Lung Cancer Screening with CT Scan May Reduce Deaths

Screening with low-dose helical computed tomography (spiral CT) scans may reduce deaths from lung cancer among smokers. These findings were recently released by the National Cancer Institute.

CT scanning is being studied as a screening tool for lung cancer. Some studies have indicated that screening with CT may provide improved long-term survival for patients with lung cancer; however, not all studies demonstrate improved survival. Because of the uncertainty of the benefit and the potential for harm from screening, the medical community has not yet adopted CT scanning for standard screening for lung cancer.

In order for new screening methods to be adopted into routine clinical care, the measures must identify cancer early enough to improve outcomes, must be economically feasible, and must detect cancer with an acceptable degree of accuracy. As well, in order to encourage patient compliance, screening measures must not be too invasive, painful, or risky. To date no screening measures for lung cancer have been identified that provide a confirmed benefit.

Researchers with the National Lung Cancer Screening Trial, a national trial involving more than 53,000 current and former heavy smokers, evaluated the impact of screening for lung cancer using two screening methods: low-dose helical CT scans and standard chest X-ray. Participants had smoked for at least 30 pack-years (the average number of cigarettes smoked per day multiplied by the number of years the person smoked).

  • There were 20% fewer lung cancer deaths among patients who were screened with CT scan compared with those screened with chest X-ray: 354 versus 422 deaths, respectively.
  • The researchers determined that this 20% reduction in lung cancer deaths for CT-screened patients was statistically significant and therefore recommended ending the study.
  • All-cause mortality (death from any cause, including lung cancer) was also reduced (by 7%) among patients who underwent CT screening.

The researchers concluded that screening for lung cancer with low-dose CT scans may effectively detect early disease among smokers and therefore reduce deaths among this population. They add that, while this finding could potentially save thousands of lives, the best way to prevent lung cancer is to abstain from or quit smoking. As well, concerns remain about widespread use of CT screening; these include expense, radiation exposure, and the risk of false-positive results (which may lead to unnecessary medical procedures). Further analysis of these data is warranted before CT scans are added to guidelines and policy recommendations for lung cancer screening.

Reference: The National Cancer Institute. Lung cancer trial results show mortality benefit with low-dose CT. (Accessed November 5, 2010).

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