Prolonged Lung Cancer Screening Boosts Mortality Benefit

39% Cut in Relative Risk of Cancer Death at 10 Years

Roxanne Nelson, RN, BSN

April 18, 20193

Extending lung cancer screening in individuals beyond 5 years can significantly impact the survival benefits associated with early disease detection, reports a new study.

The 10-year results of The Multicentric Italian Lung Detection (MILD) study showed a significant 39% reduction in the relative risk of lung cancer mortality among patients who underwent low-dose computed tomography (LDCT).

In addition, there was also a 20% risk reduction in overall mortality.

“The study demonstrates the significance of lung cancer screening in defined high-risk groups,” commented Fred Hirsch, MD, PhD, executive director at the Center for Thoracic Oncology in the Tisch Cancer Institute at Mount Sinai, New York City. “That is the main message here.”

Hirsch, who was not involved in the study and was asked to comment, noted that the study adds to previous data and addresses the question of how long screening should continue. “The MILD study did not show any significant difference in mortality after 5 years. But after 10 years, there was a difference in lung cancer and overall mortality,” he said in an interview. “That is an important message and needs to be discussed.”

The results were published online April 1 in the Annals of Oncology. 

The landmark National Lung Screening Trial (NLST), which published its principal findings in 2010, is the largest randomized study of lung cancer screening in a high-risk population to date, and reported that LDCT reduces mortality from lung cancer. At a median follow up of 6.5 years, the 53,000-person trial found a 20% reduction in deaths from lung cancer among current and former heavy smokers screened with LDCT as compared with chest x-ray screening.

More recently, a second large trial has also shown that a population-based lung cancer screening program can significantly lower the mortality risk for high-risk former and current smokers. New data from the NELSON study, conducted in the Netherlands and Belgium and presented last fall at the 19th World Conference on Lung Cancer (WCLC), showed an even greater reduction in deaths from lung cancer than was seen in the NLST.

Comprised of about 16,000 participants, NELSON demonstrated that LDCT screening reduced lung cancer deaths by 26% in men and up to 61% in women, compared with the control group at a follow-up of 10 years.

However, the authors of the MILD study note that several small European randomized clinical trials testing LDCT vs observation showed no benefit at the 5-year mark, which may have been partly because of the small number of patients and a short follow-up period. Their own 5-year results showed no evidence of a protective effect of annual or biennial LDCT screening (Eur J Cancer Prev. 2012;21:308-15).

The European studies collectively have also tended to enroll younger patients with a lower lung cancer risk than the NLST and have heterogenous selection criteria. Also, most offered annual LDCT screening rounds for 4 years or less, where the impact of screening duration and intensity is not evaluable.