Cancer
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Randomized Controlled Trial Comparative Study Clinical Trial
Czech Study on Lung Cancer Screening: post-trial follow-up of lung cancer deaths up to year 15 since enrollment.
The study was launched in the mid-1970s to explore the capability of screening by chest X-ray and sputum cytology to be used as an effective component of the lung cancer control program in the Czech Republic, a Central European country with a high and increasing occurrence of lung cancer in men at that time. A complementary objective of this report is to ascertain whether the cumulative numbers of lung cancer deaths would equalize in the two randomized groups during a prolonged follow-up period. ⋯ The study gave no evidence that screening for lung cancer by chest X-ray is beneficial in terms of reducing mortality. Based on the results of this study, there is no justification to recommend semiannual screening as a component of a comprehensive lung cancer control program.
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For heavy cigarette smokers and recent former smokers who have accumulated a high risk of lung carcinoma, a primary objective is the early detection of that disease; this goal can be achieved by annual screening with one of the radiologic imaging methods available. While awaiting for the implementation of computed tomography or of other, more sensitive methods, it is quite reasonable to screen those who are at risk with annual chest X-ray (CXR), an examination that is readily available at low cost. Indeed, with the annual CXR screening of heavy smokers, it is possible to detect about 50% of lung carcinomas in TNM Stage I. The 5-year survival rate of patients with asymptomatic, screen-detected Stage I disease after radical surgery is significantly greater than the survival rate of patients with symptomatic disease. ⋯ In the province of Varese, Italy, it is possible to make an early diagnosis of lung carcinoma with CXR annual screening in asymptomatic, high risk smokers. Incidence screening in 1361 participants detected 7 patients with asymptomatic lung carcinoma; 5 of 7 patients (71%) with such screen-detected lung carcinoma had Stage I disease.
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Because the mortality rate from lung cancer is increasing sharply in Japan, lung cancer screening is being performed actively to assure early diagnosis and early treatment. However, its effectiveness is not clear, because it is extremely difficult to diagnose early microcarcinoma of the lungs (< 1 cm in greatest dimension) with the indirect X-rays that are used in mass screening. Therefore, the authors compared differences in the study population by gender and by age and economic class with the present method for mass screening of lung cancer as well as with computed tomography (CT) screening from the standpoint of cost-effectiveness. ⋯ The results show that the present method used in lung cancer screening is cheaper, but its effectiveness is also low; and, although the cost of screening by CT is higher than that of the present screening method, it is much more effective. Lung cancer screening by CT should become the most appropriate screening method with respect to cost-effectiveness.