Reich J M
Thoracic Oncology Program, Earl A Chiles Research Institute, Portland Providence Medical Center, 7400 SW Barnes Rd, A622, Portland, OR 97225, USA.
Thorax. 2008 Apr;63(4):377-83. doi: 10.1136/thx.2007.079673.
The magnitude of overdiagnosis is a critical and unresolved issue in lung cancer (LC) screening:(1) its contribution to the increase in survival constitutes specious evidence of benefit;(2) overdiagnosed individuals who undergo resection will experience a reduction in life expectancy, partially or completely offsetting the benefit received by others in whom earlier intervention proves curative.
Critical analysis of studies in opposition and support of the view that LC screening imposes a substantial burden of overdiagnosis.
Approximately 25%, possibly more, of radiographically (chest x ray) diagnosed LC appears to be overdiagnosed. Based on the observed tumour volume doubling time of low dose CT identified small malignant pulmonary nodules, CT will markedly augment lead time, increasing exposure to competing lethal morbidities, thereby increasing overdiagnosis.
To reduce all-cause mortality, CT screening will need to reduce LC mortality by an amount that exceeds the increase in mortality attributable to surgery and loss of pulmonary reserve in persons who are overdiagnosed or pathologically understaged (ie, with occult micrometastases). Presently, there is no evidence that CT screening will achieve any reduction in LC mortality.
过度诊断的程度是肺癌（LC）筛查中一个关键且未解决的问题：（1）其对生存率提高的贡献构成了似是而非的获益证据；（2）接受切除的过度诊断个体的预期寿命将会缩短，部分或完全抵消了那些早期干预被证明可治愈的个体所获得的益处。
对反对和支持LC筛查带来大量过度诊断负担这一观点的研究进行批判性分析。
通过影像学（胸部X线）诊断的LC中，约25%甚至可能更多似乎是过度诊断。基于低剂量CT发现的小的恶性肺结节的观察到的肿瘤体积倍增时间，CT将显著延长领先时间，增加对竞争性致命疾病的暴露，从而增加过度诊断。
为降低全因死亡率，CT筛查需要降低LC死亡率的幅度超过因手术导致的死亡率增加以及过度诊断或病理分期过低（即存在隐匿性微转移）的个体肺储备丧失导致的死亡率增加。目前，没有证据表明CT筛查会降低LC死亡率。
