SUMMARY: The American Cancer Society estimates that for 2022, about 236,740 new cases of lung cancer will be diagnosed and 135,360 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers and Adenocarcinoma now is the most frequent histologic subtype of lung cancer.
In the National Lung Screening Trial (NLST) with Low Dose CT (LDCT) screening for lung cancer, there was a 20% reduction in mortality. Following the publication of the results of NLST, the NCCN issued guideline in 2011, and the United States Preventive Services Task Force (USPSTF) recommended lung cancer screening with Low Dose CT scan in high-risk patients. The CMS in 2015 determined that there was sufficient evidence to reimburse for this preventive service. The USPSTF expanded the criteria for lung cancer screening in 2021 and recommended annual screening with Low-Dose CT for adults aged 50-80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years.
Approximately 15% of patients present with early stage (T1-2 N0) disease, and these numbers are likely to increase with the implementation of lung cancer screening programs. Surgical resection is the primary treatment for approximately 30% of patients with NSCLC who present with early Stage (I–IIIA) disease. Despite the favorable stage shift as a result of lung cancer screening, low Health Care Provider knowledge of the lung cancer screening guidelines represents a potential barrier to implementation.
The Early Lung Cancer Action Project (ELCAP) in 1992 initiated a study of the early diagnosis of lung cancer in cigarette smokers using annual spiral CT screening. This study showed that more than 80% of individuals diagnosed with lung cancer as a result of annual CT screening had clinical Stage I cancer (Lancet 1999;354:99-105). In a subsequent large collaborative study (International Early Lung Cancer Action Program-IELCAP), 31,567 asymptomatic individuals at risk for lung cancer were screened with Low-Dose CT from 1993 through 2005. This study suggested that for those participants with Stage I lung cancer, the estimated 10-year survival rate was 88%, and among those with clinical Stage I lung cancer who underwent surgical resection within 1 month after the diagnosis, the survival rate was 92%. This study provided strong evidence that annual spiral CT screening can detect lung cancer that is curable (N Engl J Med 2006; 355:1763-1771).
The researchers herein provided the 20-year lung cancer-specific survival of participants, IELCAP enrolled, since its start in 1992. This prospective, international, multicenter study enrolled 87,416 participants, current, former and never smokers, 40 years of age and older, as of December 31, 2021. Participants were screened for lung cancer using Low-Dose CT for early detection of lung cancer with particular attention to lung cancer manifesting on CT images as solid, part solid and nonsolid consistency.
The 20-year lung cancer-specific survival for patients who underwent CT screenings and were diagnosed with early-stage lung cancer was 80%. The lung cancer-specific survival for patients with nonsolid and part-solid consistency cancerous lung nodules who underwent CT screenings was 100%, and 73% for patients with solid nodules. The lung cancer-specific survival for clinical Stage IA participants was 86%, regardless of consistency. For participants with pathologic Stage IA lung cancers 10 mm or less in average diameter, the 20-year lung cancer-specific survival was 92%.
The researchers concluded that after 20 years, their previous estimates of lung cancer survival rates are now confirmed, and this study adds further evidence of the high curability of lung cancer diagnosed by CT screening. These data demonstrate the importance of routine and early lung cancer screening.
20-year Lung Cancer Survival Rates in the International Early Lung Cancer Action Program (IELCAP). Henschke C, Yankelevitz DF, Libby DM, et al. Presented at: Radiological Society of North America; November 27-December 1, 2022; Chicago, IL.
