Use of the survival analysis methods for investigation of the association between chromosomal aberrations and carcinoma

Abstract

The primary purpose of this article is the analysis of data that come from 219 radon-mine workers who underwent cytogenetic analysis (or analyses) of peripheral blood lymphocytes. We focused on the connection between the cytogenetic analysis results (the occurrence of different types of chromosomal aberrations - chromatid and chromosome changes and breaks) and the occurrence of carcinoma. We also analyzed the influence of other explanatory variables, such as age, smoking, and the level of exposure to radon. We performed separate Cox analyses for the incidence of any type of cancer and for the incidence of lung cancer only as dependent variables. In the latter case, we found out that the only significant factors were the level of exposure to radon and the fact whether or not the subject ever smoked. As for the overall cancer incidence, we found two suitable models. Both models utilise age, smoking status, the level of exposure and the frequency of chromatid changes. In addition to these variables, the first model contains the frequency of chromatid breaks and the second model contains overall frequency of chromosomal aberrations. As the study was an expansion to the study of Šmerhovský et al. from 2002, we also compared our results with the results of this study. As for the overall incidence of cancer, the results were not markedly different from the aforementioned study. Regarding the lung cancer incidence, a significant association of chromosomal aberration frequency and chromatid breaks frequency had been found in the original study, while our findings showed that none of the aberrations were significant for the lung cancer incidence.