I-ELCAP 研究颇受争议

hxq2007

夸大早期肺癌CT检查需求：I-ELCAP 研究颇受争议
Overstating the Case for Lung Cancer Screening: More Criticism of the I-ELCAP Study

November 27, 2007 — Further criticism has been directed at the International Early Lung Cancer Action Program (I-ELCAP), which led to calls for lung cancer screening with spiral computed tomography (CT). That study overstated the evidence, according to a special article in the November 26 issue of Archives of Internal Medicine.

Such screening would be a mistake, because neither this study nor any other published data constitute sufficient evidence for its benefit, the special article concluded. The only way to know the balance of benefit and harm is a randomized trial, and 2 are currently underway. \"We eagerly await the results, although they are at least 3 years away,\" said the authors, headed by Gilbert Welch, MD, MPH, of Dartmouth Medical School, in Hanover, New Hampshire.

This is not the first time that the I-ECLAP study has come under criticism; other experts have also emphasized the need to wait for randomized trials, as previously reported by Medscape Oncology. The special article reiterates some of the previous criticism, but goes into considerable detail about essential elements that the authors believe are missing from the publication.

Big Splash in the Lay Media

When I-ELCAP was published last year (N Engl J Med 2006; 355(17):1763-1771), the study made a big splash in the lay media — it was picked up by 4 of the 5 major television networks and 7 of the 10 highest-circulation newspapers in the United States. \"It was tempting to conclude that the I-ELCAP investigation on spiral CT had made a strong case for initiating lung screening now,\" Dr. Welch and colleagues commented.

The study has also been cited as compelling evidence for screening by the patient advocacy group Lung Cancer Alliance. That group is currently promoting an advertising campaign featuring sports celebrities encouraging the lay public \"to make the right call and get screened,\" they added.

However, the I-ELCAP study cannot be used to recommend lung cancer screening, said Dr. Welch and colleagues, because there are 4 essential elements missing from the published study: a control group, an unbiased outcome measure, information on what is already known about this topic from previous studies, and the harms of screening.

In retrospect, many of the problems with the way this study was publicized could have been addressed with 3 editorial alterations to the abstract, Dr. Welch and colleagues suggested. First, it should have clearly stated that the study design was a case series. Second, a comment such as \"Limitations: Increased survival may not translate into reduced mortality\" could have helped to temper the inferences made. Third, the conclusion \"should have been expanded beyond the single sentence that was published: 'Conclusion: Annual spiral CT screening can detect lung cancer that is curable.' Although technically true, it failed to highlight 2 fundamental unresolved questions: Would screening 'cure' the 160 000 cancers that patients die from now? Or would it 'cure' cancer that never needed to be cured?\"

To be fair, assessing the value of screening is challenging, and the challenges apply to screening for other cancers as well as lung cancer, Dr. Welch and colleagues write. \"But the burden of proof must be on the proponents of screening.\"