Lung cancer is the number one cancer killer -- more deadly than breast, prostate, cervical and colon cancers combined. Of the 173,000 people who are newly diagnosed with lung cancer each year, a staggering 95 percent will eventually die from it.
Early screening tests for other cancers -- such as mammography and colonoscopy -- can find tumors in their early and more treatable stages. For lung cancers, however, no proven screening test exists. But researchers think they may have found one.
For more on the study, watch "Healthy Life" on ABC News Now at 10:05 this morning.
A new study to be published Thursday in the New England Journal of Medicine says that a powerful scanner, the spiral CT, can detect very small and early stage lung cancers. The researchers suggest that this early detection may help more people get effective treatment and survive this devastating disease longer.
Largest Study of Its Kind Suggests CT Scans Benefit Patients
This is the largest longterm study to show that the CT scan may be beneficial in catching early lung cancer. Led by researchers at NewYork-Presbyterian/Weill Cornell Hospital, the data was collected as part of the International Early Lung Cancer Action Program (I-ELCAP).
Researchers from 38 hospitals in seven countries studied more than 30,000 people over age 40 with a high risk of developing lung tumors. This high risk group included smokers, nonsmokers exposed to secondhand smoke and people who worked with cancer-causing agents such as asbestos, uranium or radon.
None of the volunteers had what doctors consider to be warning symptoms of lung cancer, such as a cough that doesn't go away, shortness of breath, hoarseness, bloody spit or weight loss.
Researchers ran 31,567 volunteers through a CT scanner and evaluated suspicious spots found on the CT scan. If those spots met the criteria for possible lung cancer, patients were offered immediate treatment. If not, patients were followed-up at subsequent times to chart the growth of the abnormality.
Eventually, doctors identified 484 people with lung cancer -- of which 412 were in the smallest and earliest stage of the disease. At this early stage, lung cancer can be very curable, especially with surgery.
Unfortunately, lung cancer is usually caught at later stages, when it may have already spread to other body parts and when it is too late for treatments to make much of a difference.
Early Detection Means Early Treatment
Because doctors found the tumors early, patients were treated quicky, before the disease had progressed to a serious stage.
Researchers estimated that 88 percent of these people would be alive at 10 years because of this early treatment -- a much better prognosis than usual. Doctors also estimated that more than 90 percent of the 302 who had their tumor removed would be alive at 10 years.
All patients who didn't undergo any treatment -- neither surgery, nor chemotherapy, nor radiation -- died within five years of the diagnosis.
Study authors say that CT screening can find more curable cancer and they suggest that the American Cancer Society should revise its current guidelines -- which do not recommend early lung cancer screening -- to incorporate CT screening as an early detection test.
"We believe this study provides compelling evidence that CT screening for lung cancer can cure the disease and save lives," said Dr. Claudia Henschke, lead study author and chief of the chest imaging division at NewYork-Presbyterian/Weill Cornell Hospital.
But the American Cancer Society does not currently recommend lung cancer screening because of the lack of hard evidence that early detection of lung cancer actually prevents deaths.
Screening Does Not Save Lives, Say Some
"We do not recommend lung cancer screening at this time because there is not sufficient data to support that people at high risk should undergo screening," says Dr. Robert Smith, Director of Screening at the American Cancer Society.
Other experts point out that since CT scanners are very good at picking up the tiniest cancers -- even ones that may look like cancer under the microscope but may not be lethal -- some of the people who survived in this study could be people who weren't going to die from their cancer even without treatment.
"These are cancers that one dies with but not from," says Dr. Denise Aberle, professor of radiology at the UCLA Jonsson Comprehensive Cancer Center. Hence, these findings could falsely suggest that more people are surviving the disease.
These experts say the key question is not whether early detection might allow some people to survive longer, but whether spiral CT can lower the mortality rate from lung cancer.
Most experts want that question answered before guidelines for screening can be made, and they believe that only a randomized controlled trial can do it. This special type of clinical trial is widely considered to give the best, most convincing scientific proof that a medicine or procedure really works.
Such a trial is currently under way. It is called The National Lung Screening Trial (NLST). Currently 50,000 volunteers in this trial are undergoing lung cancer screening by either CT or a standard chest x-ray. Researchers will then see if either screening method leads to fewer deaths from lung cancer.
Unfortunately, trial results are not expected until the end of 2009 -- and recommendations may change at that time.
Until recommendations do change, what are people to do if they are at high risk for lung cancer?
"[CT scanning] may be beneficial, but there are real risks as well," says Aberle, one of the lead researchers of the NLST. Harmless abnormalities may be picked up, for which patients may have to get extra tests or procedures. And there may be complications from these additional tests. There is also a risk from radiation exposure from repeated CT scans.
"Talk with your doctor about your risk of lung cancer," Smith says. Each person's individual risk should be discussed, along with the pros and cons of screening.
"And people who smoke should keep in mind that the best way to avoid dying from lung cancer is to stop smoking," according to the Web site of the American Cancer Society.