InGReS is a phase I pilot study of adaptive dose-escalated radiotherapy in combination with platinum-based chemotherapy (CRT) for locally advanced head and neck cancer.

InGReS will assess the feasibility of adapting the radiotherapy (RT) plan for each patient, based on anatomical and metabolic changes in the tumour seen on MRI and FDG-PET-CT performed after 2 weeks of CRT in a multicentre setting. The overall aim of the trial is to determine the safety and feasibility of delivering dose-escalated Intensity Modulated Radiotherapy (IMRT) to the residual primary tumour, as seen on intra-treatment imaging, in the final 3 weeks of RT.

The study will recruit 15 patients with locally advanced oropharyngeal or hypopharyngeal squamous cell carcinoma (SCC) who are suitable for primary treatment with concurrent chemo-radiation. The main aim is to see whether it is feasible to perform a FDG positron emission tomography-computed tomography (FDG-PET-CT) and Magnetic Resonance Imaging (MRI) scan after 2 weeks of radiotherapy and re-plan the radiotherapy to escalate the dose of radiotherapy delivered to the residual primary tumour as seen on PET-CT and MRI.

Patients will commence with standard chemo-radiotherapy; 70 Gray (Gy) in 35 fractions with concomitant platinum chemotherapy. After 2 weeks of chemo-radiotherapy patients will have an intra-treatment FDG-PET-CT and MRI scan to assess early response to treatment. Patients with evidence of residual disease will proceed with the dose-escalation phase of the study, with an adaptive radiotherapy re-plan and dose-escalation to the residual primary tumour.

The study will establish acute and late radiotherapy toxicity rates in patients who receive dose-escalated RT, particularly the effect of treatment on long-term swallowing function. The study hypothesis is that mucosal toxicity rates for dose-escalated treatment will be equivalent to those for standard CRT, according to published data. Furthermore, it will also explore whether changes in FDG-PET-CT and MRI during treatment correlate with patient outcomes and potential blood-based biomarkers of treatment response. Local control, disease-free and overall survival will be assessed for both standard and dose-escalated approaches.

Inclusion criteria:

1. Locally advanced, histologically confirmed squamous cell carcinoma (SCC) of the oropharynx and hypopharynx to be treated with primary radical chemo-radiotherapy:

   1. Hypopharyngeal cancer - HPV negative OR HPV positive
   2. Oropharyngeal cancer - EITHER HPV negative OR HPV positive with N stage at least N2b and greater than 10 pack year smoking history: All HPV positive oropharyngeal patients should have at least stage III disease (TNM8)

2. ≥T2 tumours:

3. Staging MRI showing minimum diameter of primary tumour greater than or equal to 1cm

4. Staging 18F-FDG-PET/CT showing adequate uptake in the primary tumour, defined as SUVmax of ≥ 5.0

5. Multidisciplinary team (MDT) decision to treat with primary CRT with curative intent

6. Patients fit for radical treatment with primary CRT

7. WHO Performance Status 0-1

Exclusion criteria:

1. Previous radiotherapy to the head and neck region interfering with the protocol treatment plan
2. Patients requiring neo-adjuvant chemotherapy
3. Inability to tolerate PET or MRI; general contra-indications to MRI
4. Contra-indication to gadolinium
5. Baseline SUVmax < 5.0 in the primary tumour on PET-CT or smaller than 1cm in axial dimensions on cross sectional imaging
6. GFR <40ml/min
7. Previous primary malignancy within 2 years (excluding adequately treated non-melanoma skin cancer, low risk Prostate cancer Gleason 6 or below, carcinoma in situ of cervix).