Recurrent aphthous stomatitis may be a precursor or risk factor for specific cancers: A case‐control frequency‐matched study

BACKGROUND: Recurrent aphthous stomatitis (RAS) is considered a prophase symptom in patients with specific cancers. This study assessed the association between RAS and subsequent onset of cancer based on a nationwide population‐based database in Taiwan. MATERIALS AND METHODS: We selected study participants from the National Health Insurance Research Database from January 2000 to December 2008. Patients in the non‐RAS cohort were matched to case study patients at a 1:1 ratio through frequency matching. All participants were followed up for at least 5 years, and those who received cancer diagnoses during follow‐up were identified. RESULTS: Among 52 307 patients with and 52 304 patients without RAS, the combined hazard ratio (HR) of all subsequent cancer cases was 1.3 (95% confidence interval [CI]: 1.25‐1.35, P = 0). RAS diagnosis was associated with risk for cancers of the head and neck (aHR = 2, 95% CI: 1.8‐2.3), colon (aHR = 1.2, 95% CI: 1.1‐1.4), liver (aHR = 1.1, 95% CI: 1‐1.3), pancreas (aHR = 1.4, 95% CI: 1.1‐1.7), skin (aHR = 1.4, 95% CI: 1.2‐1.7), breast (aHR = 1.2, 95% CI: 1.1‐1.4), and prostate (aHR = 1.5, 95% CI: 1.3‐1.8), as well as hematologic cancers (aHR = 1.6, 95% CI: 1.3‐1.9). A higher risk was observed for male patients (aHR = 1.35, 95% CI: 1.28‐1.42) than for female patients (aHR = 1.25, 95% CI: 1.18‐1.31) with RAS. CONCLUSIONS: RAS was associated with specific cancers. Susceptible RAS patients should be screened for specific cancers.