Ultrasonographic screening for occult thyroid cancer.

Background: It has been shown that occult thyroid carcinoma can be identified in about 10% of thyroid glands in autopsy. The purpose of this study was to evaluate the prevalence of asymptomatic thyroid carcinoma in the Hong Kong Chinese population by ultrasonographic screening.

Methods: Volunteer subjects without symptoms of thyroid disease were recruited for ultrasonographic screening for thyroid cancer. A total of 1140 subjects were recruited in this study.

Results: Thyroid nodules were found in 45% subjects (511 of 1140); the mean age was 48 years. Ultrasonographic-guided aspiration cytology was performed in 258 subjects. Twenty-six subjects (2.3%) had cytologic findings suspicious of malignancy. Fourteen subjects (1.2%) had pathologic diagnosis of thyroid cancer, including 13 papillary carcinomas and 1 follicular carcinoma.

Conclusion: A high incidence of occult thyroid cancer could be identified on ultrasonographic screening. Subjects could benefit with early diagnosis with either early intervention or close monitoring.