Background: The incidence of thyroid cancer in Korea has increased by about 25 % every year for the past 10 years. This increase is largely due to a rising incidence in papillary thyroid cancer, which is associated with an overdiagnosis of small tumors that may never become clinically significant. This study was conducted to explore Korean women's understanding of overdiagnosis and to investigate changes in screening intention in response to overdiagnosis information.
Methods: Focus group interviews were conducted among women of ages 30-69 years, who are commonly targeted in Korea for cancer screening. Women were divided into four groups according to thyroid cancer screening history and history of thyroid disease. Of 51 women who were contacted, 29 (57 %) participated in the interviews.
Results: Prior awareness of thyroid cancer overdiagnosis was minimal. When informed about the risks of overdiagnosis, the participants were often surprised. Overcoming initial malcontent, many women remained skeptic about overdiagnosis and trusted in the advice of their physicians. Meanwhile, some of the study participants found explanations of overdiagnosis difficult to understand. Further, hearing about the risks of overdiagnosis had limited impact on the participants' attitudes and intentions to undergo thyroid cancer screening, as many women expressed willingness to undergoing continued screening in the future.
Conclusion: A large majority of Korean women eligible for and had undergone thyroid cancer screening were unaware of the potential for overdiagnosis. Nevertheless, overdiagnosis information generally had little impact on their beliefs about thyroid cancer screening and their intentions to undergo future screening. Further research is needed to determine whether these findings could be generalized to the wider Korean population.