Background: The incidence of thyroid cancer (TC), a rare malignancy, has strongly risen in recent decades. Possible causes of this rise include increasing diagnostic activity, nuclear tests after World War II, and the Chernobyl disaster.
Aim: This article presents the time trends of TC incidence between 2003 and 2008 in Germany according to histological tumor type and sex, and provides a description of TC incidence according to districts (Kreise) and sex in Germany.
Methods: Data on persons newly diagnosed with thyroid cancer (ICD-10 code, C73) between 2003 and 2008 were obtained from the Center of Cancer Registry Data at the Robert Koch Institute. Official population and mortality data were used. Age-specific and age-standardized incidence rates (ASIR) were calculated according to sex and tumor histology.
Results: Between 2003 and 2008, the ASIR of TC rose from 2.7 to 3.4 (men) and from 6.5 to 8.9 (women) per 100,000 per year. This rise can be almost completely attributed to the rising incidence of papillary TC. The steepest rise in frequency was observed in TNM-T1 tumors. A positive north-south gradient of TC incidence was found.
Discussion: The cause of the marked rise of TC incidence in recent decades is unknown. The positive north-south gradient of the TC incidence may possibly be attributed in part to long-standing differences of iodine intake between different German regions.
Conclusion: An epidemiological study of the possible causes of the rising TC incidence and of the regional differences of TC incidence in Germany is recommended.