Finding an oral potentially malignant disorder in screening program is related to early diagnosis of oral cavity cancer - Experience from real world evidence

Objectives: Our study evaluates the effectiveness of the Taiwan Oral Mucosal Screening (TOMS) program in stage-shift among oral cavity cancer patients, and identifies the related factors with early cancer diagnosis. Materials and methods: This retrospective cohort study used the Taiwan Cancer Registry (TCR), TOMS and Taiwan Death Registry (TDR) databases. We identified oral cavity cancer patients (ICD-C-O: C00-C06) from the TCR during 2012-2015. Patients' screening history, first screening status and subsequent screenings were analyzed with cancer stages and survival outcomes. Results: The 5-year survival rates for stages 0-4 were 83.9%, 82.1%, 72.7%, 60.1% and 38.0%. Among 18,625 patients identified from the TCR, 37% did not have any prior screenings. Patients with prior positive or negative screenings all had better survival rates (3-year: 71.4% and 68.7% vs. 63.5%, Log-rank p-value < 0.0001). The best chance for early-stage diagnosis occurs in oral potentially malignant disorder (OPMD, OR = 1.99, 95% CI = 1.78-2.22, p < 0.0001) patients at their first screenings. The hazard ratios (HR) for patients with prior screenings indicated a significant survival benefit. The group of incomplete diagnosis confirmation also has better survival (HR = 0.78, 95% CI = 0.81-0.93, p < 0.0001), and a greater chance of early diagnosis at subsequent screenings. Conclusion: While TOMS improved stage-shift for early cancer diagnosis, we found no obvious differences in participants with cancers at screening (stages 0-1: 26.3% vs. 27.8% in non-screening group). Survival benefit and early diagnosis are found in most of screening groups, and identifying an OPMD is particularly essential to early diagnosis of oral cavity cancer patients.