Carcinoma of the lung is the most common cause of death from cancer in
the United States. In considering lung cancer for possible chemopreve
ntion trials, we have analyzed the data collected by the collaborative
NCI program on early lung cancer. The data indicate that at least 12
years of study of 80,000 people at risk for lung cancer (adult male ci
garette smokers) would be required to establish a 25% reduction in squ
amous carcinoma of the lung. No intermediate markers of developing lun
g cancer are presently available to shorten the observation period. It
is concluded that a study of the magnitude required is not feasible a
t the present time. (C) 1993 Wiley-Liss, Inc.