Comparative effectiveness and stage-shift effect of endoscopic exam among newly diagnosed oral cancer patients with different stages in Taiwan.

BACKGROUND: Patients with oral cancer are at higher risk of developing second primary esophageal cancer (SPEC) and the consensus for screening strategies remains unclear. This study aimed to examine comparative effectiveness and the stage-shift effect of endoscopic exam among patients with oral cancer. METHOD: A population-based longitudinal retrospective observational matched case and control cohort study with at least 5 years follow-up was conducted. We identified 45 457 newly diagnosed patients with oral cancer, 2004-2013, and the eligible patient with oral cancer was 39 401. Propensity score matching was used to match comparable groups, and the two groups (screening vs. nonscreening) was 5941, individually. The study primary endpoints were to compare detection of incident SPEC and the stage-shift effect of endoscopic screening between screened and nonscreened incident oral cancer patients. Cox proportional hazard and competing risk models were analyzed. Statistical analyses were conducted in 2020-2021. RESULT: Detection of incident SPEC in the screened group was significantly higher than in the nonscreened group (hazard ratio: 2.92, 95% confidence interval [CI]: 2.29-3.72). The stage-shift effect from endoscopic screening was found overall in patients with oral cancer (odds ratio [OR]: 0.39, 95%CI: 0.21-0.70), in particular in advanced-stage patients (OR: 0.25, 95%CI: 0.11-0.61), but not in early-stage patients (OR: 0.60, 95%CI: 0.26-1.40). CONCLUSION: This study confirmed that endoscopic screening achieved early detection of SPEC among patients with oral cancer. To improve the screening stage-shift effect, patients with oral cancer are encouraged to undergo routine endoscopic screening.