Lung Cancer Mortality in the Mayo Lung Project: Impact of Extended Follow-up

Reviewers: Li Liu, MD
Source: Journal of the National Cancer Institute, Volume 92:1308-1316, (August) 2000

Précis: Screening does not reduce long-term lung cancer mortality

Introduction

At present, there is widespread acceptance that screening for the early detection of lung cancer is not indicated. The American Cancer Society and the National Cancer Institute (NCI) recommend against efforts for early detection of lung cancer by mass screening (Ann Intern Med 1989 Aug 1;111(3):232-7). An early report of the Mayo Lung Project observed no reduction in lung cancer mortality with an intense screening regimen consisting of chest x-ray and sputum cytology. In this report, the researchers updated their results with extended follow-up and more participants.

Method

A total of 9211 male smokers were randomly assigned to either undergo a chest x-ray and sputum cytology every 4 months for 6 years (screening group) or were advised to have the same tests annually (usual care group).

Results

• Lung cancer mortality was 4.4 per 1000 person-years in the screening group and 3.9 per 1000 person-years in the usual-care group, which was not statistically different.
• The median survival after diagnosis for the screened group was 1.3 years compared with 0.9 years for those in the usual-care group.
• For those with resected early-stage disease, the median survival was 16 years in the screened group compared with 5 years in the usual-care group, although this was not statistically significant.

Discussion

After an extended follow-up, the researchers of the Mayo Lung Project concluded that intense screening of smokers by chest x-ray and sputum cytology did not reduce the lung cancer mortality rate, but did appear to increase survival length. This study suggests that such screening may be identifying lung cancers earlier, but with limited clinical relevance.