Title: Impact of the COVID-19 pandemic on the severity of newly diagnosed cases of head and neck squamous cell carcinoma in southern Brazil

Abstract Purpose Responsible for more than 360 thousand deaths in the world, head and neck squamous cell carcinoma (HNSCC) is an important public health problem worldwide, being more prevalent in men, smokers and alcoholics, aged over 40 years and with lower socioeconomic status. Some of these risk factors are also common to an increased risk of developing severe cases of COVID-19, the pandemic that has been affecting the world since the beginning of 2020. The aim of this study was to retrospectively assess the impact of the COVID-19 pandemic on the HNSCC diagnosis and severity of the disease in a hospital in southern Brazil. Methods All new cases diagnosed with HNSCC from March 11, 2019 to March 10, 2020 (pre-COVID-19 group) and all new cases diagnosed from March 11, 2010 to March 10, 2021 (COVID-19 group) were included. Data were obtained through histopathological reports and medical records. Results There was no difference in the number of new diagnoses in the COVID-19 group (n = 45) compared to the pre-COVID-19 group (n = 47). Patients' sociodemographic profile, time between diagnosis and treatment, and overall TNM staging were similar. However, the clinical N classification was more severe in the COVID-19 group (p = 0.021). Patients diagnosed during the COVID-19 pandemic were 4.05 times more likely to have more severe lymph node involvement (95% CI:1.62–10.12). Conclusion Although there was no reduction in the new diagnosis of HNSCC in the period of greater restriction of COVID-19 pandemic, the diagnosed cases showed lymph node metastasis in more advanced stages.