Prognostic value of 18F-FDG PET/CT performed before reirradiation of head and neck squamous cell carcinoma recurrence
OC-0948
Abstract
Prognostic value of 18F-FDG PET/CT performed before reirradiation of head and neck squamous cell carcinoma recurrence
Authors: François Lucia1, Alicia Vu2, Vincent Bourbonne1, Coralie Clodic3, Jean-Christophe Leclerc3, Olivier Pradier4, Ronan Abgral5, Ulrike Schick4
1University hospital of Brest, Radiation therapy, Brest, France; 2University hospital of Brest, Radiation Therapy, Brest, France; 3University hospital of Brest, Head and neck Surgery, Brest, France; 4University Hospital of Brest, Radiation therapy, Brest, France; 5University Hospital of Brest, Nuclear medicine, Brest, France
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Purpose or Objective
Up to 50% of patients treated with radiotherapy (RT) with a curative intent for a head and neck squamous cell carcinoma (HNSCC) will present a loco-regional recurrence or a second primary tumor. When salvage surgery is not possible, re-irradiation (reRT) should be discussed. As the benefit-risk balance is uncertain, biomarkers to select patients are needed. The purpose of this study was to establish the prognostic value of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) features before reRT of patients with a loco-regional HNSCC recurrence.
Material and Methods
Patients who underwent a 18F-FDG PET/CT before reRT for a loco-regional HNSCC recurrence between 2012 and 2020 were retrospectively included. A gross tumor volume (GTV) corresponding to primary disease with nodal disease if present was segmented using a gradient-based method (PET-Edge) embedded in MIM Maestro© v7.0 (MIM©, Cleveland, OH, USA). From each volume, maximum standardized uptake value (SUVmax), peak of SUV (SUVpeak), mean of SUV (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum tumor to blood ratio (TBRmax) and maximum tumor to liver ratio (TLRmax) were calculated. Usual clinical features at the time of recurrence were collected and analyzed. A cox regression-based model was developed for the prediction of overall survival (OS) and also evaluated for the prediction of disease local control (LC) and disease-free survival (DFS).
Results
Thirty patients met inclusion criteria with a median follow up of 6.5 months (range 1-38 months). Median OS, LC and DFS were 6 months (95CI% 3-12 months), 4 months (95CI% 2-6 months) and 3 months (95CI% 2-6 months), respectively. MTV (p=0.007), TLG (p=0.028), tumor recurrence site (p=0.022) and head and neck organ dysfunction (HNOD) (p=0.018) were significantly correlated with OS. MTV (p=0.045) and tumor recurrence site (p=0.016) remained independent significant prognostic factors of OS after multivariate analysis. When these 2 parameters were logistically combined, the model significantly stratified patients at low and high-risk for OS (HR=3.4; 95%CI 1.5-7.7), LC (HR=3.6; 95%CI 1.3-9.8) and DFS (HR=3.2; 95%CI 1.3-7.7).
Conclusion
MTV volumetric PET parameter and tumor recurrence site may be significant prognostic factors in patients reirradiated for a head and neck relapse. These findings need to be confirmed in prospective and larger populations, but could help clinicians for a better selection of patients eligible for reRT.