Prognostic impact of pathological complete remission after preoperative irradiation in patients with locally advanced head and neck squamous cell carcinoma: re-analysis of a phase 3 clinical study

PURPOSE: The purpose of this study was to determine the associations between pathological complete remission (pCR) and clinical outcomes in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) who received preoperative radiotherapy or chemoradiotherapy in a phase 3 clinical study. METHODS: A total of 222 newly diagnostic stage III/IVM0 HNSCC patients were randomly assigned to a preoperative concurrent chemoradiotherapy group (n = 104) or preoperative radiotherapy alone group (n = 118). Over a mean follow-up of 59 months, 72 patients were defined as non-responders to preoperative therapy and subsequently underwent resection of the primary lesion with or without neck dissection. The relationship between the pathological tumor response of the primary lesion and treatment prognosis was analyzed. Kaplan–Meier and Cox regression multivariate analyses were performed to evaluate the impact of pCR on local control (LC), overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). RESULTS: Among the 72 non-responders, 25 patients, 10 in the chemotherapy group and 15 in the radiotherapy group, achieved pCR. The 5-year LC, OS, PFS, and DMFS of pCR patients and non-pCR patients were 93.2% vs. 67.7% (p = 0.007), 83.3% vs. 39.7% (p = 0.0006), 76.1% vs. 44.0% (p = 0.009), and 90.4% vs. 56.3% (p = 0.005), respectively. In multivariate analysis, pCR is also an independent prognostic factor in prognosis, with statistically significant differences. CONCLUSION: pCR after preoperative radiotherapy or concurrent chemoradiotherapy is a good prognostic factor in locally advanced HNSCC. TRIAL REGISTRATION: Number:ChiCTR-TRC-114004322 Date:05 Mar, 2014