Quinn Michael
Oncology/Dysplasia Unit, Royal Women's Hospital, Melbourne, Australia.
Yonsei Med J. 2002 Dec;43(6):717-21. doi: 10.3349/ymj.2002.43.6.717.
It is often difficult to conclude that improvements in survival with time are due to a screening programme alone. Although a reduction in the death rate from a given cancer may reflect the benefits of early detection or improved treatment, the benefits may also result from lead time bias and over-diagnosis, the former resulting in longer survival of screen-identified cancers because the time before the cancer would have been clinically diagnosed is included in calculations. Furthermore, recent reviews on randomised clinical trials of cancer screening have provided strong evidence that misclassifications in causes of death have been a major problem, leading to an over-estimation of the effectiveness (or alternatively an under-estimation of potential harm) of screening.
通常很难断定随时间推移生存率的提高仅仅是由于筛查计划。虽然特定癌症死亡率的降低可能反映了早期检测或治疗改善的益处，但这些益处也可能源于领先时间偏倚和过度诊断，前者导致筛查发现的癌症生存期更长，因为计算中包含了癌症在临床上本应被诊断出来之前的时间。此外，最近对癌症筛查随机临床试验的综述提供了有力证据，表明死亡原因的错误分类一直是一个主要问题，导致对筛查有效性的高估（或者对潜在危害的低估）。
