[The value of induction chemotherapy in the treatment of loco-regionally advanced tonsil squamous cell carcinoma].

Objective: To investigate the response to induction chemotherapy (IC) as prognostic indicators for radiotherapy response and survival outcomes in patients with loco-regionally advanced tonsil squamous cell carcinoma (LATSCC). Methods: A retrospective analysis was conducted on 84 LATSCC patients who were admitted to the Eye & ENT Hospital of Fudan University. There were 67 males and 17 females, aged from 42 to 76 years. Among them, 55 patients (65.5%) were p16 positive and 29 patients (34.5%) were p16 negative. All patients received initial IC with TPF chemotherapy regimen (docetaxel+cisplatin+capecitabine) followed by either radiotherapy alone or concurrent chemoradiotherapy. The differences in categorical variables were compared using Chi-square test and Fisher exact test. Logistic regression was employed to identify independent factors associated with radiotherapy sensitivity. Kaplan-Meier method was utilized to calculate cumulative survival, while Log-rank test and Cox risk model were performed for univariate and multivariate analyses of overall survival (OS), locoregional relapse-free survival (LRFS), and distant metastasis free survival (DMFS). Results: After IC, the objective response rates (ORR) in p16 positive group and p16 negative group were 87.3% and 89.7%, respectively (χ2=0.103, P=0.749). Following radiotherapy, the complete response rates in p16 positive group and p16 negative group were 87.3% and 72.4%, respectively (χ2=5.058, P=0.115). Sensitivity to IC (OR=10.883, 95%CI: 2.555-45.930, P=0.001) was independently associated with complete response to radiotherapy and in the p16 positive group, the 3-year OS, LRFS, and DMFS were 90.0%, 81.5%, and 96.4%, respectively. In the p16 negative group, they were 82.1%, 89.1%, and 92.0%, with no statistically significant difference in the rates between two groups(P>0.05). Compared to IC-resistant patients, IC-sensitive patients showed significant improvements in 3-year LRFS (90.2% vs. 40.0%, χ2=19.750, P<0.001). IC resistance was identified as an independent risk factor for LRFS (HR=2.180, 95%CI=1.235-3.849, P=0.007). Conclusions: The response to IC is a significant prognostic factor for tonsil squamous cell carcinoma treated with definitive radiotherapy. Poor response to IC is associated with unsatisfactory outcomes either in p16-positive or p16-negative cancer.