From the WebMD Archives
Nov. 29, 2004 (Chicago) — Young or old, smoking is a killer and its weapon of choice is often lung cancer. But results from a lung cancer screening study of almost 30,000 current and former smokers suggests that it may be possible to cut lung cancer deaths by widespread use of computed tomography (CT) screening.
Claudia I. Henschke, MD, PhD, professor of radiology at New York Hospital/Cornell Medical Center in New York, tells WebMD that while the risk of lung cancer increases with age and the number of cigarettes smoked, any smoking increases the likelihood of lung cancer.
For example, a 45-year-old who smokes less than 30 pack-years has about a 2 in 1,000 chance of developing lung cancer by age 55. But if that same 45-year-old has a “60 pack-year smoking history, which means smoking 3 packs a day for 20 years or 2 packs a day for 30 years, the risk goes up to 10 in 1,000,” she tells WebMD.
While those numbers are grim, Henschke says data from the ongoing lung cancer screening study — called the International Early Lung Cancer Action Project (I-ELCAP) — show that it is possible to detect lung cancer at its earliest stage, when it is not only treatable but curable.
She says about 170,000 new cases of lung cancer are diagnosed each year in the U.S. and about “160,000 of those people die. The cure rate is less than 10%.” But she says with annual screening using CT, “we can detect cancer before it has [spread] and the result is a cure rate of 76% to 78%.”
In addition to identifying the lung cancer risk for current smokers, Henschke says the data also indicate that the cancer risk does not immediately decline when a current smoker stops. “It takes at least 20 years for the risk to decrease. Up until 19 years after smokers quit the risk stays steady, and then it drops by half at 20 years,” she says.
Even when the risk drops, “former smokers always have a higher lifetime risk of lung cancer than never smokers.”
Henschke reported the findings at the annual meeting of the Radiological Society of North America.
Michael Brant-Zawadski, MD, medical director of radiology at Hoag Memorial Hospital in New Port Beach, Calif., tells WebMD that as a former smoker, he was surprised that it took so long for the lung cancer risk to decrease. “But I think that the value of CT for lung cancer screening is fairly clear. Women are having regular mammograms, but it may be that a large population will need annual ‘lungograms.'” Brant-Zawadski was not involved in the study.
Thus far the study has conducted lung CT images of 27,701 men and women and 19,371 repeat screenings.
Asked if it is time to recommend widespread lung cancer screening with CT, Henschke says, “I think it is useful for each person to make an individual decision based on his or her own circumstances.” She says that CT screening exams cost about $300 “but that cost can be significantly less — $150 or so — or much higher, based on location.” She says some insurers, for example Empire Blue Cross/Blue Shield in New York, are offering to pay for CT screening for some patients.
The U.S. Preventive Services Task Force neither endorses nor opposes lung cancer screening with CT, traditional X-rays, or sputum tests, saying that there is insufficient evidence to support or oppose screening.
Henschke says one concern raised about lung cancer screening with CT is that it exposes people to radiation, but she notes that the screening CT protocol used in her study “uses about the same amount of radiation as a routine chest X-ray. I don’t hear anyone objecting to annual chest X-rays.”
