Radioactivity Accident and Cancer Incidence in the Exposed Cohort

Abstract

P-255 Introduction: A vandalized radiotherapy unit carried out in the countryside of a developing country in the mid eighties caused an important radioactive accident in local population. Exposure risk assessment was feasible because radioactivity exposure measurements were performed after the accident. Since then, a specific health program was organized to provide regular health assistance for the affected cohort composed of 102 subjects. This paper presents an evaluation of the observed cancer incidence and overall mortality in the affected cohort during 18 yrs of follow up. Methods: Cancer incidence and overall mortality was ascertained for the period 1987–2002 and compared to that observed in the general population. Age and gender cancer incidence and mortality rates were used to estimate a standardized cancer incidence ratio (SIR) and a standardized mortality ratio (SMR), including the respective 95% confidence interval. Results: Two cases of cancer have been observed between 1987–2002, yielding a cancer SIR of 0.47 (95% C.I. 0.12–1.87). A statistically non-significant mortality excess (SMR 1.73, 95% C.I. 0.78–3.85) was observed. The 70% excess on mortality in the affected groups is not statistically significant, and therefore, chance cannot be ruled out to explain this observation. Discussion: These results did not support an association between such exposure and cancer incidence in the affected population. Continuous monitoring in the future of the affected cohort will probably provide more evidence to support or not the observed result. Conclusion: A lower than expected cancer incidence was observed in a population exposed during a radioactivity accident.