Occupational risk factors for sinonasal inverted papilloma: a case-control study.

OBJECTIVES: Sinonasal inverted papilloma (IP) is an uncommon benign tumour characterised by frequent recurrence and, in approximately 10% of cases, by neoplastic transformation. IP aetiology is unknown but human papillomavirus is detectable in about one quarter of tumours. As some occupational hazards have been reported to be possible risk factors for IP, the aim of this study was to assess risk for sinonasal IP associated with prior exposure to suspected occupational risk factors for sinonasal malignancies. METHODS: Between 1996 and 2007, data on incident cases were collected from hospitals throughout the Piedmont region of Italy by the regional sinonasal cancer registry. A questionnaire on occupational history, completed by 127 cases and 337 hospital controls, was used to assign previous exposure to a list of 17 occupational hazards. The relationship between IP and cumulative exposure to these hazards was explored using unconditional logistic regression to statistically adjust for age, sex, area of residence, smoking and co-exposures. RESULTS: The risk of IP was significantly increased for ever exposure to welding fumes (OR 2.14) and organic solvents (OR 2.11) after controlling for potential confounders. For organic solvents only, a significant association with continuous cumulative exposure and a significant trend in risk across ordered cumulative exposure categories was found. CONCLUSIONS: The present study revealed a significant association and a significant dose-response relationship between occupational exposure to organic solvents and IP. The lack of a dose-response relationship for welding fumes suggests that the observed association with ever exposure should be interpreted with caution.

[Sino-nasal inverted papillomas and occupational etiology]. / Papillomi invertiti naso-sinusali ed eziologia occupazionale.

The sino-nasal inverted papilloma is a rare benign tumour with certain aggressive features because of frequent relapses and the high probability of malignant degeneration. For these reasons, several studies have been made to evaluate the efficacy of the different courses of treatment, but only afew studies have been carried out to establish the etiology of this tumour, which is still uncertain. Although it is believed that viral infection, chronic inflammation and cigarette smoking can play an important etiological role, it has recently been suggested that occupational risk factors, such as those involved in malignant epithelial sino-nasal cancer (SNC), can also be involved in causing sino-nasal inverted papilloma. A group of 70 patients was examined who have been diagnosed with inverted papilloma from 1991 to 2003; the occupational history, collected via the standardized questionnaire, showed that risk factors like wood and leather dusts, chromium and nickel vapours or fumes and formaldehyde were associated with only 5% of all cases. This proportion is much lower than that established for SNC in several epidemiological studies. Although occupational environmental pollution can be a source of chronic sino-nasal mucosa irritation, on the basis of our results we believe that a causal relationship between exposure to occupational risk factors and inverted papilloma is not likely, differently from the suggestions made in other studies. Consequently, an epidemiological surveillance of inverted papilloma as a "sentinel" tumour, as has been proposed in Italy for SNC, is not considered necessary. Among the possible non-occupational risk factors we observed that 75% of the male patients were smokers and 40% of all patients suffered from chronic sinusitis and sino-nasal polyps. Lastly, among the 70 cases of inverted papilloma, we observed 5 with malignant degeneration.