Annual CT screening can detect curable lung cancer in high-risk patients

More than 80% of individuals who were diagnosed with lung cancer as a result of annual CT screening presented with stage I disease.

Issue: December 1, 2006

Annual spiral computed tomography screening detected curable lung cancer, according to a recent study.

“Using the original data from the Early Lung Cancer Action Program, we found CT screening for lung cancer to be highly cost-effective,” said Claudia I. Henschke, MD, PhD, from the New York Presbyterian Hospital—Weill Medical College of Cornell University.

Cost-effectiveness estimates for CT screening were similar to that for mammography screening for breast cancer, the researchers reported in The New England Journal of Medicine.

Routine screening

The Early Lung Cancer Action Program previously launched a study of the early diagnosis of lung cancer in cigarette smokers with the use of annual spiral CT screening. Researchers found that more than 80% of individuals who were diagnosed with lung cancer following an annual CT presented with stage I disease.

Henschke and fellow ELCAP researchers determined that, for baseline screening, a positive result on the initial low-dose CT scan was defined as the identification of at least one solid or partly solid noncalcified pulmonary nodule 5 mm or more in diameter, at least one nonsolid noncalcified pulmonary nodule 8 mm in diameter or a solid endobronchial nodule.

For annual screenings, a positive result was any new noncalcified nodule, regardless of size. If no new nodule was present, CT was repeated 12 months later, according to the researchers.

The protocol provided recommendations for the diagnostic workup in participants with a positive result on CT, with the decision of how to proceed left to each participant and the referring physician.

A total of 31,567 asymptomatic men and women underwent baseline screening between 1993 and 2005. The participants, who were aged at least 40 years, were at risk for lung cancer because of a history of cigarette smoking, occupational exposure or exposure to secondhand smoke. Individuals from Azumi, Japan, participated as part of an annual health-screening program. All participants were considered fit to undergo thoracic surgery.

All patients diagnosed with lung cancer were followed annually by the lead researcher and by the study coordinator at each participating institution.

Cost-effective approach

Of the 484 patients who received a lung cancer diagnosis, 411 underwent resection; 57 received radiation, chemotherapy or both; and 16 received no treatment. The estimated 10-year survival rate, regardless of tumor stage and treatment, was 80%. As of May 2006, 75 of the 484 participants had died of lung cancer.

There were 412 patients diagnosed with stage I lung cancer: 88% of these patients were alive at 10 years. The median stage I tumor was 13 mm in diameter.

For the 302 patients who underwent resection within one month after diagnosis, 10-year survival was 92%. The eight patients who opted for no treatment died within five years after diagnosis.

Henschke and colleagues said these results justify screening people who are at risk of lung cancer. The cost of low-dose CT is less than $200, and surgery for stage I lung cancer is less than half the cost of late-stage treatment.

“Using the original ELCAP data and the actual hospital costs for the workup, we found CT screening for lung cancer to be highly cost-effective,” Henschke said.

Jumping the gun?

The article by Henschke et al is both interesting and provocative, said Hem/Onc Today’s Lung Cancer Section Editor Joseph Aisner, MD, professor of medicine and chief of oncology at the Cancer Institute of New Jersey in New Brunswick. “The authors should be congratulated on the diligent effort at screening for lung cancer. The technology is evolving, and the published results look promising; however, I take some issue with the conclusions. These data do not prove the efficacy of screening chest CT scans, regardless of whether it ultimately proves correct or not — and I hope that it will prove correct. The majority of the cases were prevalence cases (and might have been found anyway). Only 74 were incident cases, and there were no detected interval cases. The cost-effectiveness should be determined by savings in life years, not the cost of the test by itself.

The criteria for effective screening tests include

specificity and sensitivity,
applicability to a large population (at low cost), and
the screened population must have a better overall survival than the nonscreened population.

“The issue should be resolved with the evaluation of the randomized trials (more than one year hence). The danger in touting this ELCAP study as an answer is that the randomized trials could become ‘contaminated’ by cross over in the control group. If we do not get a definitive answer, it could immortalize an unsubstantiated test such as prostate specific antigen testing in elderly men, which is now believed to likely cause more harm than good. The advocates’ argument, that while we wait for the randomized trials many people will die, is not new and was the argument that prolonged the (negative) answer for auto BMT in breast cancer. A similar argument led to the immortalization of PSA as a screening test and it has led to too many unnecessary and invasive procedures. We have finished the accrual to the more definitive randomized trials; a real answer will come, so let us not jump the gun, and await the results before ‘standardizing’ the chest CT scan for screening.” – by Rebekah Cintolo

For more information:

Henschke CI, Yankelevitz DF, Libby DM, et al. Survival of patients with stage I lung cancer detected on CT screening. N Engl J Med. 2006;355:1763-1771.