Low-Dose CT Screening Detects NSCLC: ELCAP Update

CHICAGO—Although the incidence of non-small-cell lung cancer (NSCLC) is similar to that of other types of cancer, the death rate tends to be higher because lung cancer often is not detected until it is the size of an orange. “There is no reason why the death rate for lung cancer cannot be reduced to the levels seen with other cancers if high-risk patients undergo regular screening and lesions are found when they are the size of a grain of rice,” Claudia I. Henschke, MD, PhD, said at the 85th Annual Meeting of the Radiological Society of North America (RSNA).

Dr. Henschke, professor of radiology and chief of the Division of Chest Imaging, Weill Medical College of Cornell University, New York, reported on the results of the second year of the Early Lung Cancer Action Program (ELCAP).

In its first year, ELCAP enrolled 1,000 men and women aged 60 years or older who had a strong history of cigarette smoking; enrollees smoked at least a pack of cigarettes a day for 10 years or two packs a day for 5 years.

An Unanticipated Benefit of Screening

A related study of subjects enrolled in ELCAP showed an unexpected benefit of CT screening: 23% of those in the study were convinced to quit smoking. A majority said that reviewing their CT scans with the ELCAP radiologists provided the motivation to quit. Another 23% of subjects were convinced to cut back on smoking. In contrast, the national annual rate of smoking cessation is about 6%.

When reviewing the CT images for possible lung cancer, the study subjects were also shown their extent of emphysema. “Emphysema makes the lungs look like Swiss cheese with big empty holes in place of the normal lung tissue, and many people in the study were unaware that they had this disease,” Dr. Henschke said.

Of these 1,000 high-risk individuals, 808 have had a baseline and a repeat low-dose CT screening examination. Dr. Henschke presented findings from multiple CT studies of these 808 individuals, which provided a total of 1,398 person-years of annual CT screening.

Repeat annual CT screening identified one to six noncalcified nodules (new or previously undetected at baseline screening) in 78 individuals, for a detection rate of 5.6%. Of 11 patients with nodules selected for biopsy, based on study criteria, nine were found to have malignant lesions.

Low-dose CT screening produced “a dramatic improvement” in the detection of early-stage NSCLC, Dr. Henschke said. Baseline CT screening, which was reported at the 1998 RSNA meeting, detected 27 of 28 lung cancers, 23 (85%) of which were stage IA. Repeat CT examination found all nine malignancies diagnosed at biopsy, eight NSCLCs and one small-cell lung cancer. Seven of the eight NSCLCs (88%) were stage IA.

According to Dr. Henschke, previous randomized trials have shown that if NSCLC is found at an early stage and managed with surgical resection, the survival rate approaches that of other cancers that are found through screening and treated promptly. Dr. Henschke stated, therefore, that regular CT screening of individuals who are at high risk for NSCLC may identify patients with stage IA disease suitable for surgical resection and improve the survival rate for NSCLC to 80% or higher.

Dr. Henschke’s coauthors were Drs. David Naidich, David Yankelevitz, Dorothy McCauley, Georgeann McGuinness, James Smith, Daniel Libby, Mark Pasmantier, and Olli Miettenen.