Image Assisted Optimization of Proton Radiation Therapy in Chordomas and Chondrosarcomas

Study Overview
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Brief Summary
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Rationale: Chordomas and chondrosarcomas located in the axial skeleton are malignant neoplasms of bone. These tumors share the same clinical challenges, as the effect of the disease is more a function of their local aggressiveness than their tendency to metastasize (20% metastasize). The local aggressive behavior can cause debilitating morbidity and mortality by destruction of nearby located critical neurovascular structures. Imaging has, in addition to histopathology, a role in diagnosis and in guiding (neo)adjuvant and definitive treatment. Despite the low sensitivity to radiotherapy, proton radiotherapy has been successfully used as an adjunct to resection or as definitive treatment for aggressive chordomas and chondrosarcomas, making it a standard indication for proton therapy in the Netherlands. Chordomas and chondrosarcomas consist, especially after previous therapy, of non-viable and viable tumor components. Identification of these viable components by functional imaging is important to determine the effect of previous therapy, as change in total tumor volume occurs more than 200 days after change of functional imaging parameters. Objective: The main objective of this study is to determine if functional MRI parameters change within 6 months, and earlier than volumetric changes after start of proton beam therapy. This would allow timely differentiation between affected and unaffected (viable) tumor components, which can be used for therapy adjustment. Secondary objectives: Determine which set of parameters (PET-CT and secondary MRI) can predict clinical outcome (tumor specific mortality, development of metastases, morbidity secondary to tumor activity and morbidity secondary to treatment); determine what type of imaging can accurately identify viable tumor nodules relative to critical anatomical structures; improving understanding of relevance of changing imaging parameters by correlating these with resected tumor. Study design: Prospective cohort study Study population: LUMC patients diagnosed with primary or recurrent chordoma or chondrosarcoma in the axial skeleton. A number of 20 new patients per year is expected. Main study parameters: Volumetric and functional MR imaging parameters including permeability parameters. Secondary parameters are generated by PET-CT (SUV, MTV and TLG), MR (perfusion, permeability and diffusion), therapy (proton beam dose mapping, surgery) and clinical outcome. End points are disease specific survival, progression free survival (including development of metastases), side effects of treatment, and functional outcome (see CRF). In patients who are treated with surgical resection following neo-adjuvant therapy, the surgical specimen will be correlated with imaging findings. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Treatment and clinical management will not be affected in this study, thus the additional burden, risks, and benefits associated with participation in this study are minimal. Two extra MRI and one PET-CT examination will be planned during proton therapy.

Official Title
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Defining Optimal Imaging Strategies for Diagnosis, Treatment, and Treatment Evaluation of Chordomas and Chondrosarcomas of the Axial Skeleton

Conditions
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Bone Neoplasm of Vertebral Column, Chordoma, Chondrosarcoma, Magnetic Resonance Imaging, PET-CT, Proton Therapy

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Histologically diagnosed with primary or recurrent chordoma or chondrosarcoma in the axial skeleton (clivus, spine and sacrum) Accepted for standard proton beam therapy Exclusion Criteria: Diagnosis other than chordoma or chondrosarcoma is made. Patient refuses (parts) of the standard treatment protocol. Patient refuses MRI due to claustrophobia. Patient not suitable for MRI due to the presence of MRI incompatible implants. Incapacitated patients. Patient doesn't allow coded data to be used for analysis. Patient is under 50 years of age. Lesion size less than 1cm. Patients with WHO 3 and higher.

Ages Eligible for Study
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Minimum Age: 50 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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vp(max), Vp(min) | MRI permeability parameter - tumor plasma volume | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rel Enhancement (%) | MRI perfusion parameter showing the signal enhancement of a pixel of certain dynamic relative to that same pixel in the reference dynamic. The reference dynamic is normally the first, pre-contrast dynamic. | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Max Enhancement (%) | MRI perfusion parameter showing difference between peak intensity S1 and S0. | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Max Rel Enhancement (%) | MRI perfusion parameter showing maximum of all relative enhancements over all dynamics | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Time of arrival T0 (s) | MRI perfusion parameter showing time at which the signal intensity increases for at least 20% compared to the baseline (referred to as initial signal intensity S0). The baseline is the average of the signal intensities of all timepoints before the contrast uptake starts. | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Time To Peak (s) | MRI perfusion parameter showing time till contrast agent bolus reaches peak intensity | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Wash In Rate (sˉ¹) | MRI perfusion parameter showing maximum slope between T0 and time of peak intensity T1 | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Wash Out Rate (sˉ¹) | MRI perfusion parameter showing maximum slope between time of peak intensity T1 and the end of the measurement | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Brevity of Enhancement (s) | MRI perfusion parameter showing time between point of maximum wash in rate and maximum wash out rate. | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Ktrans | MRI permeability parameter - transfer constant between blood plasma and Extravascular Extracellular Space (EES), also called vascular permeability | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| kep | MRI permeability parameter showing rate between EES and blood plasma (also called Tracer Efflux Rate) | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Ve | MRI permeability parameter showing Extravascular Volume fraction (Leakage space); defined as Ktrans / kep | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| Area under the curve (AUC) | MRI permeability and perfusion parameter showing area Under the Curve of all time curves | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| mean ADC, Min ADC, Max ADC | MRI diffusion parameters | At inclusion, 4 and 8 weeks, 5,11,17 and 23 months after the start date of proton therapy treatment | 
| SUV | Standard uptake value extracted from PET-CT imaging | At inclusion and and 11 months following the start date fo proton therapy | 
| MTV | Metabolic tumor volume extracted from PET-CT imaging | At inclusion and and 11 months following the start date fo proton therapy | 
| TLG | Total lesion glycolysis extracted from PET-CT imaging | At inclusion and and 11 months following the start date fo proton therapy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Chordoma, Chondrosarcoma, MRI, PET-CT, Proton therapy