Pathologic Model Divides Oral Mucositis Into Five Phases

The oral mucosa is made up of epithelial cells that regenerate every 7–14 days, making them easily damaged by chemotherapy and radiation therapy. When unable to regenerate, the oral mucosa becomes thinner and ulceration can occur, giving pathogens entry into the body. People with ulcerations in their oral mucosa are at significantly increased risk of infection, which can become severe and even life-threatening. A pathologic model of mucositis, divided into five phases, was developed by Sonis (2004, as cited in Brown, 2010). 

The process of mucosal damage begins soon after administration of chemotherapy and radiation therapy. While many patients do not experience any symptoms indicative of mucosal damage until the ulceration phase, damage to the mucosa occurs through a variety of biologic processes during the first three stages. Eventual healing of the oral mucosa does occur, but this can take some time and may be slowed by additional administrations of chemotherapy and radiation therapy.


Brown, C.G. (2010). Oral mucositis. In C.G. Brown (Ed.), A guide to oncology symptom management (pp. 333–345). Pittsburgh, PA: Oncology Nursing Society.