Effect of radiochemotherapy on T2* MRI in HNSCC and its relation to FMISO PET derived hypoxia and FDG PET.

Wiedenmann, Nicole; Bunea, Hatice; Rischke, Hans C.; Bunea, Andrei; Majerus, Liette; Bielak, Lars; Protopopov, Alexey; Ludwig, Ute; Büchert, Martin; Stoykow, Christian; Nicolay, Nils H.; Weber, Wolfgang A.; Mix, Michael; Meyer, Philipp T.; Hennig, Jürgen; Bock, Michael; Grosu, Anca L.; Büchert, Martin; Hennig, Jürgen

Background: To assess the effect of radiochemotherapy (RCT) on proposed tumour hypoxia marker transverse relaxation time (T2*) and to analyse the relation between T2* and 18F-misonidazole PET/CT (FMISO-PET) and 18F-fluorodeoxyglucose PET/CT (FDG-PET).Methods: Ten patients undergoing definitive RCT for squamous cell head-and-neck cancer (HNSCC) received repeat FMISO- and 3 Tesla T2*-weighted MRI at weeks 0, 2 and 5 during treatment and FDG-PET at baseline. Gross tumour volumes (GTV) of tumour (T), lymph nodes (LN) and hypoxic subvolumes (HSV, based on FMISO-PET) and complementary non-hypoxic subvolumes (nonHSV) were generated. Mean values for T2* and SUVmean FDG were determined.Results: During RCT, marked reduction of tumour hypoxia on FMISO-PET was observed (T, LN), while mean T2* did not change significantly. At baseline, mean T2* values within HSV-T (15 ± 5 ms) were smaller compared to nonHSV-T (18 ± 3 ms; p = 0.051), whereas FDG SUVmean (12 ± 6) was significantly higher for HSV-T (12 ± 6) than for nonHSV-T (6 ± 3; p = 0.026) and higher for HSV-LN (10 ± 4) than for nonHSV-LN (5 ± 2; p ≤ 0.011). Correlation between FMISO PET and FDG PET was higher than between FMSIO PET and T2* (R2 for GTV-T (FMISO/FDG) = 0.81, R2 for GTV-T (FMISO/T2*) = 0.32).Conclusions: Marked reduction of tumour hypoxia between week 0, 2 and 5 found on FMISO PET was not accompanied by a significant T2*change within GTVs over time. These results suggest a relation between tumour oxygenation status and T2* at baseline, but no simple correlation over time. Therefore, caution is warranted when using T2* as a substitute for FMISO-PET to monitor tumour hypoxia during RCT in HNSCC patients.Trial Registration: DRKS, DRKS00003830 . Registered 23.04.2012.

CHEMORADIOTHERAPY; FLUORODEOXYGLUCOSE F18; HYPOXEMIA; TUMORS; MAGNETIC resonance imaging; PATIENTS

Radiation Oncology, 2018, Vol 13, Issue 1, pN.PAG

1748-717X

Academic Journal

10.1186/s13014-018-1103-1