JAMA：低剂量CT筛查可使肺癌高危人群受益

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JAMA：低剂量CT筛查可使肺癌高危人群受益
2012-06-19
肺癌是致死率最高的肿瘤疾病。大部分肺癌患者直到晚期才得以确诊，这导致了这些患者5年生存率非常低。筛检也许可以降低肺癌死亡率。为了对低剂量计算机断层扫描术(LDCT)筛检肺癌的利弊进行系统评估，多个学会合作（包括美国癌症协会，美国胸内科医师学会，美国临床肿瘤学学会，国家综合肿瘤网）创立了一项旨在发展基于证据的临床实践指南的基金。他们的研究显示低剂量计算机断层扫描术可能会使处于较高风险的肺癌潜在患者受益，但仍存在不确定性。相关论文发表于国际权威杂志JAMA2012年最新一期在线版，通讯作者为Memorial Sloan-Kettering肿瘤中心的Peter B. Bach博士。

这一研究的数据来源于MEDLINE (Ovid:1996年1月至2012年4月)，EMBASE (Ovid:1996年1月至2012年4月)，以及Cochrane图书馆（2012年4月）。研究纳入了符合标准的关于LDCT筛选的591篇经鉴定或评审的引文，8篇随机试验和13篇队列研究。试验首要终点观察指标为肺癌死亡率及全因素死亡率，次要终点观察指标包括结节检出率，侵袭进展，随访检查结果，以及烟草戒断率。试验对基于个体和总体研究的证据进行关键性评估，从评述中析取的数据差异达到共识后方被采用。

研究结果表明，有3例随机研究为LDCT筛检对肺癌死亡率造成的影响提供了证据，其中国家肺筛检试验研究信息量最大，它纳入了53 454 例受试者，筛检结果显示肺癌死亡数目显著性减少（LDCT组和对照组总体死亡数目及肺癌特异性死亡数分别为356 vs 443和274 vs 309每100 000人年；相对风险值，0.80；95% CI, 0.73-0.93; 绝对风险下降百分比, 0.33%; P = .004）。另外两项较小型的研究没有显示出如此大的受益。对于LDCT的潜在弊端，综合所有试验及队列，每轮大约有20%筛检显示阳性的个人需要某种程度的随访，大约1%的个人被确诊为肺癌。这一发现以及良性病变患者的随访调查及活组织检查的频度，手术率等均具有明显的异质性特征。良性状况下主要的并发症很少。

研究人员由此得出结论，低剂量计算机断层扫描术可能会使处于较高风险的肺癌潜在患者受益，但对于筛检的弊端及结果的普遍性尚存在不确定性。

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Benefits and harms of CT screening for lung cancer: a systematic review.
JAMA 2012;30722:2418-29

Bach PB Mirkin JN Oliver TK Azzoli CG Berry DA Brawley OW Byers T Colditz GA Gould MK Jett JR Sabichi AL Smith-Bindman R Wood DE Qaseem A Detterbeck FC

Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.

Abstract
Lung cancer is the leading cause of cancer death. Most patients are diagnosed with advanced disease, resulting in a very low 5-year survival. Screening may reduce the risk of death from lung cancer. To conduct a systematic review of the evidence regarding the benefits and harms of lung cancer screening using low-dose computed tomography (LDCT). A multisociety collaborative initiative (involving the American Cancer Society, American College of Chest Physicians, American Society of Clinical Oncology, and National Comprehensive Cancer Network) was undertaken to create the foundation for development of an evidence-based clinical guideline. MEDLINE (Ovid: January 1996 to April 2012), EMBASE (Ovid: January 1996 to April 2012), and the Cochrane Library (April 2012). Of 591 citations identified and reviewed, 8 randomized trials and 13 cohort studies of LDCT screening met criteria for inclusion. Primary outcomes were lung cancer mortality and all-cause mortality, and secondary outcomes included nodule detection, invasive procedures, follow-up tests, and smoking cessation. Critical appraisal using predefined criteria was conducted on individual studies and the overall body of evidence. Differences in data extracted by reviewers were adjudicated by consensus. Three randomized studies provided evidence on the effect of LDCT screening on lung cancer mortality, of which the National Lung Screening Trial was the most informative, demonstrating that among 53,454 participants enrolled, screening resulted in significantly fewer lung cancer deaths (356 vs 443 deaths; lung cancer−specific mortality, 274 vs 309 events per 100,000 person-years for LDCT and control groups, respectively; relative risk, 0.80; 95% CI, 0.73-0.93; absolute risk reduction, 0.33%; P = .004). The other 2 smaller studies showed no such benefit. In terms of potential harms of LDCT screening, across all trials and cohorts, approximately 20% of individuals in each round of screening had positive results requiring some degree of follow-up, while approximately 1% had lung cancer. There was marked heterogeneity in this finding and in the frequency of follow-up investigations, biopsies, and percentage of surgical procedures performed in patients with benign lesions. Major complications in those with benign conditions were rare. Low-dose computed tomography screening may benefit individuals at an increased risk for lung cancer, but uncertainty exists about the potential harms of screening and the generalizability of results.