Predicted and observed thyroid cancer incidence in Poland after year 1986

Chmielarczyk et al. analyzed thyroid cancer incidence in Poland between the years 1986 and 1994. Both for males and for females they found exponential increase of the directly standardized total incidence rates. The exponential growth could also be concluded for several age-specific rates in both sexes. Following the suggestion by Chmielarczyk et al., in this paper an attempt to verify their conclusions is undertaken. To this aim thyroid cancer incidence rates observed in Poland in 1995-2000 are compared with the predictions obtained from the models used by Chmielarczyk et al. to analyze the 1986-1994 data. The results of the comparison indicate that the predictions for the exponential growth model are consistent with the data observed in 1995-2000 for females. For males, however, an alternative possibility of a linear increase of incidence rates might also be applicable. To reach a more definite conclusion in this case, further follow up is needed.