Diagnosing early-stage lung cancer with low-dose computed tomography (CT) screening may improve 20-year survival rates, according to a recent study published by Henschke et al in Radiology. The new findings demonstrated the significance of routine early screenings to detect tumors when they are small enough to be cured.
Background
In the United States, the average 5-year survival rate is 25.4% for all patients with lung cancer because only 21% of them are diagnosed with early-stage lung cancer. Further, over 50% of those with lung cancer die within 1 year of their diagnosis—making it the leading cause of cancer mortality. By the time symptoms appear, it is often too late.
“Symptoms occur mainly in late-stage lung cancer,” noted co–study author Rowena Yip, PhD, MPH, Senior Biostatistician at the Early Lung and Cardiac Action Program at the Icahn School of Medicine at Mount Sinai. “Thus, the best way to find early-stage lung cancer is by enrolling in an annual screening program,” she continued.
Although the treatment of more advanced cancer has progressed with the advent of targeted therapy and immunotherapy, the best tool against lung cancer mortality may be early diagnosis through low-dose CT screening before symptoms occur. However, estimates currently show that fewer than 6% of eligible patients undergo recommended screenings.
“While screening doesn’t prevent cancer from occurring, it is the major tool to identify lung cancers in their earliest stage when they can be cured,” explained lead study author, Claudia Henschke, PhD, MD, Professor of Diagnostic, Molecular, and Interventional Radiology and Director of the Early Lung and Cardiac Action Program at the Icahn School of Medicine at Mount Sinai. “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,” she added.
Study Methods and Results
In a large-scale international study, researchers analyzed the 20-year survival rates of patients who underwent low-dose CT screening to detect lung cancer.
Patients who were diagnosed with lung cancer via CT screening had a 20-year survival rate of 81%. Among the 1,257 patients who were diagnosed with lung cancer, 81% of them had stage I disease, and their long-term survival rate was 87%. If diagnosed at the earliest stage I, with a tumor size of ≤ 10 mm, the survival rate increased to 95%.
Dr. Henschke and her colleagues have assessed the efficacy of cancer detection with low-dose CT screening for years. Their efforts to advance CT screening for early lung disease led to the creation of the International Early Lung Cancer Action Program in 1992. Since its inception, the multi-institution, multinational research program has enrolled more than 89,000 patients from over 80 institutions. In 2006, the researchers discovered that the patients whose cancer was identified by CT screening had a 10-year survival rate of 80%.
Conclusions
“What we present here is the 20-year follow-up on [patients] in our screening program who were diagnosed with lung cancer under annual screening and subsequently treated. The key finding is that even after this long a time interval, they are not dying of their lung cancer—and even if new lung cancers were found over time, as long as they continued with annual screenings, they could be cured,” Dr. Henschke highlighted. “Ultimately, the critical clinically relevant information for [patients] interested in screening relates to understanding their chance of being diagnosed with lung cancer, and if detected during screening, how curable it would be compared to being diagnosed based on symptoms,” she concluded.
The U.S. Preventive Services Task Force currently recommends annual lung cancer screenings with low-dose CT scans in patients aged 50 to 80 years who have a 20 pack-year smoking history and who currently smoke or have quit within the past 15 years.
Disclosure: For full disclosures of the study authors, visit pubs.rsna.org.
