Scientific data are often used in lawsuits to prove, or dismiss, causation by a claimed factor of a claimed disease. Recent media reports of million-dollar compensations awarded to some cancer patients who had been exposed to certain chemical substances motivated me to examine how solid the causal links really were. Here, I discuss the limitations of epidemiological research on cancer causation and highlight how new knowledge of cancer genetics makes it unrealistic to expect that cancer causation can be clearly demonstrated. I then present two exposure–cancer cases, namely talcum powder–ovarian cancer and glyphosate–non-Hodgkin lymphoma, that led to civil lawsuits decided, in the United States, in favor of the claimants. Both these cancers have several risk factors, among which the claimed exposure presents only a minor, if any, increased risk. Through these cases, I explain why the use of epidemiological data is inappropriate to define causal associations in complex diseases like cancer. I close by suggesting a fairer approach, called proportional liability, to resolving future cancer litigation cases.

科学数据经常在诉讼中用来证明或驳回所声称的疾病的声称因素的因果关系。最近的媒体报道称，一些接触过某些化学物质的癌症患者获得了数百万美元的赔偿，这促使我去研究因果关系的真实性。在这里，我讨论了流行病学研究癌症因果关系的局限性，并强调癌症遗传学的新知识如何使得期望清楚地证明癌症因果关系变得不现实。然后，我介绍了两个暴露癌症案例，即滑石粉导致卵巢癌和草甘膦导致非霍奇金淋巴瘤，这两个案例在美国引发了有利于原告的民事诉讼。这两种癌症都有多种危险因素，其中所声称的接触风险即使有，也只会轻微增加。通过这些案例，我解释了为什么使用流行病学数据来定义癌症等复杂疾病的因果关系是不合适的。最后，我建议采用一种更公平的方法，称为比例责任，来解决未来的癌症诉讼案件。