Diagnosing early-stage lung cancer using low-dose computed tomography (CT) screenings may improve patients’ long-term survival rate, according to long-term findings from the International Early Lung Cancer Action Program presented at the Radiological Society of North America (RSNA) 2022 Annual Meeting.

Background

“While screening doesn’t prevent cancers from occurring, it is an important tool in identifying lung cancers in their early stage, when they can be surgically removed,” said lead study author Claudia Henschke, PhD, MD, Clinical Professor of Diagnostic, Molecular, and Interventional Radiology as well as Director of the Early Lung and Cardiac Action Program at the Icahn School of Medicine at Mount Sinai Health System.

The average 5-year survival rate for patients with lung cancer is 18.6%, according to the American Lung Association. Only 16% of lung cancers are diagnosed at an early stage, and more than 50% of patients with lung cancer die within a year of diagnosis.

While treatments of more advanced-stage cancers with targeted therapy and immunotherapy have come a long way, the best tool in the fight against lung cancer mortality is early diagnosis through low-dose CT screenings before symptoms appear.

“Symptoms occur mainly in late-stage lung cancer,” Dr. Henschke explained. “Thus, the best way to find early-stage lung cancer is by enrolling in an annual screening program.”

International Early Lung Cancer Action Program and 20-Year Study Results

In a large-scale, international study, Dr. Henschke and her colleagues examined the effectiveness of cancer detection with low-dose CT screenings. The efforts of the researchers to advance CT screenings for early lung disease led to the creation of the International Early Lung Cancer Action Program in 1992, which has since enrolled over 87,000 participants from over 80 institutions internationally.

In 2006, the researchers identified a 10-year survival rate of 80% for the patients whose cancers were identified by CT screenings. For this study, they looked at the 20-year survival rates.

“What we present here is the 20-year follow-up on participants in our screening program that were diagnosed with lung cancer and subsequently treated,” said Dr. Henschke, highlighting that “The key finding is that even after this long a time interval, they are not dying of their lung cancer.” 

The study found that the 20-year survival rate was 80% for the 1,285 patients who were diagnosed with early-stage lung cancer. The survival rate for both the 139 patients with nonsolid cancerous lung nodules and the 155 patients with nodules of part-solid consistency was 100%. For the 991 patients with solid nodules, the survival rate was 73%.

The researchers also estimated that the survival for patients with clinical stage IA lung cancers and for resected pathologic stage IA lung cancers—measuring 10 mm or less in average length and width diameter on the same CT image—was 86% (regardless of consistency) and 92%, respectively.

Conclusions

The results showed that after 20 years, patients diagnosed with lung cancer at an early stage via CT screenings had significantly better outcomes. By surgically removing the cancer when it was small enough, researchers discovered that patients may have been effectively cured in the long term—a discovery that demonstrates the importance of routine and early screening.

The U.S. Preventive Services Task Force recommends annual low-dose CT screenings for lung cancer for adults aged 50 to 80 years who have a 20 pack-year smoking history, and currently smoke or have quit smoking within the past 15 years.

“Ultimately, anyone interested in being screened needs to know that if they are unfortunate enough to develop lung cancer…it can be cured if found early,” underscored Dr. Henschke.