Post-radiation Dental Disease Amongst Head and Neck Cancer Patients

Background Post-radiotherapy head and neck cancer (HANC) patients are at increased risk of dental caries and periodontal disease due to radiation-related damage to the teeth and salivary glands. Currently the exact aetiology of post-radiotherapy dental disease, and variation in its incidence and severity based on tumour location and radiotherapy dose, is poorly understood. Consequently there is a lack of clear guidance on how HANC patients should be dentally managed both before and after their radiotherapy. Aim The aim of this study is to quantify the relationship between dental radiation dose, 'spared' parotid gland radiation dose, tumour location, and post-radiotherapy dental disease. Methods A prospective cohort study will be undertaken in HANC patients treated with radiotherapy. A total of 215 patients will be recruited over a period of 2.5 years. Participants will be assessed and rendered dentally fit prior to radiotherapy in the School of Dentistry, Belfast. All patients will be followed-up at 6, 12, and 24-months post-radiotherapy. Data to be collected at each visit will include: total number of carious teeth, periodontal disease indices, salivary flow rates, diet, oral hygiene, mouth opening, xerostomia and oral health-related quality of life. Radiotherapy, including individual tissue-dose exposures, will be prescribed by the Clinical Oncology team as per current practice. Doses to the teeth and 'spared' parotid gland will be determined using radiotherapy research software (Non-Clinical Eclipse System sold by Varian Medical Systems UK Ltd). Using appropriate statistical tests, data analysis will determine the relationship between dental disease, radiation dose, and tumour location. Anticipated variation in the incidence and severity of post-radiotherapy dental disease based on the radiotherapy dose and tumour location, will inform the development of a clinical risk-assessment tool that will allow dentists to categorise patients as 'high' or 'low' risk of future disease. Guidelines regarding pre-radiotherapy dental extractions and post-radiotherapy preventative strategies will also be developed and will advise clinicians based on this risk assessment. A micro-costings study will be undertaken to evaluate patient and healthcare costs associated with the diagnosis and management of pre- and post-radiotherapy dental disease.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

\- Adult dentate patients diagnosed with a primary or secondary malignant tumour of the oral cavity, nasal cavity, sinuses, salivary glands, pharynx, or larynx\* requiring radiation treatment within Northern Ireland. \*International Classification of Diseases (ICD-10) codes C00.0-C14.8 and C30.0-32.9.

Exclusion Criteria:

* Patients deemed to have poor prognosis or to receive palliative treatment only (as advised by the Clinical Oncology team).
* Patients with less than 6 teeth before the radiotherapy start date.
* Patients with recurrent head and neck cancer, or patients receiving a repeat course of head and neck radiotherapy.
* Patients with diseases affecting tooth development (e.g. amelogenesis or dentinogenesis imperfecta) or salivary gland function (e.g. Sjogren's Syndrome).
* Patients with pre-existing trismus (mouth opening less than 35mm).