New research has shown that early screening with CT scans could significantly improve the survival rates from lung cancer.
Lung cancer is the most commonly diagnosed cancer and over 3 million people worldwide have the disease; there are 1.2 million new cases each year, the majority in developed countries.
It is the leading cancer killer in both men and women in the United States and an estimated 162,460 people will die from the disease in 2006.
In the UK 40,000 people die from lung cancer every year.
Tobacco is the main cause of lung cancer and 90 percent of lung cancer cases are caused by smoking.
Other causes include exposure to second-hand smoke, radon and asbestos and air pollution.
More men than women contract lung cancer and only 2 percent of victims survive for more than 5 years.
Six out of every 10 people with lung cancer die within 1 year of being diagnosed with the disease, and between 7 and 8 will die within 2 years.
As a rule by the time symptoms appear the disease has progressed to the stage where it is too advanced to treat, hence the poor survival rates.
This latest study by researchers in the U.S. used CT screening to examine 31,657 people who were at risk for lung cancer but did not have any symptoms.
They discovered 484 lung tumors, 412 of which were Stage I, meaning they were small and had not spread.
Of this group eight declined treatment and all died within five years, while 302 with early lung cancer sought immediate surgical treatment.
Dr. Claudia Henschke, who led the study estimates that 92 per cent of participants who were in the earliest stage of lung cancer and who had surgery within one month of diagnosis, will survive for 10 years.
Dr. Henschke of the New York-Presbyterian Hospital/Weill Cornell Medical Center, says the results provide compelling evidence that CT screening for lung cancer could offer new hope for millions of people at risk for lung cancer and could dramatically reverse lung cancer death rates.
Henschke and a team of researchers found in 1999 that a type of X-ray called spiral CT scanning could detect 85 percent of small lung tumors while they could still be surgically removed.
The researchers say that early screening with CT scans helped diagnose almost 500 people with the disease, which would not have been detected until much later.
The study has however invoked debate and criticism and some say the study does not prove that finding the cancers early saves lives and as the study did not compare participants who got scans to those who did not, it cannot conclusively show whether screening saves more lives than doing nothing.
They also argue that regular CT scans are costly and often create more false alarms than cancer diagnoses.
A suspicious lesion on an x-ray must be biopsied, or cut into, to assess whether it is actually cancer, and with lungs this carries the risk of a collapsed lung or other complications.
Three larger trials, with a total of 100,000 patients, are underway in the U.S. and Europe which will hopefully provide a clearer picture, but the results are not expected for at least five years.