Association of Body Mass Index with Survival Outcome in Patients with Head and Neck Cancer Treated with Combined Modality Therapy

Purpose/Objective(s) Combined modality therapy with surgery, chemotherapy, and/or radiation often results in significant morbidity among patients with head and neck cancer, including dysphagia and weight loss. Given extensive side effect profiles, body mass index (BMI) has been shown to play a role in the clinical outcome of such patients. To validate this finding, we performed an observational cohort study to investigate BMI and its association with survival outcomes in patients with head and neck cancer treated with multimodal therapies. Materials/Methods A single-institution, retrospective database was queried for patients with non-metastatic head and neck cancer who underwent either definitive-intent chemoradiation or postoperative radiation therapy from 1/2005 to 4/2021. BMI was stratified by underweight, normal, overweight, and obese by <18.5, 18.5-24.9, 25.0-29.9, and 30.0 or above, respectively. Cox multivariable analysis (MVA) and Kaplan-Meier method were used to analyze overall survival (OS) and cancer-specific survival (CSS) outcomes. Logistic MVA was performed to identify variables associated with post-treatment responses. Propensity score matching was used to construct matched pairs based on nearest neighbor method in a 1:1 ratio with no replacement. Results A total of 738 patients (n=206 with normal BMI, n=27 with underweight, n=274 with overweight, and n=231 with obese BMI) were included for analysis. Median follow up was 31.0 months (interquartile range 18.5-58.0). On Cox MVA, being overweight was associated with improved OS (aHR 0.70, 95% CI 0.51-0.97, p=0.03), but not CSS (aHR 0.82, 95% CI 0.55-1.22, p=0.34). Similar findings were noted in 163 matched pairs of patients with normal BMI and overweight (OS: HR 0.69, 95% CI 0.48-0.99, p=0.04; CSS: HR 0.80, 95% CI 0.51-1.24, p=0.32). Among 683 patients with available treatment response, being overweight was associated with complete response after treatments (aOR 0.52, 95% CI 0.30-0.90, p=0.02). Being underweight (OS: aHR 0.84, 95% CI 0.49-1.44, p=0.53; CSS: aHR 1.83, 95% CI 0.98-3.41, p=0.06) or obese (OS: aHR 0.77, 95% CI 0.53-1.11, p=0.16; CSS: aHR 0.92, 95% CI 0.58-1.46, p=0.73) was not associated with survival outcomes. Conclusion In this study, being overweight was associated with improved OS and increased likelihood of complete response after treatments, while it had no association with CSS. However, having normal BMI or obesity were not associated with improved survival outcomes. Further studies would be warranted to investigate the role of BMI as a prognostic marker among patients who underwent multimodal therapies. Combined modality therapy with surgery, chemotherapy, and/or radiation often results in significant morbidity among patients with head and neck cancer, including dysphagia and weight loss. Given extensive side effect profiles, body mass index (BMI) has been shown to play a role in the clinical outcome of such patients. To validate this finding, we performed an observational cohort study to investigate BMI and its association with survival outcomes in patients with head and neck cancer treated with multimodal therapies. A single-institution, retrospective database was queried for patients with non-metastatic head and neck cancer who underwent either definitive-intent chemoradiation or postoperative radiation therapy from 1/2005 to 4/2021. BMI was stratified by underweight, normal, overweight, and obese by <18.5, 18.5-24.9, 25.0-29.9, and 30.0 or above, respectively. Cox multivariable analysis (MVA) and Kaplan-Meier method were used to analyze overall survival (OS) and cancer-specific survival (CSS) outcomes. Logistic MVA was performed to identify variables associated with post-treatment responses. Propensity score matching was used to construct matched pairs based on nearest neighbor method in a 1:1 ratio with no replacement. A total of 738 patients (n=206 with normal BMI, n=27 with underweight, n=274 with overweight, and n=231 with obese BMI) were included for analysis. Median follow up was 31.0 months (interquartile range 18.5-58.0). On Cox MVA, being overweight was associated with improved OS (aHR 0.70, 95% CI 0.51-0.97, p=0.03), but not CSS (aHR 0.82, 95% CI 0.55-1.22, p=0.34). Similar findings were noted in 163 matched pairs of patients with normal BMI and overweight (OS: HR 0.69, 95% CI 0.48-0.99, p=0.04; CSS: HR 0.80, 95% CI 0.51-1.24, p=0.32). Among 683 patients with available treatment response, being overweight was associated with complete response after treatments (aOR 0.52, 95% CI 0.30-0.90, p=0.02). Being underweight (OS: aHR 0.84, 95% CI 0.49-1.44, p=0.53; CSS: aHR 1.83, 95% CI 0.98-3.41, p=0.06) or obese (OS: aHR 0.77, 95% CI 0.53-1.11, p=0.16; CSS: aHR 0.92, 95% CI 0.58-1.46, p=0.73) was not associated with survival outcomes. In this study, being overweight was associated with improved OS and increased likelihood of complete response after treatments, while it had no association with CSS. However, having normal BMI or obesity were not associated with improved survival outcomes. Further studies would be warranted to investigate the role of BMI as a prognostic marker among patients who underwent multimodal therapies.