New insights into the mortality risk from nasopharyngeal cancer in the national cancer institute formaldehyde worker cohort study

Abstract Background Indications were found that a diagnostic bias could have contributed to the National Cancer Institute’s (NCI) suggestion of a persistent increased mortality risk for nasopharyngeal cancer (NPC). Methods NCI provided the cohort data updated through 2004. We computed local county rate-based standardized mortality ratios (SMRs) for NPC and all other entities of the pharynx for two time periods. Moreover, SMRs were calculated for pharyngeal cancer in relation to study site by cumulative exposure to formaldehyde (FA). Results Overall, our results corroborate the indications of a diagnostic bias by strong but contrary temporal trends for NPC and pharynx, not specified. Moreover, it was shown that mortality risks were increased in the Wallingford cohort for all pharyngeal cancer combined and for pharyngeal cancer excluding NPC. In contrast, no increased risks for these categories were found in the nine other study sites combined. Conclusions Our re-analysis provided little or no evidence to support NCI’s suggestion of a persistent association between FA exposure and mortality from NPC

Solvent exposure and malignant lymphoma: a population-based case-control study in Germany.

AimsTo analyze the relationship between exposure to chlorinated and aromatic organic solvents and malignant lymphoma in a multi-centre, population-based case-control study.MethodsMale and female patients with malignant lymphoma (n = 710) between 18 and 80 years of age were prospectively recruited in six study regions in Germany (Ludwigshafen/Upper Palatinate, Heidelberg/Rhine-Neckar-County, Würzburg/Lower Frankonia, Hamburg, Bielefeld/Gütersloh, and Munich). For each newly recruited lymphoma case, a gender, region and age-matched (+/- 1 year of birth) population control was drawn from the population registers. In a structured personal interview, we elicited a complete occupational history, including every occupational period that lasted at least one year. On the basis of job task-specific supplementary questionnaires, a trained occupational physician assessed the exposure to chlorinated hydrocarbons (trichloroethylene, tetrachloroethylene, dichloromethane, carbon tetrachloride) and aromatic hydrocarbons (benzene, toluene, xylene, styrene). Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression analysis, adjusted for smoking (in pack years) and alcohol consumption. To increase the statistical power, patients with specific lymphoma subentities were additionally compared with the entire control group using unconditional logistic regression analysis.ResultsWe observed a statistically significant association between high exposure to chlorinated hydrocarbons and malignant lymphoma (Odds ratio = 2.1; 95% confidence interval 1.1-4.3). In the analysis of lymphoma subentities, a pronounced risk elevation was found for follicular lymphoma and marginal zone lymphoma. When specific substances were considered, the association between trichloroethylene and malignant lymphoma was of borderline statistical significance. Aromatic hydrocarbons were not significantly associated with the lymphoma diagnosis.ConclusionIn accordance with the literature, this data point to a potential etiologic role of chlorinated hydrocarbons (particularly trichloroethylene) and malignant lymphoma. Chlorinated hydrocarbons might affect specific lymphoma subentities differentially. Our study does not support a strong association between aromatic hydrocarbons (benzene, toluene, xylene, or styrene) and the diagnosis of a malignant lymphoma