The impact of induction chemotherapy response to survival outcomes in oropharyngeal cancer.
Authors: Qixian Zhang, Xin Zhou, Tingting Xu, Chunying Shen, Hongmei Ying, Xiayun He, Yu Wang, Qinghai Ji, Chaosu Hu, Xueguan Lu
Journal: Journal of Clinical Oncology (2022)

6040 Background: The role of induction chemotherapy (IC) in oropharyngeal squamous cell carcinoma (OPSCC) remains inconclusive. Previous randomized trials showed no survival advantage with IC in head and neck squamous cell carcinoma, including OPSCC. However, the impact of response to IC has rarely been considered in these trials. In this study, we aimed to investigate the prognostic value of IC response on HPV+ and HPV- OPSCC. Methods: Patients with stage II-IVB OPSCC (UICC 7 th edition) who underwent IC (paclitaxel and platinum-based regimen for the most) and concurrent chemoradiotherapy during 2010 to 2020 were enrolled. HPV status was confirmed by p16 immunohistochemistry (p16 ≥ 70%). The clinical response to IC was assessed on MRI or CT images. Patients with complete response (CR) or major partial response (PR) (≥50% PR) were defined as sensitive subgroup (IC-s), while those with &lt;50% PR, stable disease (SD) or progressive disease (PD) were deemed as resistant (IC-r). Progression-free survival (PFS) and overall survival (OS) were compared. Results: 51 HPV+ and 57 HPV- OPSCC patients were included. In the entire cohort, 55.6% patients were sensitive to IC. HPV+ OPSCC showed higher IC-s rate (62.7% vs. 49.1%) than HPV- subgroup. IC-s was associated with better clinical outcomes either in the whole cohort (3y-PFS 91.7%vs.43.7%, P &lt; 0.001; 3y-OS 98.3% vs.67.4%, P = 0.002), the HPV+ subgroup (3-year PFS 94.7% vs. 47.9%, P &lt; 0.001; 3-year OS 100% vs. 73.5%, P = 0.055) or the HPV- subgroup (3-year PFS 88.2% vs. 40.9%, P = 0.001; 3-year OS 96.4% vs. 63.1%, P = 0.026). Multivariate analysis demonstrated IC-s as an independent prognosticator for 3y-PFS (hazard ratio [HR], 0.088; 95% confidence interval [CI], 0.027-0.289; P &lt; 0.001) and 3y-OS ([HR], 0.100; 95% CI, 0.021-0.477; P = 0.004) when adjusting for T, N, gender, age and smoking status. Conclusions: The response to IC exerts a critical predictive effect on survival outcomes in both HPV+ and HPV- OPSCC. Personalized treatment strategy based on IC response warrants further exploration in future studies. Response to induction chemotherapy. All patients (n = 108) HPV+ patients (n = 51) HPV- patients (n = 57) OP LN OP+LN OP LN OP+LN OP LN OP+LN IC-s, n (%) 84 (77.8%) 64 (59.3%) 60 (55.6%) 44 (86.3%) 34 (66.7%) 32 (62.7%) 40 (70.2%) 30 (52.6%) 28 (49.1%) CR 45 (41.7%) 21 (19.4%) 12 (11.1%) 26 (51.0%) 13 (25.5%) 7 (13.7%) 19 (33.3%) 8 (14.0%) 5 (8.8%) Major PR 39 (36.1%) 43 (39.8%) 48 (44.4%) 18 (35.3%) 21 (41.2%) 25 (49.0%) 21 (36.8%) 22 (38.6%) 23 (40.4%) IC-r, n (%) 24 (22.2%) 44 (40.7%) 48 (44.4) 7 (13.7%) 17 (33.3) 19 (37.3%) 17 (29.8) 27 (47.4%) 29 (50.9%) Minor PR 14 (13.0%) 18 (16.7%) 20 (18.5%) 2 (3.9%) 5 (9.8%) 5 (9.8%) 12 (21.1%) 13 (22.8%) 15 (26.3%) SD 9 (8.3%) 25 (23.1%) 27 (25.0%) 5 (9.8%) 12 (23.5%) 14 (27.5%) 4 (7.0%) 13 (22.8%) 13 (22.8%) PD 1 (0.9%) 1 (0.9%) 1 (0.9%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (1.8%) 1 (1.8%) 1 (1.8%) Abbreviation: OP = oropharynx; LN = lymph node; ORR = objective response rate.