Prognostic significance of clinical and ¹⁸F-FDG PET/CT parameters for post-distant metastasis survival in head and neck squamous cell carcinoma patients

Introduction: Distant metastasis (M1) to vital organs remains a major cause of death in patients with head and neck squamous cell carcinomas (HNSCC). Clinically the survival periods vary in individual M1 HNSCC patients and a prognostic indicator has not been fully studied. Here, we evaluated the prognostic factors for survival including ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters in M1 HNSCC patients. Methods: The study included 108 patients with newly diagnosed M1 HNSCC (68 during clinical courses, 40 at presentation) who underwent FDG PET/CT. Maximum standardized uptake value (SUVmax) of metastatic tumors was measured by FDG PET/CT. Associations of primary tumor or metastatic tumor variables with overall survival were assessed with Cox regression models. Results: Multivariate analyses demonstrated that nasopharynx primary and incomplete response of loco-regional disease to treatment were significant prognostic factors. In addition, adverse prognostic factors included short distant metastasis-free period (<10 months), high number (≥5), and high PET SUVmax (≥6.3) of metastatic lesions. The patients with at least one of these adverse features had a median survival <14 months. Conclusion: PET SUVmax of the metastatic tumors in M1 HNSCC patients can be a good predictor for survival. J. Surg. Oncol. 2016;114:888–894.