Prospective Pilot Study Evaluating Dental Side Effects of Radiotherapy on Subjects Treated for Head and Neck Cancer

Prospective Pilot Study Evaluating Dental Side Effects of Radiotherapy on Subjects Treated for Head and Neck Cancer

Multi-centric, one arm phase II study. The first phase of the study will consist of an evaluation of the initial dental state of each subject based on a stomatological examination, an orthopantomogram, two bitewing radiographs (right and left sides) and an evaluation of all potential risks of caries and fractures. For all of subjects, a dental decalcification, dental care and/or avulsion if necessary, and afterwards, a dental splint will be performed before the start of RT treatment. Our previously developed predictive model for dental dose in function of the localisation of tumour and suspect lymph nodes based on the stomatological examination and on the pre-treatment imaging. An estimation of the intensity-modulated radiotherapy (IMRT) teeth dose will be made and translated into a colour based form of the pre-RT dental status. A contouring of the teeth will be performed and the planned dose for each tooth of each subject will be recorded by a dose volume histogram (DVH) curve based on the pre-treatment imaging. In the same way the mean dose and the V25 (the volume receiving 25 Gy) of the homo- and the heterolateral parotid gland will be calculated. Based on our predictive model, every tooth which potentially will receive more than 40 Gy and for which long term survival is compromised will be avulsed at least 2 weeks before the start of RT.

After RT, the subject will have clinical follow-up with dental evaluation every 6 months for 36 months in order to identify possible dental events. At each consultation, a stomatological examination will be performed as well as two bitewing radiographs. An orthopantomogram will be done once a year. Furthermore, periapical X-rays will be performed if there is a dental complain or to refine a lesion visible on orthopantomogram.

Inclusion Criteria:

1. Age ≥ 18 years old
2. ECOG performance status ≤2
3. Female and Male
4. Newly diagnosed, histologically or cytologically confirmed head and neck squamous cell carcinoma (oropharynx, oral cavity, larynx, hypopharynx or cavum)
5. Results of previous pre-treatment imaging (PET-CT and cervicofacial MRI and/or CT/scan)
6. Eligible for treatment based on (chemo-)radiotherapy (with or without a surgical treatment)
7. Agree to wear, three times per week, fluoride dental splint after RT
8. HPV/p 16 testing results available at the time of screening (only for subjects with oropharynx cancer)
9. Serum pregnancy test (for subjects of childbearing potential) negative within 7 days prior to the 1st radiotherapy treatment
10. Women of childbearing potential must agree to use of one effective method of contraception prior study entry and during the course of the study.
11. Completion of all necessary screening procedures within 30 days prior to 1st radiotherapy treatment.
12. Signed Informed Consent form (ICF) obtained prior to any study related procedure.
13. Ability to understand and complete the questionnaires (language proficiency, cognitive functioning) as judged by the principal investigator upon screening

Note: Subject from the SwallPEG trial can participate in the StomRay study if they meet all of the previous eligibility criteria.

Exclusion Criteria:

1. Subject having less than ten teeth on dental arch
2. Life expectancy less than 12 months
3. History of previous head and neck irradiation
4. Prior or current treatment with bisphosphonates or denosumab
5. Presence of too many metal artefacts on the RT simulation scan preventing precise teeth contouring
6. Subject with a significant medical, neuro-psychiatric, or surgical condition, currently uncontrolled by treatment, which, in the principal investigator's opinion, may interfere with completion of the study.
7. Pregnancy and/or lactating women
8. Subjects with imperfect amelogenesis