[Ionizing radiation as a risk factor for thyroid cancer in Krakow and Nowy Sacz regions]

In a group of 224 patients with thyroid cancer registered from 1990 to 1999 and in 243 controls matched for sex and age doses for the thyroid due to accumulation of 131I after Chernobyl accident and radiological diagnostic procedures involving the neck and dentition was calculated according to Johnson's model and based upon questionnaires. There was a significantly higher dose for the thyroid due to accumulation of 131I in the Krakow area in comparison with the Nowy Sacz area. There was also a significantly higher frequency of radiological procedures involving the thyroid gland preceding the development of thyroid cancer in comparison with the control group. The present findings are concordant with about 40% increase of thyroid cancer in the Krakow area in comparison with the Nowy Sacz region. The present study has indicated that ionising radiation may be a factor involved in the pathogenesis of thyroid cancer and its significant rise within the last 10 years. However, it has not been the main factor, but only one of the risk factors. The study has also indicated that iodine prophylaxis should be continued and that radiological procedures involving the neck and head in patients with nodular goitre should be carried out with caution.