Implications of Evolving Medical Science for Proof of Lung Cancer Causation

Causal determination in cases of diseases involving multiple risk factors and long development time poses formidable challenges to judges and juries. Numerous scientific, medical and legal questions are involved. For example, is the mere presence of a factor known to be associated with elevated disease risk sufficient for a causal determination? If not, what level of exposure should be deemed sufficient, and how can that exposure be measured with adequate confidence over an extended period? In the presence of two or more factors associated with elevated disease risk, how can causation be demonstrated and apportioned among these factors, particularly when the potential effects of their interaction are unknown? With increasing knowledge of the molecular and genetic changes involved in disease development, what level of comprehension and proof is sufficient to implicate a specific risk factor in the complex causal mechanism of an individual’s disease? Lung cancer, notwithstanding its strong association with cigarette smoking, represents a group of diseases associated with both a variety of risk factors and relatively long development time. Both the published scientific literature and current clinical practice for the treatment of lung cancer, particularly lung adenocarcinoma, reflect the rapid changes that have occurred in this field over the past decade. These medical advances, in addition to promising better prognosis for some lung cancer patients, have implications for the proof of lung cancer causation in litigation in which plaintiffs contend that tobacco smoke exposure caused their disease. This is particularly true in cases arising in many European countries and other jurisdictions in which little or no histological or cytological information has been produced by plaintiffs. This paper examines the rapidly evolving science underpinning lung cancer diagnosis and treatment and its forensic implications. [Beitr. Tabakforsch. Int. 26 (2015) 298-311]