Begg C B, Zhang Z F, Sun M, Herr H W, Schantz S P
Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Am J Epidemiol. 1995 Sep 15;142(6):653-65. doi: 10.1093/oxfordjournals.aje.a117689.
The Surveillance, Epidemiology, and End Results (SEER) database is used to estimate the standardized incidence ratios (SIRs) of second primaries for all pairs of smoking-related cancers and to interpret the results in the context of our knowledge of the known effects of smoking on the incidence of each of the individual cancers. In evaluating the simultaneous incidence of two cancers, one must recognize the inherent duality of the two relevant SIRs linking the two cancers (e.g., A and B), namely, the SIRs of A following B and B following A. Under fairly general assumptions, the two SIRs are seen to be equal, and departures from equality suggest changes in risk status or the introduction of new risk factors after the incidence of the first primary. Based on these observations, a methodological strategy is developed. The data reveal several clear patterns. First, short-term incidence is uniformly much greater than long-term incidence. Second, the SIRs are consistently much higher for women than for men, for every pair of cancers studied. Third, the magnitudes of the SIRs are generally high and often substantially higher than would be expected on the basis of the known risks of smoking. Exceptionally high SIRs are observed between kidney and bladder cancer and between head and neck and esophageal cancer. Various influences may affect these high observed SIRs, including artifactual influences such as diagnostic, surveillance, and misclassification biases, and the effect of different exposure prevalences on subsequent SIRs, which may to some extent explain the strong sex differences. However, these artifacts do not appear to explain the magnitude of the observed SIRs, especially the very strong associations between kidney and bladder cancer and between head and neck and esophageal cancer. It seems likely that other factors play a role, including, possibly, host susceptibility factors or additional common risk factors other than smoking. Although multiple primary cancers are rare, they represent an especially fruitful population for detailed epidemiologic study.
监测、流行病学和最终结果（SEER）数据库用于估计所有与吸烟相关癌症对的第二原发癌的标准化发病比（SIR），并根据我们对吸烟对每种个体癌症发病率已知影响的了解来解释结果。在评估两种癌症的同时发病率时，必须认识到连接这两种癌症（例如A和B）的两个相关SIR的内在双重性，即B发生后A的SIR和A发生后B的SIR。在相当一般的假设下，这两个SIR被认为是相等的，而偏离相等则表明在第一个原发癌发病后风险状态发生了变化或引入了新的风险因素。基于这些观察结果，制定了一种方法策略。数据揭示了几个明显的模式。首先，短期发病率始终远高于长期发病率。其次，在所研究的每对癌症中，女性的SIR始终远高于男性。第三，SIR的幅度通常很高，而且往往大大高于基于已知吸烟风险所预期的水平。在肾癌和膀胱癌之间以及头颈癌和食管癌之间观察到异常高的SIR。各种影响可能会影响这些观察到的高SIR，包括诊断、监测和错误分类偏差等人为影响，以及不同暴露患病率对后续SIR的影响，这在一定程度上可能解释了强烈的性别差异。然而，这些人为因素似乎并不能解释观察到的SIR的幅度，特别是肾癌和膀胱癌之间以及头颈癌和食管癌之间非常强的关联。似乎其他因素也起了作用，包括可能的宿主易感性因素或除吸烟外的其他共同风险因素。虽然多重原发性癌症很少见，但它们是详细流行病学研究的一个特别有成果的人群。
