Semiannual chest film (SCF) screening for detection of lung cancer was assessed. According to the author, a useful screening procedure should be simple, inexpensive, convenient, reliable, sensitive, and specific. It should provide a significant yield of curable disease, improve the cure rate, and have a favorable cost benefit ratio. SCF had good specificity, low sensitivity, and poor yield of curable disease. Poor results showed by SCF studies were ascribed to the nature of lung cancer, the nature of the host, the peculiarities of the patient with lung cancer, the nature of current medical practices, and the nature of lung cancer. Lung cancer was observed to have a very rapid growth rate and metastasize early. A majority of lung cancers whose growth rate had been measured doubled in less than 6 months. Doubling time was inversely related to survival. Lung cancers were usually not detected until they were at least 1 centimeter in diameter. By that time, the tumor had passed through the first two thirds to three fourths of its lifetime. Compliance with SCF showed that in the Philadelphia Pulmonary Neoplasm Research Project (PNRP), the average probability of a patient having two consecutive chest SCF was 57 percent. The risk of lung cancer was higher in noncompliant male patients. Median age in the PNRP study was 64 years. Operative deaths among 968 patients operated on for lung cancer varied from 9.3 percent for the 50 years old to 19.4 percent for the over 70 year old cohort, respectively. Risk of lung cancer was also higher in subjects with chronic cough. In the PNRP, 6 percent of the delay in patients' care was attributed to patients' physicians. The prognosis for patients who had been successfully treated but continued to smoke was not as good. The author concludes that periodic chest x-rays were not adequate to reduce the mortality rate of bronchogenetic carcinoma in populations at risk.
Occupational Safety and Health Symposia 1979, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, DHHS (NIOSH) Publication No. 80-139