CT Screening Finds Lung Cancers Early
85% of Cancers Found in Study Were More Survivable Stage 1 Type
Oct. 25, 2006 - More than 90% of lung cancer patients end up dying of their disease; now a potentially landmark study suggests early screening could save most of them.
In the international study, routine screening using spiral computed tomography (CT) imaging resulted in the detection of lung cancercancer at its earliest and most treatable stage in 85% of cancers found.
The estimated 10-year survival rate for patients with these stage I cancers was 88%.
That compares with a typical five-year survival rate of around 5% for patients with advanced, stage IV lung cancer.
"Lung cancer is highly curable if we find it early enough," lead researcher Claudia Henschke, MD, PhD, tells WebMD. "We believe this study provides compelling evidence that CT screening for lung cancer offers new hope for millions of people at risk for this disease and could dramatically reverse lung cancer death rates."
More than 31,500 people at high risk for lung cancer took part in the International Early Lung Cancer Action Project (I-ELCAP), carried out at 38 centers in seven countries.
A total of 484 lung cancers were found in this high-risk group, which included people with a history of cigarette smoking, exposure to secondhand smoke, or exposure to occupational hazards such as asbestos or radon.
The study is published in the Oct. 26 issue of The New England Journal of Medicine.
Experts who spoke to WebMD agreed the new findings are encouraging. But they also said important questions remain about the value of CT screening as a routine test for lung cancer.
In a 2004 report, a government task force concluded there is not enough evidence to either recommend or discourage routine screening of asymptomatic people for lung cancercancer.
Henschke and colleagues from New York Presbyterian Hospital-Weill Cornell Medical Center developed the screening model used in the international study. She acknowledges that adapting the model for widespread use will not be easy.
"A multidisciplinary approach and very careful follow-up is needed to make sure you aren't missing something," Henschke says.
One of the biggest concerns about the screening procedure is its high percentage of false-positive results.
According to the National Cancer Institute (NCI), studies indicate that between a quarter to more than half of CT scans among smokers and former smokers show abnormalities, and in most cases these do not turn out to be lung cancer.
The problem is that malignant tumors and benign lesions often look the same on a CT scan, and decisions about how to proceed once a lesion is found are not clear-cut.
Potentially risky invasive procedures such as needle biopsy or even surgery are usually needed to confirm a diagnosis of lung cancer.
In the I-ELCAP study, patients with small but suspicious lesions were either tested again using a different screening method or had a repeat CT scan three months later.
When a lung infection was suspected of causing a lesion, a two-week course of antibiotics was prescribed and a repeat CT was performed a month later.
If the second image showed that the lesion or lesions had grown, a needle biopsy was usually performed.