Role of Post-Treatment 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients Receiving Definitive Chemoradiation for Locally Advanced Head and Neck Squamous Cell Carcinomas

Abstract

Background and Objectives <sup>18</sup>F-fluorodeoxyglucose PET/CT scans can be a useful method to detect recurrence. However, its role in locally advanced head and neck squamous cell carcinomas (HNSCCs) patients after definitive chemoradiotherapy (CRT) has not yet been determined. The current study was performed to identify the role of therapeutic response evaluation using PET/CT after definitive CRT.Subjects and Method We conducted a retrospective review of patients with locally advanced HNSCCs, and who have undergone definitive CRT from 2009 to 2017 at a single institution. The patients were divided into two groups according to their responses to the treatment (metabolic complete remission [mCR] group or non-mCR group), assessed by PET/CT scans after definitive CRT.Results Twenty-eight patients were consecutively enrolled. The most common primary site of cancer was the oropharynx, followed by the oral cavity, hypopharynx, and nasal cavity. The therapeutic response assessed by PET/CT scans was mCR in 14 patients. The median progression- free survival (PFS) was not reached in the mCR group but was 13.3 months for the non-mCR group (<i>p</i>=0.001). The median overall survival was significantly longer for the mCR group (52.5 months) than for the non-mCR group (15.2 months, <i>p</i>=0.002). A multivariate analysis showed PET/CT response and high-sensitivity C-reactive protein (hsCRP) as independent prognostic factors for PFS (mCR: <i>p</i>=0.027; hsCRP: <i>p</i>=0.042) and for the overall survival (mCR: <i>p</i>=0.006; hsCRP: <i>p</i>=0.020).Conclusion PET/CT scans after definitive CRT predicted the prognosis in patients with locally advanced HNSCCs. CRP was a prognostic factor affecting the outcomes of treatments.