Guidelines for Complications of Cancer Treatment Vol VIII Part B

The incidence of mucositis involving oral cavity andgastrointestinal mucosa varies between 5-15% with standarddose chemotherapy whereas it can be as high as 80-100% withhigh dose chemotherapy and stem cell transplantation.However, considering the risk of mucositis with each cycle ofchemotherapy in solid tumors, the overall burden is higher inthis subgroup than in hematological malignancies. The reportedincidence of diarrhea varies from 1-3% with mostchemotherapy regimens however combinations such asirinotecan and oxaliplatin can increase the risk to 16-25%.Alimentary mucositis (AM) is the term which isrecommended by the mucositis study group of MultinationalAssociation of Supportive Care in Cancer and the InternationalSociety for Oral Oncology to describe cancer therapyassociated mucosal injury of the alimentary tract (mouth toanus). This unifying term acknowledges the similarities alongthe entire GI tract while allowing for regional differences thatrequire discussion of oral and GI mucositis separately at timesbased on pathophysiologic responses and clinicalcharacteristics.Pathogenesis- Mucosal injury is the first step in thedevelopment of mucositis. It results in changes in mucosa,submucosa and connective tissue matrix mediated by a numberof pro-inflammatory cytokines, reactive oxygen species,ceramide pathway and a number of other transcription factorincluding NF-kb. The resultant degradation of connectivetissue matrix and upregulation of number of other genes leadto apoptosis of clonogenic stem cells in basal layer ofepithelium. This coupled with reduced proliferative capacityof surrounding epithelium leads to ulceration of mucosa. Theulcerative phase is further compounded by the bacterialcolonization and the resultant cytokine release due to bacterialcell wall components. Ultimately healing occurs by themigration of healthy epithelium from wound margins. The455