Report from RSNA: Survival data spur CT lung screening surge

November 28, 2004

CT screening of high-risk patients can find lung cancers early. It can also keep patients alive.

CT screening of high-risk patients can find lung cancers early. It can also keep patients alive.

For the first time, researchers at the RSNA meeting were able to show a correlation between early detection, the resulting treatment, and long-term survival for lung cancer. Data from the International Early Lung Cancer Action Project (I-ELCAP) indicate that up to 95% to 98% of lung cancers caught at stage IA and treated can be cured. Screening can give patients years of added survival.

Equally promising, the percentages of lung nodules that need to be treated at baseline (15%) and each subsequent year of screening (6%) are low enough that such screening need not unduly burden the healthcare system. Critics voiced fears of such a consequence during the study's early years.

Patients can be triaged based on their existing risk factors, such as age and smoking history, to determine if yearly screening is appropriate.

"We've always evaluated diagnosis and treatment separately in this study, and we're just now getting the treatment results," said investigator Dr. Daniel Yankelevitz, director of inpatient radiology at New York Weill Cornell Medical Center. "We're getting to be able to stratify whom to screen and, after one screening, to determine the benefit of a second screen."

The I-ELCAP has collected lung screening information for 27,701 patients in the U.S. and at international collaboration sites. Demographic data for the population have allowed the investigators to begin categorizing and predicting patient risk. When a stage I cancer is found at baseline, patients have an average 76% chance of being cured if standard treatment is initiated, said lead investigator Dr. Claudia Henschke, chief of chest imaging and healthcare policy and technology assessment at New York Weill.

The number rises to 78% for stage IA cancers found on subsequent yearly screenings. Without screening, only 5% to 10% of patients are likely to be cured. More than 80% of cancers found on screening were stage I. Among ELCAP patients who had lung cancers resected, the eight-year lung cancer fatality rate was 4%.

Henschke presented a calculation of patient age, smoking history, cessation of smoking, and other factors that can help determine whether a patient is an appropriate candidate for such screening. Comorbidities and overall expected survival for at least 10 years can affect whether the patient will receive the full benefit of the screening.

With added long-term follow-up, ELCAP and other studies are beginning to sort out the thorny question of which lung masses need follow-up, and how fast. A subset of ELCAP patients had mediastinal nodules, of which nearly 90% stayed the same size year to year or shrank on their own. Setting up a watch-and-wait plan for appropriate masses can decrease unnecessary procedures.

For suspicious lung nodules, however, early action is key.

"Deaths from stage I lung cancer were surprisingly low after surgery," Henschke said, "but only if treatment is pursued. Delaying treatment by more than six months resulted in increased tumor disease and often a higher stage of the disease."