Newly Diagnosed Oral Cancer Stage and Time from Diagnosis to Treatment in the Pre-COVID-19 and Early COVID-19 Periods: A Nationwide Cohort Study

Background: During the COVID-19 pandemic, patients’ willingness to seek medical attention decreased. Patients with precancerous lesions may have missed out on opportunities for early detection. This affected the time to the initiation of treatment for patients with oral cancer. This study examined whether patients with oral cancer were less likely to be at early cancer stages and analyzed whether the time from the diagnosis to the initiation of treatment was delayed during the pandemic. Methods: This retrospective study analyzed data from the Taiwan National Health Insurance Research Database, Cancer Registry File, and Multiple Cause of Death File. Patients who received new diagnoses of oral cancer were divided into a pre-COVID-19 group (2018) and an early COVID-19 group (2020). Propensity score matching was performed between the two cohorts. Conditional logistic regression analyses were conducted to evaluate the risks of an early-stage oral cancer diagnosis and treatment delay from diagnosis to treatment initiation in the two periods. Results: The odds ratio (OR) for early cancer staging among patients with oral cancer in the early COVID-19 period was 0.89 (95% CI: 0.82–0.96) compared to the pre-COVID-19 period. The OR for delayed treatment among patients with oral cancer in the early COVID-19 period compared with that in the pre-COVID-19 period was 0.95 (95% CI: 0.86–1.05; p = 0.337). Conclusions: The early COVID-19 period was associated with a higher risk of advanced cancer staging, and we did not find a significant association with a delay in the initiation of treatment among patients with oral cancer in Taiwan.