Antonin Kubik

Czech study on lung cancer screening

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.

Adenocarcinoma of the lung among women: risk associated with smoking, prior lung disease, diet and menstrual and pregnancy history

To investigate the role of tobacco and some other known or suspected factors responsible for the risk of developing adenocarcinoma of the lung, and to compare with other cell types (squamous-, small- and large-cell cancers) in Czech women, we conducted a case-control study. Data collected by personal interviews from 145 cases of adenocarcinoma of the lung, 221 lung cancer cases of other cell types, and 1624 controls were analyzed using unconditional logistic regression. Cigarette smoking was the main determinant of all major cell types of lung cancer among Czech women, its effect was weaker on adenocarcinoma than on squamous-, small- and large-cell cancers. Among never smokers, passive smoking in childhood (before age 16) did not significantly increase the risk of adenocarcinoma (OR=1.35, 95%CI 0.75-2.45), contrasting with an elevation in the risk of squamous-, small- and large-cell cancers combined (OR=2.10, 95%CI 1.02-4.33). Excess risk associated with consumption of red meat daily or several times per week (OR=1.81, 95%CI 1.04-3.18) was restricted to squamous-, small- and large-cell cancers combined. Wine drinking, at higher frequency than once per month, was inversely associated with the risk of adenocarcinoma (OR=0.46, 95%CI 0.23-0.92), however, not with squamous-, small- and large-cell cancers combined (OR=0.77, 95%CI 0.47-1.28). Inverse associations with the risk of squamous-, small- and large-cell cancers combined emerged for the quantity of menstrual flow (OR=0.63, 95%CI 0.40-0.99), and pains or mental tension related to menses (OR=0.61, 95%CI 0.42-0.89).

A case-control study of lung cancer among Czech women

Few data are available to explain the continuing increase in lung cancer mortality among Czech women. The study was designed to examine the role of active smoking and other known or suspected factors. Data collected by personal interviews during the 15 months of a hospital-based case control study are reported. A total of 140 microscopically confirmed cases and 280 frequency-matched controls were analysed using multiple logistic regression. Cigarette smoking was the most important factor associated with excess risk for lung cancer among women. Significantly increased risk was found both among current smokers (OR=11.20, 95% CI 5.9-21.2), and ex-smokers (OR=10.02, 95% CI 5.5-18.4). Positive dose-response gradients (P<0.001) were observed between lung cancer risk and the daily number of cigarettes, duration of smoking, number of pack-years, inhaling, and grade of nicotine dependence assessed by the Fagerström test (Heatherton TF, Kozlowski LT, Frecker RC, Fagerström KO. Br J Addict 1991;86:1119-1470; Pomerleau OF. In: Bolliger CT, Fagerström KO, editors. The Tobacco Epidemic. Basle: Karger, 1997: 122-131). Exposure to environmental smoke was associated with elevated lung cancer risk (OR=3.58, for lifetime non-smokers exposed both in childhood and in adult age). Physical exercise and body mass index were inversely associated with lung cancer risk. For the category of physical exercise of more than 5 h per week, the odds ratio was 0.38, compared to subjects admitting no physical exercise. For body mass index, the odds ratio for the highest (compared to the lowest) quartile was 0.50. Chronic cough and phlegm (at least 3 months per year) were associated with excess risk (OR=6.07) only if their duration was less than 2 years before diagnosis of lung cancer, and, therefore, they were suspected of being more likely early symptoms of preclinical lung cancer rather than its cause. Our results support the statement that cigarette smoking is by far the most important cause of the on-going epidemic of lung cancer among Czech women, and are consistent with the concept of a balance between risk and protective factors whose eventual maintenance or alteration determine the development of disease (as suggested by Rylander R, Axelsson G, Andersson L, Liljequist T, Bergman B. Lung Cancer 1996;14(Suppl 1): S75-S83). Concerted control of smoking appears to be an urgent priority in lung cancer prevention among women, including specific approaches targeted on the female population.

The natural history of lung cancer estimated from the results of a randomized trial of screening

The results from a randomized controlled trial of screening for lung cancer in Czechoslovakia have been used to estimate parameters of the natural history, using a model to simulate the disease process and the effects of screening. The results suggest that the period before clinical presentation during which lesions can be detected by screening is very short (seven to eight months). This implies that to detect three-quaters of all lung cancers by screening, two examinations per year are necessary, and that such a program would advance diagnosis by six months if there were complete participation. The results of the trial itself suggest that the benefit, in terms of a reduction in mortality from lung cancer, is likely to be very small.