There is an impressive contrast in well-conducted surveys between the detection of curable tuberculosis and that of curable lung cancer. A significant amount of survey-found tuberculosis is minimal in extent and, therefore, amenable to present-day treatment, whereas, despite immediate emergency referral of persons whose photofluorograms were read "suspect neoplasm" at two official Philadelphia chest x-ray units, resection could be done in only 30% of a series of 100 consecutive cases. Of 52 persons in this group on whom a three year follow-up period has elapsed, only 5, or 9.6%, survived. Thus, the suitability of single photofluorograms for finding curable lung cancer must be questioned. There are few available data on the prevalence of proved survey-detected lung cancer. Scamman,1reporting on 536,012 persons surveyed in Boston in 1949, includes metastatic as well as "presumptive" carcinoma in a rate of 14.2 per 100,000. Only 43 cases are stated to have been