Dose-Effect Relation of Salivary Gland Irradiation

Study Overview
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Brief Summary
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Optimization of radiotherapy to reduce xerostomia is difficult, because many gland locations cannot be seen with current imaging modalities and biological dose-effect are currently insufficiently understood. PSMA PET is a new diagnostic instrument which can visualize the presence of vital acinar cells in salivary gland locations throughout the head and neck, with a sensitive and quantitative signal. A reduction of PSMA accumulation in salivary glands is thought to correlate with loss of vital acinar cells. The PET images can be correlated with radiotherapy dose distributions in gland-based or voxel-based evaluations. This makes PSMA PET a suitable instrument to derive the radiobiological dose-effect relations that are required to develop better and gland-specific dose constraints for radiotherapy. The results of this study can contribute to lower toxicity and better quality of life in patients treated with high-dose radiotherapy in the head and neck.

Detailed Description
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Primary objective of this prospective observational study is to determine the gland-based dose-effect relation between conventionally fractionated radiotherapy (RT) and long-term loss of acinar cells, per salivary gland type. The study population consists of a maximum of 20 patients with HNSCC referred for high-dose (CC)RT. There is no therapeutic intervention. Diagnostic intervention is PSMA PET/CT.

Official Title
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Determining the Dose-Effect Relation of Salivary Gland Irradiation and Cell Loss With PSMA PET

Conditions
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HNSCC

Intervention / Treatment
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* Device: PSMA PET/CT-scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: HNSCC of the head-neck area, cTx-4 N0-3 M0 Accepted for EBRT in a conventionally fractionated schedule of 6-7 weeks. Exclusion Criteria: Age <18y Pregnancy or lactation Participation in conflicting studies, e.g. with non-standard treatment and/or imaging Inability to provide informed consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| RT with curative intent for HNSCC<br>several schemes for radical (chemo)radiotherapy, administered in 30-35 fractions over 6-7 weeks | Device: PSMA PET/CT-scan<br>* PSMA PET is a new diagnostic instrument which can visualize the presence of vital acinar cells in salivary gland locations throughout the head and neck, with a sensitive and quantitative signal.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the mean received radiation dose to salivary glands (Dmean), and the total uptake of PSMA in salivary glands (SUVtotal) and its relative reduction after radiotherapy (ΔSUVtotal-6). | Dmean and ΔSUVtotal-6 are correlated to determine the dose-effect relation. | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ΔSUV |  | 1 month | 
| the clinical evaluation of a dry mouth | according to the C30+HN35 QoL | before treatment, once during 7 weeks of treatment and follow up 6 months after | 
| the clinical evaluation of a dry mouth | Groningen questionnaires | before treatment, once a week during 7 weeks of treatment and follow up 6 months after | 
| voxel-based ΔSUV |  | 7 weeks of treatment, follow-up 1 and 6 months | 
| Voxel-based received radiation dose |  | 7 weeks of treatment, 1 and 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Head-neck tumours, Radiotherapy, Salivary gland toxicity, PSMA PET/CT