Can This Test Save 100,000 Lives a Year?
For: "Full-Body
Scans—Peace of Mind at a Price?" December 2002
Lung cancer kills more men and women in this country and Canada every year than any other cancer—more than breast, prostate, and colon cancer combined. Yet there are no best-selling books or films about how to cope with lung cancer, though some support groups do exist. No pressure groups lobby Congress for research funds.
And millions are at higher than average risk for lung cancer, by reason of having smoked in the past or continuing to do so: 90% of all lung cancer cases are caused by cigarette smoking. The risk begins to decline as soon as you quit, but will never be as low as it is for people who have never smoked. There is no way so far to detect lung cancer early enough to cure it. The five-year survival rate at diagnosis is less than 13%. If the cancer is diagnosed early enough and can be surgically removed, the five-year survival rate can be 70%. But this rarely happens.
What's urgently needed, in addition to better treatments, is a reliable screening method for healthy people—long before they show symptoms of the disease. And there may be such a method soon. Last fall a study in the Lancet from the Early Lung Cancer Action Project, funded by the National Institutes of Health, showed that spiral CT scans—computed tomography, a computer-assisted body-imaging technique—were better than traditional chest X-rays at detecting early lung cancer. (Regular chest X-rays were long ago abandoned as a screening method for healthy people because most early cancers are too small to show up on them, and studies finally proved that chest X-rays for early lung cancer do not save lives.)
Using spiral CT scans and chest X-rays, the new study examined 1,000 people aged 60 or older who had smoked at least a pack a day for 10 years (or half a pack a day for 20 years) and had no symptoms. Spiral CT scans identified 233 people with suspicious-looking patches in their lungs, who were followed up with high-resolution CT scans and, when necessary, surgical biopsies. In the end the CT scans identified 27 cancer cases (in comparison, chest X-rays found 68 suspected cases, only 7 of which were actually cancer). These early-stage cancers were surgically removed, presumably before they had spread, thus increasing the chances for survival.
Newspaper headlines subsequently proclaimed that this test could save 100,000 lives each year in the U.S. alone. But could it?
Smokers rush to be tested
This news resulted in a small stampede, with many hospitals offering CT scans for smokers and former smokers. Many former smokers who smoked a pack a day for ten years are wondering if it would be wise to ask for the test. Obviously, this is something you may want to discuss with your physician.
But here's the down side of CT scans for early lung cancer:
• Though the initial test itself is quick and painless, the follow-up—should you prove to have suspicious nodules—may not be. Though 27 cases of cancer were eventually identified by the CT scan, that left about 200 patients who underwent unnecessary tests (with the attendant anxiety) for a disease they did not have.• This research is in its early stages. No one is certain that the people in this study whose cancer was treated early will actually live longer. Lung cancer is among the deadliest of all cancers. Early treatment (usually surgery and radiation) should add years to a person's life, or even cure the disease, but no one knows for sure whether early detection really means improved survival. Not enough early cases have been followed so far.
• No one, at this point, knows how many cancers the CT scan failed to detect. Is it reliable? That remains to be seen.
• As a practical matter, there aren't enough screening facili-ties and trained professionals to screen the 100 million current and former smokers in this country.
Bottom line: It's too early for mass CT scan screening of smokers and former smokers. It's a fairly expensive test ($300 or more, not counting follow-up). Nevertheless, if you were a heavy smoker, or are still smoking, or if there's a history of lung cancer in your family, you may want to consider screening. Insurance, by the way, usually will not cover it. Additional studies of CT scans are underway, and simpler tests (such as blood tests) may one day be developed, too.
Meanwhile, what's urgently needed is more money for stop-smoking programs and for educating young people about the dangers of smoking. Belatedly, there is a lapel ribbon aimed at raising public awareness of lung cancer: clear acrylic, to symbolize "invisibility." There's also a hotline (800-298-2436) and a website (www.alcase.org) for patients.
UC Berkeley Wellness Letter, July 2001
