Oral mucosa is made up of epithelial cells that regenerate every 7-14 days, making them easily damaged by chemotherapy and radiation therapy. Unable to regenerate, the oral mucosa becomes thinner and ulceration can occur allowing pathogens entry into the body. People with ulcerations in their oral mucosa are at significantly increased risk of infections which can become severe and even life-threatening.
A pathologic model of mucositis was developed by Sonis. It is divided into 5 phases.
From “Oral Mucositis”, (p. 337) by Brown, C.G., in C.G.Brown (Ed.), A guide to oncology symptom management, 2010, Pittsburgh, PA: Oncology Nursing Society. Reprinted with permission.
Initiation of the process of mucosal damage begins soon after administration of chemotherapy and radiation therapy. Many patients do not experience any symptoms indicative of mucosal damage until the ulceration phase, but during the first three stages damage to the mucosa by a variety of biologic processes is occurring.
Eventual healing of the oral mucosa does occur, but can take some time and may be slowed by additional administrations of chemotherapy and radiation therapy.