Otolaryngology: Open Access
Open Access

Abstract

Radiation damage to the head and neck after radiotherapy is known to be associated with high T stage, the type of surgical intervention, the use of, the dose and the site of radiotherapy. There may be a reduction in damage using intensity modulated radiotherapy with but damage can be increased by concurrent use of chemotherapy. Radiation damage to muscles and many other tissues occurs by a process of fibrosis. This restricts the action of the muscles and in the heads and neck is exhibited in a number of ways. Consequently a high proportion of patients receiving radiotherapy for head and neck cancer report some degree of dysphagia and trismus. Between 32 to 83% of patients receiving radiotherapy for head and neck cancer report some degree of dysphagia. Between 3-90% of post radiotherapy patients suffer from trismus. Depending on the severity, the limited mouth opening and loss of masticatory function can cause difficulties with daily activities such as eating, chewing, swallowing, breathing, and speaking. It can lead to further problems such as severe pain, weight loss, and poor oral hygiene. The resultant limited access to the oral cavity can also make it impossible to clinically diagnose recurrence at this site. In terms of radiotherapy damage to the head and neck perhaps the most obvious but least common is osteoradionecrosis of the jaws and other bones. It is now well recognized that osteoradionecrosis is a consequence of fibrotic change in bone. The reported incidence of this varies but has been put at between 2-22%. The severity of this condition and its consequent effect on the patient is extremely variable, with a spectrum ranging from entirely asymptomatic to causing severe pain, disfigurement and functional impairment of the jaws. All these fibrotic conditions can result in anxiety and depression and a significant impairment in quality of life. There are a number of genotypes may be indicative of susceptibility to fibrotic radiation damage, potentially giving a method of prediction to how the normal tissues individuals will respond to radiotherapy. This certainly includes a polymorphism in the transforming factor beta promoter gene, which has been shown to be predictive of osteoradionecrosis and trismus. Genome wide association studies may be used in the future and this constitutes an ongoing research project, to enable identification of other genotypes. The aim is to be able to identify those patients who are most at risk of radiation damage, and modify treatment accordingly.

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