Publications
Partners
More research is suggesting that heavy smokers may benefit from screening for lung cancer.
In the latest study, smokers screened with CT scans had a significantly lower 10-year mortality rate compared to unscreened smokers.
The results are in keeping with those of a much larger study published last month, which showed that CT scans reduced the death rate among 53,000 current and former heavy smokers by 20% compared to screening with chest x-rays.
The newer study, published online in Lung Cancer, involved roughly 8,000 current and former smokers. The researchers estimated that those who received up to two CT scans would reduce their risk of death by 36% to 64% compared to those who went unscreened.
Still many issues to be dealt with
But while the data are consistent with earlier studies, there are still many issues to resolve regarding lung cancer screening, said Dr Bruce Johnson of the Dana Farber Cancer Institute.
For one, it's not clear how often to screen people, and when to start. It is not clear when or how guidelines for lung cancer screening could be drawn up, and until they are, insurers including government programs such as Medicare are unlikely to pay the average $300 (about R2,000) cost of a scan.
Furthermore, another study showed that 21% of initial lung CT scans yield false positive results. These lead to needless invasive follow-up procedures and radiation exposure, as well as stress and anxiety.
In recent years, CT scans in particular have been promoted by some hospitals and advocacy groups for lung cancer screening, even though studies had not yet shown definitively whether CT screening saves lives.
In 2006, Dr Claudia Henschke, currently based at Mount Sinai School of Medicine and Arizona State University, US, caused a stir when she reported that 80% of lung-cancer deaths could be prevented through widespread use of spiral CT.
Her ideas were controversial to start with, especially when it became known that her work was funded by a tobacco company.
Henschke's study
In the current study, funded in part by manufacturers of CT scanners (along with government and other sources), Henschke and her colleagues compared outcomes in three groups. Nearly 8,000 smokers and former smokers had CT screening; and two sets of people with smoking histories who were not scanned.
A total of 64 people died in the screened population, the authors report, but compared to matched controls in one of the unscreened populations, the mortality risk was 36% lower with screening.
Applying the same methods to the other unscreened population, the authors estimated that screening was associated with a 64% lower risk of death.
Overall, research is suggesting that CT scans of people at risk of lung cancer might make a dent in cancer mortality, and it's possible that more frequent screening might make an even bigger dent, said Dr James Hanley of McGill University.
"If screening is going to work," he said, "you've got to keep at it." - (Reuters Health/Alison McCook, December 2010)
Read more:
