Twenty-seven years of primary salivary gland carcinoma in Wales: an analysis of histological subtype and associated risk factors.

OBJECTIVE: Risk factors for salivary gland carcinoma are poorly understood. Although links between background radiation, smoking and obesity have been previously suggested, no studies have so far established any significant results. This study aimed to establish correlations between common environmental and lifestyle risk factors and different subtypes of salivary gland carcinoma. METHOD: A study of population data in Wales spanning 27 years was conducted; 2 national databases were used to identify 356 cases of primary salivary gland carcinoma over this period. Histological subtype of cancer and geographical location of each case was recorded. Public health data was used to establish radon levels, smoking, obesity and activity levels of populations in each geographical location. A population matched multivariate analysis of variance analysis was performed using histological subtype and risk factor data for each geographical location. RESULTS: A significantly higher incidence of mucoepidermoid cancer in populations with higher background radon levels (p = 0.006), epithelial-myoepithelial cancer in populations with higher smoking levels (p = 0.029) and adenoid cystic cancer in populations with higher obesity levels (p = 0.028) was found. CONCLUSION: To the authors' knowledge, this is the first study to establish significant links between background radiation, smoking and obesity with different subtypes of salivary gland carcinoma.