Ultrasonographic mass screening for thyroid carcinoma: a study in women scheduled to undergo a breast examination.

This study was carried out to clarify the sensitivity of ultrasonographic mass screening for thyroid carcinoma. Between December 1997 and July 1998, a total of 1401 subjects who were scheduled to undergo either a breast examination or a follow-up examination for breast cancer were enrolled in this study. Patients with thyroid nodules were classified into two groups according to their potential risk for malignancy based on the ultrasonographic findings. Ultrasonographic high-risk patients for thyroid cancer underwent an ultrasound guided fine-needle aspiration biopsy (FNAB) and were advised to undergo a thyroidectomy based on the FNAB results. The characteristics of the thyroid cancer patients detected by mass screening were then compared with those of 106 consecutive female patients with clinical thyroid cancer during the same period. Thyroid nodules were detected in 353 (25.2%) of the subjects, 94 (26.6%) of whom were placed in the high-risk group for thyroid cancer. Among the 94 high-risk patients, 43 underwent a thyroidectomy and 37 turned out to have thyroid carcinomas. The detection rate for thyroid cancer was 2.6% for all subjects. The tumor size was significantly smaller than that of the clinically detected cancer group (P < 0.05). Ultrasonographic mass screening for thyroid carcinoma in women who require breast examinations is thus considered to be effective for the detection of subclinical thyroid carcinoma.