1986 Volume 47 Issue 10 Pages 1191-1197
A mass screening for thyroid cancer was performed in Gunma prefecture from 1980 to March 1985, in co-operation with the Gunma Cancer Society. In this survey the total number of subjects was 91, 787 cases (54, 625 actual persons). Thyroid abnormalities at the first screening were found in 4.6% of the total and a second examination was required in 2.4%.
Histologically, 133 cases were found to have thyroid carcinoma (papillary carcinoma in 117 cases, follicular carcinoma in 15, and medullary carcinoma in one) and the detection rate was 0.14% (0.24% for actual persons). The detection rate in the initial screening was higher (0.18%) than that (0.09%) in the subsequent screenings. 109 cases (82.0%) were largely symptomless at the time of screening. Tumor size was smaller than 2.0cm in diameter in 87 cases (65.5%) and microcancer (<1.0cm) was found in 22.6%. Cancers detected by screening were found at a significantly earlier stage compared with cancers of outpatients as regards lymph node metastasis and extrathyroidal invasion. The prognosis was very good and 130 cases remained disease-free. Exceptions were one case each of recurrence from lymph node and residual thyroid and one accidental death. Mass screening is useful for the early discovery and treatment of thyroid cancer and should be used more commonly.