Mammography and the risk of thyroid and hematological cancers: a nationwide population-based study.

To investigate the association between thyroid cancer as well as the most radiosensitive hematological cancers and radiation exposure from mammography. This study used information from a random sample of two million persons enrolled in the nationally representative Taiwan National Health Insurance (NHI) Research Database. The exposed group was composed of women aged 18-65 who had undergone diagnostic mammography between 2000 and 2007. The nonexposed control group was composed of women in the NHI database who had never undergone diagnostic mammography. There were 25,362 women in the exposed group and 203,317 women in the nonexposed group. After adjusting for age and comorbidities, the patients who had been exposed to radiation from mammography did not have a significantly higher risk of developing thyroid cancer and hematological cancers (adjusted HR, 1.201; 95% CI, 0.813-1.774 for thyroid cancer and adjusted HR, 1.228; 95% CI, 0.838-1.800 for hematological cancers). The scattered radiation dose delivered by mammography should be cautiously handled, but no additional concerns about the risk of thyroid cancer developing malignancy should be emphasized.