ChemoRT With and Without Dental Stent for Taste Protection in NPC Patients

Primary objective:

Evaluate and compare incidence of acute and long-term taste dysfunction in chemoradiation plus dental stent group vs. chemoradiation group, using objective-measured taste strip test, and patient-reported taste ability and toxicity.

Secondary objectives:

1. Evaluate and compare incidence of acute and long-term toxicities (excluding taste) and patient-reported quality of life between chemoradiation plus dental stent group and chemoradiation group.
2. Evaluate and compare tumor response, overall survival, and failure-free survival between chemoradiation plus dental stent group and chemoradiation group.
3. Analyze dosimetric parameters of taste bud bearing tongue mucosa, ipsilateral/ contralateral parotid and submandibular glands extracted from RT plans and correlate with taste impair

This study is a phase II randomized control trial assessing the efficacy of adding a dental stent for sparing the taste bud and protect the taste sensation in NPC patients undergoing chemoradiation. The enrolled participants will be randomized to add a personalized dental stent during the radical chemoradiation to nasopharynx and neck using IMRT technique. Chemoradiation must begin no later than 4 weeks from the time of recruitment, although treatment as early as possible is highly encouraged.

A total of 50 patients (25 patients each arm) will be accrued to assess the potential benefit and safety of the said dental stent to standard chemoradiation.

All participants will be followed up as follows:

1. One visit before induction chemotherapy (if any)
2. One visit within 6 weeks before RT
3. Weekly during treatment and at the end of treatment (6-7 visits depending on treatment schedule),
4. One visit at 4 weeks post treatment (with +/-2 weeks window period)
5. One visit at 12 weeks post treatment (with +/- 4 weeks window period)
6. One visit at 26 weeks post treatment (with +/-4 weeks window period) and
7. One visit at 52 weeks post treatment (with +/-4 weeks window period) to review their general condition, toxicities, and long-term treatment efficacy and safety profile.

The assessment of taste sensation using subjective questionnaires, alongside objective measures using taste strip tests are performed at baseline, the 12 weeks post treatment follow up and at the 52 weeks post treatment follow up visits.

Eligibility Criteria:
Inclusion Criteria:

1. Patients newly diagnosed with histologically confirmed non-keratinizing NPC.
2. Patients with Tumours staged as T1-4N+/TxN0-3.
3. No sign of distant metastasis (M0).
4. Satisfactory performance status (i.e., Karnofsky Performance Status ≥ 70 or ECOG \< 2)
5. Age 21 years or older.
6. Adequate bone marrow function by peripheral blood counts as demonstrated by the following laboratory values:

   1. ≥ 3 × 109/L leucocytes
   2. ≥ 1.5 × 109/L neutrophils
   3. ≥ 9 g/dL of haemoglobin, and
   4. ≥ 100 × 109/L platelets.
7. Normal liver function demonstrated by the following laboratory values:

   1. Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) concentrations of \< 1.5x upper limit of normal (ULN)
   2. Alkaline phosphatase (ALP) concentration \< 2.5x ULN
   3. Bilirubin \< ULN.
8. Renal function: Creatinine clearance at ≥60 mL/min
9. Able to provide informed consent

7. Induction chemotherapy before radical chemoradiation to nasopharynx and neck is permissible if no disease progression after induction chemotherapy

Exclusion Criteria:

1. Edentulous patients
2. Extensive crown/ implant work to the teeth
3. Patients having basaloid squamous cell carcinoma or WHO keratinizing squamous cell carcinoma.
4. Patients who suffered from previous malignancies, except adequately treated basal cell or squamous cell skin cancer, and in-situ cervical cancer.
5. Received RT previously (except for non-melanomatous skin cancers outside the intended RT treatment area)
6. Patients who received previous surgery (except diagnostic) or chemotherapy for the primary tumours or lymph nodes or history of glossectomy.
7. Patient who had a prior diagnosis of diseases effecting saliva secretion or causing salivary glands impairment (i.e., Sjogren's syndrome, iodine cancer treatment), had a reported history of abnormal sense of taste or eating disorders.
8. Current heavy smokers (smoke \> 1 pack/day) or previous heavy smokers (stopped smoking less than 2 years and had smoked \> 1 pack/day).
9. Patients suffering from any severe intercurrent disease, which may incur unacceptable risk or negatively affect trial compliance. For example, unstable cardiac disease necessitating treatment, chronic hepatitis renal disease, poorly controlled diabetes (fasting plasma glucose greater 1.5x upper limit of normal), and emotional disturbance.
10. Pregnant or lactating women.
11. Inability to attend the full course of RT or planned follow-up/survey responses.