Gustatory Function Following Radiotherapy to the Head and Neck
Research type
Research Study
Full title
Gustatory Function Following Radiotherapy to the Head and Neck
IRAS ID
244587
Contact name
Chris Nutting
Contact email
Sponsor organisation
Clinical R&D Manager
Clinicaltrials.gov Identifier
To be confirmed, Clinical Trials.gov
Duration of Study in the UK
1 years, 7 months, 31 days
Research summary
This is study to assess the loss and recovery of taste following radiotherapy and chemo-radiotherapy for head and neck cancer. It will involved both a prospective and cross-sectional cohort to assess both acute and late toxicity.
By using detailed dosimetric data derived from the radiotherapy planning system, we will be able to calculate mean radiation doses to important structures including the oral tongue, oral cavity, parotid and submandibular salivary glands, and correlate them with both qualitative and quantitative data for gustatory function. Such data will be used to generate radiation dose-response curves for taste function.
Quantitive measures will be in the form of taste recognition threshold testing using validated taste strips as well as photographs of the irradiated tongue to allow fungiform papillae density measurements.
Qualitative measures will be in the form of a patient reported taste survey, quality of life questionnaire and clinician assessed toxicity grading.
Patients in the prospective cohort will be followed up for 12 months and assessed at baseline, end of treatment, 2 months, 6 months and 12 months post completion of treatment.
Patients in the cross-sectional cohort will be seen just once, 12 months following completion of radiotherapy.
Summary of Results:
In the cross-sectional cohort, across all tumour sites a third of patients complain of dysfunction with even higher rates seen in those receiving treatment to the tongue. The pattern of taste loss is consistent with previous research but also consistent with that of the normal population suggesting further research to understand how radiation might differentially affect individual taste receptor cells is required. Although a relationship was present, the consistency between subjective and objective measures was poor and gustatory research must continue to collect data using a combination of objective and patient reported end points to fully capture the prevalence of dysfunction. The presence of hyperosmia (heightened sense of smell) in the cross-sectional cohort was an interesting finding and serves as a reminder that ‘problems with’ or ‘changes in’ should not be presumed to represent a deficit in function. It is an interesting phenomenon and warrants further research. There was a clear relationship between dose to the anterior two thirds of the tongue and taste dysfunction using both objective and subjective measures. Although this study was unable to clearly determine a constraint to avoid taste loss, it is clear that doses to the gustatory field must be kept to a minimum and even then, this is unlikely to be sufficient to prevent taste dysfunction altogether. In addition, the implementation of a constraint to the anterior two thirds of the tongue may prove challenging in particular for cancers involving the oropharynx, oral cavity or those requiring level 1b lymph node irradiation.In the prospective cohort, taste dysfunction remained a highly ranked toxicity affecting over a third of patients 6m following completion of treatment. The prospective nature of this study allowed for a more thorough analysis of dysfunction across taste qualities (all were affected similarly) and the impact of dose (where a general relationship was observed, keeping dose at the anterior two thirds of the tongue below 20 Gy may reduce if not completely prevent dysfunction). Dose aside, in a cohort of this size, it was difficult to use other clinical characteristics to predict which patients may suffer from taste dysfunction, although concurrent chemotherapy and xerostomia may be associated. Subjective taste dysfunction itself appears to be linked to a tendency to lose more weight during and after treatment, confirming once again the tangible impact of this adverse effect, psychosocial considerations aside.
REC name
London - West London & GTAC Research Ethics Committee
REC reference
18/LO/1394
Date of REC Opinion
20 Aug 2018
REC opinion
Further Information Favourable Opinion