The utility of multiparametric MRI to characterize hypoxic tumor subvolumes in comparison to FMISO PET/CT. Consequences for diagnosis and chemoradiation treatment planning in head and neck cancer

Head and Neck Cancer
17/06/2020

Wiedenmann N, et al. Radiother Oncol 2020.

ABSTRACT

BACKGROUND AND PURPOSE: Hypoxia is an essential metabolic marker that determines chemo- and radiation resistance in head-and-neck squamous cell carcinoma (HNSCC) patients. Our exploratory analysis aimed to identify multiparametric MRI (mpMRI) parameters linked to hypoxia that might be used as surrogate for [18F]FMISO-PET in diagnosis and chemoradiation treatment (CRT) of HNSCC.

MATERIALS AND METHODS: 21 patients undergoing definitive CRT for HNSCC were prospectively imaged with serial [18F]FMISO-PET and 3 Tesla mpMRI for T1- and T2-weighted and dynamic contrast-enhanced perfusion and diffusion-weighted measurements (ktrans, ve, kep, ADC) in weeks 0, 2 and 5 and FDG-PET in week 0. [18F]FMISO-PET-derived hypoxic subvolumes (HSV) and complementary non-hypoxic subvolumes (nonHSV) were created for tumor and lymph nodes and projected on the mpMRI images after PET/MRI image co-registration. mpMRI and [18F]FMISO-PET parameters within HSVs and nonHSVs were statistically compared.

RESULTS: FMISO-PET-based HSVs of the primary tumors on MRI were characterized by lower ADC at all time points (p=0.012 at baseline; p=0.015 in week 2) and reduced interstitial space volume fraction ve and perfusion ktrans at baseline (p=0.006, p=0.047) compared to nonHSVs. Hypoxic lymph nodes were characterized by significantly lower ADC values at baseline (p=0.039), but not at later time points and a reduction in ktrans-based perfusion at week 2 (p=0.018).

CONCLUSION: MpMRI parameters differ significantly between hypoxic and non-hypoxic tumor regions, defined on FMISO-PET/CT as gold standard and might represent surrogate markers for hypoxia. These findings suggest that mpMRI may be useful in the future as a surrogate modality for hypoxia imaging in order to personalize CRT.