Assessment of tumor response to chemoradiotherapy and predicting prognosis in patients with head and neck squamous cell carcinoma by PERCIST

Purpose: To evaluate therapeutic response to chemoradiotherapy and prediction of recurrence and death in patients with head and neck squamous cell carcinoma (HNSCC) using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST). Materials and methods: Forty-two patients (mean 63.4, range 20–79 years) with nasopharyngeal (n = 10), oropharyngeal (n = 13), hypopharyngeal (n = 11), or laryngeal (n = 8) cancer underwent fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) before and approximately 3 months (mean 95.0, range 70–119 days) after undergoing concurrent chemoradiotherapy. The effect of PERCIST regarding progression-free survival (PFS) and overall survival (OS) was examined using log-rank and Cox methods. Results: Complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), and progressive metabolic disease shown by PERCIST were seen in 30 (71.4%), 9 (21.4%), 3 (7.1%), and 0 patients, respectively. Fourteen (33.3%) developed recurrent disease (median follow-up 27.2, range 8.7–123.1 months) and 9 (21.4%) died (median follow-up 43.6, range 9.6–132.6 months). Furthermore, 4 (13.3%) of 30 patients with CMR developed recurrence, while 7 (77.8%) of 9 with PMR and all 3 (100%) with SMD developed recurrence. Two (6.7%) of 30 patients with CMR, 4 (44.4%) of 9 with PMR, and all 3 (100%) with SMD died. Patients who achieved CMR showed significantly longer PFS and OS as compared to those who did not (PMR and SMD) (both, p < 0.0001). Conclusion: PERCIST is useful for evaluating therapeutic response to chemoradiotherapy and predicting recurrence and death in HNSCC patients.