000 new cases of oropharynx cancer leading to 3,000 deaths annually from this disease. Men are affected twice as often as women. There are about 150,000 new cancers of the entire head and neck area each year, which causes 20,000 deaths annually. The average patient is 60 years old.