NCI Launch New Screening Trial

The National Cancer Institute in the United States has launched a $200 million multicentre randomised controlled trial comparing the effectiveness of spiral computed tomography (CT) with chest X-rays (CXR) to reduce lung-cancer death.

One of the largest studies ever done on lung-cancer screening, the National Lung Screening Trial (NLST) aims to enroll 50 000 current and former smokers at 30 locations around the US.

“The NLST will allow us to see if spiral CT is better than chest X-ray in reducing deaths from lung cancer, as many suspect”, says John Gohagan, NCI Project Officer and head of the Early Detection Research Group.

A current NCI-sponsored trial comparing the effectiveness of CXR screening versus no screening in 150 000 participants, will provide definitive answers about CXR screening that have been otherwise unresolved in other smaller trials.

“The trial is powered to find as small a difference in mortality as 20% between the two screening methods”, Gohagen said. “The data from both trials will tell us whether spiral CT or chest X-ray should be used for lung cancer screening, and whether or not the effectiveness of spiral CT can justify using such a high cost technology.”

Denise Aberle, co-principal investigator and head of Thoracic Imaging at the David Geffen School of Medicine commented on the technology identifying cancers. “A small lung-cancer is not necessarily an early cancer. Small cancers may be more aggressive than larger ones, because of genetic and biological factors unrelated to their size at the time of diagnosis” and that “CT is more sensitive, and as such, will result in more false positive screens. This may expose more individuals to unnecessary diagnostic tests and the potential of medical, emotional, and economic risks.”

Participants in the trial will be randomly assigned to two groups – chest x-ray or spiral CT. Both groups will receive yearly screening for three years. Participants will be followed until the conclusion of the trial. The completion date is 2009.

The primary objective of the study is the difference in lung-cancer mortality between the two screening tests, however the investigators will also study the effect of screening, smoking, health-related behaviour, quality of life, medical resource utilisation, and costs.

(Source: The Lancet)