Computerized chest scans that screen smokers for lung cancer can save lives, similar to the way in which mammograms are used to scan women for breast cancer, according to a recent US study.
The study found that people in whom lung tumors were detected early by CT scans and removed had an estimated 10-year survival rate of 92% which is comparatively better than the roughly 70% who typically survive, and a lot better than the dismal 5% who survive that long after the disease has spread beyond the lungs.
"It gives us greater confidence that screening may offer advantages in saving lives from lung cancer," said Dr Robert Smith, director of screening at the American Cancer Society, which, in addition to other groups funded the study.
Lung cancer has been found to be the world's top cancer killer. Around one million people worldwide will be diagnosed with it this year with most of them doomed to die, mainly because the disease is found too late for treatment to do much good. In the 1970s studies showed that screening smokers with regular X-rays did not improve lung cancer survival. However this changed with the development of CT scans in the 1990s.
A new study by Dr Claudia Henschke is reported in the New England Journal of Medicine today. Several researchers around the world screened 31,567 people at high risk of lung cancer.
Screenings of the participants were done between 1993 and 2005, with the vast majority having had repeated screenings a year later. Some 13% of those initially screened and 5% who had repeated screenings were found to have suspicious spots. Biopsies were performed on 535 patients; 484 were diagnosed with lung cancer, including 412 in the early stage. Most had surgery or chemotherapy and eight were untreated.
On calculating survival probability, researchers estimated that a 10-year survival rate, regardless of when the cancer was diagnosed or the type of treatment, was 80% with this increasing to 88% if the cancer was detected in an early stage, and 92% if such patients had surgery within a month of diagnosis.
The eight untreated patients all died within five years of diagnosis.
Following these results the Lung Cancer Alliance is urging doctors to regularly screen patients for lung cancer. President Laurie Fenton said, "This is the most important breakthrough for the lung cancer community that has ever happened."