Role of organochlorine compounds in the etiology of pancreatic cancer: a proposal to develop methodological standards.
Studies on the possible role of organochlorine compounds in the etiology of pancreatic and other cancers face a set of methodologic and logistic issues that stem from the lipophilic nature of most organochlorines, and from the fact that tumor-induced lipid mobilization, weight loss, and metabolic changes can be profound before diagnosis. The question thus arises: do the xenobiotic concentrations in blood and adipose tissue result, in part, from such pathophysiologic changes? To assess and control potential selection and information biases, a flexible framework is warranted. It could be based on indicators such as time elapsed between the first symptom of cancer and blood or fat sample extraction; signs, symptoms and clinical status at the time of extraction; cholesterol and triglycerides levels; other laboratory findings; tumor stage at diagnosis; diagnostic procedures; treatment type and timing; clinical complications; and survival. Before adopting qualitative criteria and quantitative standards, their impact upon causal estimators should be assessed empirically.
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Grup de Recerca en Epidemiologia Clínica i Molecular del Càncer, Institut Municipal d'Investigació Mèdica, Universitat Autònoma de Barcelona, Spain.
D003634:DDT / Q000009:adverse effects; D004812:Epidemiologic Methods; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000009:adverse effects* / Q000097:blood; D050356:Lipid Metabolism; D010190:Pancreatic Neoplasms / Q000139:chemically induced*; D011078:Polychlorinated Biphenyls / Q000009:adverse effects
D006843:Hydrocarbons, Chlorinated; D003634:DDT; D011078:Polychlorinated Biphenyls