Muir C S, Fraumeni J F, Doll R
Information and Statistics Division, Cancer Registration in Scotland, Edinburgh.
Cancer Surv. 1994;19-20:5-21.
The requirements for valid comparison over time of cancer incidence and mortality are given in the opening paragraphs of this chapter. Among the more important of these is comparability between ICD revisions. Yet those entrusted with the decennial revisions of the International Statistical Classification of Diseases, Injuries and Causes of Death (ICD) have to try to reconcile several frequently contradictory demands. These include (a) meeting the needs of an ever widening number of users (hence, the change in title for the 10th revision to International Statistical Classification of Diseases and Related Health Problems); (b) incorporation of advances in the understanding of the biology of disease while avoiding ephemeral notions and classifications; and (c) the preservation of the continuity of time series. These desiderata have not always been met: some of the resulting problems have been discussed above. Despite the foregoing, the comparison of time trends in cancer incidence and mortality is a valid and useful exercise particularly when the investigator systematically considers the possible sources of bias and error. A low rate, if based on over a million person-years of observation, is, if underregistration can be ruled out, likely to reflect reality. Nevertheless, the smaller the number of cases and the greater the standard error of the rate, notably for the less frequent sites and the rarer histological types, the more attention needs to be paid to questions of possible artefact. Should the data for a given area or time period appear out of line with what might be expected, it may be worthwhile to check with the registry in question to see whether the trend could be explained on the basis of local circumstances, custom or practice. A formal review of the evidence for an apparent change over time, drawing on the experience of epidemiologists, pathologists and clinicians, as for example in non-Hodgkin's lymphoma, can be very useful (Levine and Hoover, 1992). Hitherto, much of the study of time trends of both incidence and mortality, notably those comparing international data, has been based on data published at the level of three digits in the ICD. Although such analyses will continue to be illuminating, future work is likely to give much greater emphasis to subsite and histological type, information that is difficult to publish routinely.(ABSTRACT TRUNCATED AT 400 WORDS)
本章开头段落阐述了对癌症发病率和死亡率进行有效时间比较的要求。其中较为重要的一点是国际疾病分类修订版之间的可比性。然而，负责《国际疾病、损伤和死因统计分类》（ICD）十年一次修订的人员必须努力协调几个经常相互矛盾的要求。这些要求包括：（a）满足越来越多用户的需求（因此，第十次修订版的标题改为《国际疾病及相关健康问题统计分类》）；（b）纳入对疾病生物学认识的进展，同时避免短暂的概念和分类；（c）保持时间序列的连续性。这些愿望并非总能实现：上述已经讨论了一些由此产生的问题。尽管如此，癌症发病率和死亡率时间趋势的比较是一项有效且有用的工作，特别是当研究者系统地考虑可能的偏差和误差来源时。如果基于超过一百万人年的观察得出低发病率，且能排除漏报情况，那么该发病率很可能反映实际情况。然而，病例数越少且发病率的标准误差越大，尤其是对于发病率较低的部位和罕见的组织学类型，就越需要关注可能的人为因素问题。如果给定地区或时间段的数据与预期不符，不妨向相关登记处核实，看该趋势是否能基于当地情况、习俗或惯例得到解释。借鉴流行病学家、病理学家和临床医生的经验，对随时间推移出现的明显变化的证据进行正式审查，例如在非霍奇金淋巴瘤方面，可能会非常有用（莱文和胡佛，1992年）。迄今为止，发病率和死亡率时间趋势的许多研究，尤其是比较国际数据的研究，大多基于ICD三位数层面公布的数据。尽管此类分析仍将具有启发性，但未来的工作可能会更加强调亚部位和组织学类型，而这些信息很难常规发布。（摘要截选至400字）
