A case-case study on sinonasal cancer prevention: effect from dust reduction in woodworking and risk of mastic/solvents in shoemaking

Background and aims: Sinonasal cancers (SNCs) are rare neoplasms, accounting for about 3 % of head and neck cancers, with squamous cell carcinoma (SCC) and adenocarcinoma (ADC) as the most common subtypes. ADCs present strong associations with occupational wood dust exposure. Preventive measures have progressively reduced wood dust concentrations in workplaces but no study has evaluated the effectiveness of such interventions. Few studies indicate associations between ADC and exposure to solvents, which is common in the shoe industry, but this hypothesis still needs confirmation. Methods: In a case-case study, we contrasted 32 ADCs against 21 Non-Adenocarcinoma Epithelial Tumors (NAETs) - all recruited from the same clinical setting (Padua's University Hospital; period 2004-2015) - using questionnaires and clinical records to collect information on potential predictors. Non-occupational factors were age, sex, smoking, allergy and chronic sinusitis. Occupational factors were intensity and frequency of wood dust exposure, protection from wood dust, type of wood (in woodworking); frequency of exposure to leather dust or mastic/solvent (in shoemaking). Odds-ratio (OR), 95 % confidence interval (95 % CI) and two-tail p-values were obtained through stepwise backward logistic regression for each industry, always using as reference patients never employed in either trade and adjusting for non-occupational risk factors. Results: Adjusted OR was 22.5 (95 % CI = 3.50-144; p = 0.001) and 9.37 (95 % CI = 1.29-67.6; p = 0.026), respectively, in patients with low or high degree of protection against wood dust. In the shoe industry, adjusted OR was 1 and 18.8 (95 % CI = 1.29-174; p = 0.030), respectively, in patients with low or high exposure to only mastic/solvent; and 1 and 22.5 (95 % CI = 2.07-244; p = 0.011), respectively, in patients with low or high exposure to only leather dust. Discussion and conclusions: The questionnaire used was able to estimate with simple algorithms past exposures in wood and footwear industries. The case-case design considerably increased the validity of this small study. Results in this study were always consistent with the extant literature; this could support reliability of novel findings. In woodworking, respiratory protective equipment and local exhaust ventilation reduced the risk of occupational SNC; in footwear manufacture, where preventive interventions were seldom adopted, SNC risk was significantly greater for high exposure from mastic/solvent and leather dust.