Evolution of the hypoxic compartment on sequential oxygen partial pressure maps during radiochemotherapy in advanced head and neck cancer

Marta Lazzeroni; Ana Ureba; Nicole Wiedenmann; Nils H Nicolay; Michael Mix; Benedikt Thomann; Dimos Baltas; Iuliana Toma-Dasu; Anca L Grosu

doi:10.1016/j.phro.2021.01.011

Evolution of the hypoxic compartment on sequential oxygen partial pressure maps during radiochemotherapy in advanced head and neck cancer

Phys Imaging Radiat Oncol. 2021 Feb 11:17:100-105. doi: 10.1016/j.phro.2021.01.011. eCollection 2021 Jan.

Authors

Marta Lazzeroni^{1

2}, Ana Ureba^{3

2}, Nicole Wiedenmann⁴, Nils H Nicolay⁴, Michael Mix⁵, Benedikt Thomann⁴, Dimos Baltas⁴, Iuliana Toma-Dasu^{1

2}, Anca L Grosu⁴

Affiliations

¹ Department of Physics, Stockholm, Sweden.
² Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
³ Skandion Clinic, Uppsala, Sweden.
⁴ Department of Radiation Oncology, Medical Center, Medical Faculty Freiburg, German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany.
⁵ Department of Nuclear Medicine, University Medical Center, Freiburg, Germany.

Abstract

Background and purpose: Longitudinal Positron Emission Tomography (PET) with hypoxia-specific radiotracers allows monitoring the time evolution of regions of increased radioresistance and may become fundamental in determining the radiochemotherapy outcome in Head-and-Neck Squamous Cell Carcinoma (HNSCC). The aim of this study was to investigate the evolution of the hypoxic target volume on oxygen partial pressure maps (pO₂-HTV) derived from ¹⁸FMISO-PET images acquired before and during radiochemotherapy and to uncover correlations between extent and severity of hypoxia and treatment outcome.

Material and methods: ¹⁸FMISO-PET/CT images were acquired at three time points (before treatment start, in weeks two and five) for twenty-eight HNSCC patients treated with radiochemotherapy. The images were converted into pO₂ maps and corresponding pO₂-HTVs (pO₂-HTV₁, pO₂-HTV₂, pO₂-HTV₃) were contoured at 10 mmHg. Different parameters describing the pO₂-HTV time evolution were considered, such as the percent and absolute difference between the pO₂-HTVs (%HTV_i,j and HTV_i-HTV_j with i,j = 1, 2, 3, respectively) and the slope of the linear regression curve fitting the pO₂-HTVs in time. Correlations were sought between the pO₂-HTV evolution parameters and loco-regional recurrence (LRR) using the Receiver Operating Characteristic method.

Results: The Area Under the Curve values for %HTV_1,2, HTV₁-HTV₂, HTV₁-HTV₃ and the slope of the pO₂-HTV linear regression curve were 0.75 (p = 0.04), 0.73 (p = 0.02), 0.73 (p = 0.02) and 0.75 (p = 0.007), respectively. Other parameter combinations were not statistically significant.

Conclusions: The pO₂-HTV evolution during radiochemotherapy showed predictive value for LRR. The changes in the tumour hypoxia during the first two treatment weeks may be used for adaptive personalized treatment approaches.

Keywords: FMISO PET; HNSCC; Hypoxia; Radiochemotherapy; pO2.