Oral Mucositis, Incidence, Risk factors, Clinical Features, Scoring, Pathophysiology and Treatment: A Review of Literature

Cancer is a broad group of different diseases involve the unregulated cell growth in which the cells divide uncontrollably forming the malignant tumors. The management are by chemotherapy, surgery, radiation therapy or by other treatments. Oral mucositis refers to the inflammation and ulceration that occurs in the mouth and considered as a side effect of chemotherapy and/or radiotherapy treatment for malignant tumor. The aim of this study was to review the incidence, risk factors, clinical features, scoring, pathophysiology and treatment of oral mucositis. The incidence of oral mucositis is varying from patient to patient depending on the type, dose and duration of the treatment the patient receives. The risk factors are the patient-related factors (like the age, gender, racial factor, poor oral hygiene, periodontal disease, nutritional status, xerostomia, co-existing diseases, tobacco use and alcohol consumption) and the treatment-related risk factors which includes the chemotherapy risk factors (like the type of chemotherapy, dose and duration) and the radiation therapy risk factors (like the anatomical area irradiated, volume of tissue irradiated, total dose, fractionation regimen) and the concomitant chemotherapy. Oral mucositis clinically starts with redness and then progresses to the development of large and very painful pseudomembranous lesions associated with dysphagia. The non-keratinized mucosa is mostly affected than the keratinized mucosa. The pain can be so debilitating to the oral activities like swallowing, mastication, drinking and speech. Both oral and gastro intestinal mucositis may be associated with infection-related deaths and can be a dose-limiting factor for chemotherapy which affect the patient survival. A variety of scales have been used to record the severity of oral mucositis like the WHO scale and the scoring systems by national cancer institute. The WHO scale is the most widely used and includes criteria which are the presence of erythema and ulceration oral pain and the patient’s inability to eat. Regarding the pathophysiology, five phases have been identified in the development of oral mucositis and mucosal restoration. In the initiation phase tissue injury occurs following the administration of radiation or chemotherapy in which the DNA strand breakdown occur. This is followed by the primary damage response which result in the activation of several transduction pathways that activate transcription factors such as p53 and nuclear factor-κB. Signal amplification by pro-inflammatory cytokines like TNF-α can intensify the response to primary damage. The signals are amplified due to apoptosis, tissue damage and vascular permeability. This result in painful ulceration and superficial bacterial colonization. Then healing occur once the cancer therapy ends. There are only a few established treatments for oral mucositis like the topically applied cryotherapy, laser therapy, antibiotic lozenges, benzydamine hydrochloride, chlorhexidine and some herb extract mouth washes. A systemic administration of indomethacin, amifostine, growth factors or palifermin can cause a significant reduction in the severity of oral mucositis. Keywords Oral mucositis; Chemotherapy; Radiation therapy; Oral ulcerations