Non-smoking and Non-drinking Oral Cancer Patients Are at Higher Risk of Second Primary Tumours.

Objectives: This study aimed to explore differences in demographics, tumour characteristics and outcomes in oral squamous cell carcinoma (OSCC) patients with a history of non-smoking, non-drinking (NSND) versus smoking and/or drinking (SD).

Materials and methods: Newly diagnosed OSCC patients undergoing curative surgical treatment were prospectively included in OncoLifeS, a data biobank. Cox regression analysis was performed yielding hazard ratios (HRs) and 95% confidence intervals (95%CIs).

Results: 185 patients were included, and 32.4% of patients were NSND; this group represented an older (69 vs. 64.4 years, p < 0.01) and more female-dominated (66.7% vs. 44.5%, p = 0.02) population. NSND patients had more tongue tumours (68.3% vs. 46.4%, p < 0.01) and few floor-of-mouth tumours (1.7% vs. 20.0%, p < 0.01). Locoregional recurrence, overall survival and disease-specific survival risk were similar between the NSND and SD patients. NSND patients had a higher second primary tumour risk compared to SD patients in the multivariable analysis (adjusted HR 3.92, 1.23-12.48, p = 0.02).

Conclusion: NSND patients with OSCC have a distinct clinicopathological profile compared to SD patients, with a higher risk of second primary tumours after treatment. These differences in risk profiles should be considered in future OSCC management strategies.