The association between body mass index and efficacy of pembrolizumab as second‐line therapy in patients with recurrent/metastatic head and neck squamous cell carcinoma

BACKGROUND: Recent evidence suggested a potential correlation between BMI and the efficacy of immune checkpoint inhibitors in cancer patients. This study aimed to evaluate the prognostic value of the body mass index (BMI) in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients treat with pembrolizumab. METHODS: The current retrospective cohort study enrolled 49 R/M HNSCC patients underwent at least one cycle of pembrolizumab as second‐line treatment from June 2018 to October 2020. Survival analysis of immunotherapy prognosis and risk factor analysis of age, gender, BMI, ECOG‐PS, CPS, rT‐stage, tumor site, and tube feeding. RESULTS: Among the 49 patients, the BMI at the time of immunotherapy ranged from 14.5 to 32.0 kg/m(2). The Kaplan–Meier analysis showed that the BMI was significantly correlated with overall survival time (OS, p = 0.0007) and progression‐free survival time (PFS, p = 0.0012). BMI, gender, prior treatment, serum albumin level, ECOG‐PS, CPS and rT‐stage were analyzed in multivariate Cox regression model analysis after adjusted for potential confounding clinical variables. Patients with underweight (OS:HR = 6.862, 95% CI:1.566–30.064, p = 0.011; PFS:HR = 5.672, 95% CI:1.364–23.586, p = 0.017);ECOG≥2 (OS:HR = 0.250, 95% CI:0.086–0.731, p = 0.011;PFS:HR = 0.284, 95% CI:0.101–0.805, p = 0.018); CPS <1(OS: HR = 4.34, 95% CI:1.271–15.464, p = 0.019; PFS:HR = 3.859, 95% CI:1.180–12.618, p = 0.025) and rT4‐stage(OS:HR = 4.380, 95% CI:1.452–13.209, p = 0.009;PFS: HR = 3.799, 95% CI:1.240–11.638, p = 0.019) suffered higher risk of mortality. CONCLUSIONS: The BMI at the time of clinical diagnosis was showed to be an independent predictive factor for R/M HNSCC patients receiving pembrolizumab. Compared with normal weight patients, underweight patients have worse clinical prognosis.