美国癌症学会支持CT筛查肺癌

美国癌症学会(ACS)日前发布指南，支持对部分高危个体采用小剂量CT扫描进行肺癌筛查。这部指南发表在《CA: A Cancer Journal for Clinicians》在线版上(doi: 10.3322/caac.21172)。

指南编撰委员会的Richard Wender博士指出：“能够进行大规模、高质量肺癌筛查的临床医生和治疗中心，应当与年龄55~74岁、有至少30包/年吸烟史、目前仍吸烟或戒烟不足15年、身体相对健康者讨论肺癌筛查问题。”

这部指南围绕NLST(全国肺部筛查试验)中采用的合格标准提出建议。由于获益与风险之间的平衡情况尚不明确，目前不推荐对年龄更小或更大者、一生中烟草暴露时间更短者，以及肺损伤较严重而需要吸氧者进行肺癌筛查。指南作者承认，如果患者的风险接近或超过NLST合格标准中的某一方面，而不符合标准的其他方面，临床医生就需要自己酌情作出判断。

由于公立或私立保险机构很少覆盖首次小剂量CT肺癌筛查，“决定提供筛查的临床医生有责任帮助患者决定是否要自费接受初次筛查，并且帮助患者了解所需支付的金额。鉴于有充分证据表明筛查高危个体可明显降低肺癌死亡率，公立和私立医疗保险机构都应当将高危每年接受(小剂量CT)肺癌筛查的费用纳入赔付范围。”

一方面小剂量CT已被证实可显著降低肺癌死亡风险，而另一方面这项技术无法检出所有的肺癌，也无法确保足够早地检出肺癌以避免肺癌死亡。而且，假如筛查得出假阳性结果，有可能促使患者接受侵入性检查。这部指南还警告称，目前吸烟者不能将筛查视为戒烟的替代品。建议目前吸烟者进行咨询，所有符合每年筛查标准者都应仅在愿意接受每年筛查的风险和费用、年龄不足74岁的前提下作出决定。

这部指南还指出，胸部X线检查不得被用于肺癌筛查。

只要有可能，都应当由小剂量CT筛查方面的专家，以及善于评估、诊断和治疗异常肺部病变的多学科小组，将肺癌筛查作为有序项目中的一部分来加以实施。假如患者强烈希望接受筛查，应将其转至有丰富肺部CT扫描、诊断检查和肺癌手术经验的中心。否则，“肺癌筛查相关风险可能会明显高于在NLST中观察到的风险。”

指南编撰委员会的多名委员披露称与药企存在利益关系。一名承认与器械生产商有关系的委员宣称其工作与这部指南无直接关联。

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By: MARY JO DALES, Internal Medicine News Digital Network

Low-dose CT scans were endorsed for lung cancer screening in select high-risk individuals in guidelines from the American Cancer Society.

"Clinicians with access to high-volume, high-quality lung cancer screening and treatment centers should initiate a discussion about lung cancer screening with patients aged 55 years to 74 years who have at least a 30–pack-year smoking history, currently smoke, or have quit within the past 15 years, and who are in relatively good health," wrote Dr. Richard Wender and the members of the guidelines committee in an article published online in CA: A Cancer Journal for Clinicians (doi: 10.3322/caac.21172).

The recommendations are centered on the eligibility criteria used in the NLST (National Lung Screening Trial). Because of the uncertainty regarding the balance of benefits and harms, low-dose CT screening is not recommended for individuals at younger or older ages, with less lifetime exposure to tobacco smoke, and with sufficiently severe lung damage to require oxygen. The guideline writers acknowledge that clinicians will need to rely on their best judgment in cases when risk seems to approximate or exceed the NLST eligibility criteria in one category but not in another.

Since few government or private insurance programs provide coverage for the initial low-dose CT for lung cancer screening, "clinicians who decide to offer screening bear the responsibility of helping patients determine if they will have to pay for the initial test themselves and to help the patient know how much they will have to pay," according to the guideline writers. "In light of the firm evidence that screening high-risk individuals can substantially reduce death rates from lung cancer, both private and public health care insurers should expand coverage to include the cost of annual (low-dose CT) screening for lung cancer in appropriate high-risk individuals."

The "meaningful use" criteria for electronic health records under the recent HITECH (Health Information Technology for Economic and Clinical Health) Act are likely to improve identification of patients eligible for this screening as clinicians are required to determine the smoking status of more than 50% of their patients who are aged 13 years or older and to track the percentage of patients aged 10 years and older who are current smokers, according to Dr. Wender, chair of the department of family and community medicine, Jefferson Medical College, Philadelphia, and the other guideline writers.

While low-dose CT screening has been shown to substantially reduce the risk of dying of lung cancer, the technology will not detect all lung cancers or all lung cancers in early enough stages to avoid death from lung cancer. Further, a false-positive finding runs the risk of prompting an invasive procedure for incidental findings. The guidelines also warn that current smokers should not view screening as a substitute for smoking cessation. Counseling is recommended for current smokers, and all patients eligible for annual screening should make the decision only if they are willing to accept the risks and costs of annual screening until they reach age 74 years.

The guidelines also note that chest x-rays should not be used for lung cancer screening.

Wherever possible, screening should be performed as part of an organized program at an institution with expertise in low-dose CT screening and a multidisciplinary team skilled in the evaluation, diagnosis, and treatment of abnormal lung lesions. When those options are available but patients strongly wish to be screened, they should be referred to a center that performs a reasonably high volume of lung CT scans, diagnostic tests, and lung cancer surgeries. Otherwise, "the risks of cancer screening may be substantially higher than the observed risks associated with screening in the NLST, and screening is not recommended."

Multiple members of the guideline committee had financial disclosures related to drug manufacturers. The single committee member with ties to a device manufacturer declared his work was not directly related to the article.