science

National Lung Screening Trial

National Lung Screening Trial is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand National Lung Screening Trial rather than just read about it. In short: The National Lung Screening Trial was a United States-based clinical trial which recruited research participants between 2002 and 2004. It was sponsored by the National Cancer Institute and conducted by the American College of Radiology Imaging Network and the Lung Screening Study Group.

Key takeaways

National Lung Screening Trial belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect National Lung Screening Trial to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of National Lung Screening Trial from memory before moving on to harder problems.

Reference excerpt

The National Lung Screening Trial was a United States-based clinical trial which recruited research participants between 2002 and 2004. It was sponsored by the National Cancer Institute and conducted by the American College of Radiology Imaging Network and the Lung Screening Study Group. The major objective of the trial was to compare the efficacy of low-dose helical computed tomography (CT screening) and standard chest X-ray as methods of lung cancer screening to reduce deaths from lung cancer. The primary study ended in 2010, and the initial findings were published in November 2010, with the main results published in 2011 in the New England Journal of Medicine. The trial led to a recommendation in the United States in 2013 that CT screening be used on people at high risk for developing lung cancer in an effort to detect the cancer earlier and reduce mortality. Current United States Preventive Services Task Force recommendations as of 2021 are "annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years" (Grade B).

Study design The study looked at 53,454 current or former heavy smokers from 33 medical centers in the US. The ages of the patients in the trial varied from 55 to 74. When their initial findings were published in the New England Journal of Medicine, the researchers reported that low-dose CT scanning was associated with a 20% decrease in deaths from lung cancer, and that this effect was visible in both current smokers and former smokers. More recent research based on this trial, published in JAMA Internal Medicine, has found that low-dose computed tomography detects many false positives—in the study, 18% of total detections were considered to be an overdiagnosis, i.e. the cancer would never have threatened the life of the patient. The National Cancer Institute funded a $300m study, the National Lung Screening Trial (NLST), which began in 2002, to compare the effectiveness of CT scan screening versus X-ray screening. This study, too, raised concern in the media over potential conflicts of interest related to the tobacco company, although this time on the contra-CT scan side: on October 8, 2007, the Wall Street Journal reported that at least two lead investigators of the study had conflicts of interest arising from their serving as paid, expert defense witnesses for the tobacco industry – one of them had given testimony asserting that promoting CT screening was "reckless or irresponsible" until it was shown by randomized controlled trials to reduce lung cancer mortality; another had provided an expert report warning that CT screening, because of its potential to identify cancers that would never cause symptoms or death (overdiagnosis), "may do more harm than good."

Results Deaths in either group were then logged for up to five years. As of October 2010, 354 people in the CT scan group had died from lung cancer, versus 442 people in the X-ray group; in other words, deaths in the CT scan group of patients were 20.3% lower than in the X-ray group. The study's review board concluded that this difference was statistically significant and recommended terminating the study. The director of the National Cancer Institute's director, Harold Varmus, said that early analysis results appeared to indicate that CT scans detected more lung cancers, at an earlier and more treatable stage, and that CT scans could therefore reduce the number of deaths in patients at high risk of lung cancer. Moreover, the medical complications resulting directly or indirectly from CT screening were minimal in those who were not diagnosed with lung cancer. [5]

References

Further reading The trial's main result is here:

Aberle DR, Adams AM, Berg CD, Black WC, Clapp JD, Fagerstrom RM, Gareen IF, Gatsonis C, Marcus PM, Sicks JD (2011). "Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening". New England Journal of Medicine. 365 (5): 395–409. doi:10.1056/NEJMoa1102873. ISSN 0028-4793. PMC 4356534. PMID 21714641.

External links entry at ClinicalTrials.gov National Lung Screening Trial: Questions and Answers at the National Cancer Institute

Worked examples

Example 1 — a first encounter with National Lung Screening Trial

Start with the simplest possible case. Write down what National Lung Screening Trial claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to National Lung Screening Trial before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about National Lung Screening Trial ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of National Lung Screening Trial

In research: National Lung Screening Trial appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses National Lung Screening Trial in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: National Lung Screening Trial is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2000s in the United States, 2002 beginnings, 2010 endings, so understanding it makes those chapters shorter.
In everyday life: Look for National Lung Screening Trial outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study National Lung Screening Trial in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what National Lung Screening Trial means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain National Lung Screening Trial out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is National Lung Screening Trial in simple terms?

Why does National Lung Screening Trial matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study National Lung Screening Trial?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on National Lung Screening Trial.