Thyroid autoantibodies and differentiated thyroid cancer: revue of 662 cases

The incidence of thyroid autoantibodies is clearly increased in patients with differentiated thyroid cancer. The aim of this study was to re-evaluate frequency and evolution of anti-thyroglobulin and anti-microsomal (anti-peroxidase) autoantibodies in 662 patients with thyroid carcinoma treated with 131 radioiodine. Ours results obtained with 'classical' methods confirmed others earlier reports. When using more sensitive methods to detect thyroglobulin antibodies we obtained an increase in positive results and a more frequent association with anti-microsomal antibodies. Antibodies became undetectable with a variable period, ranging from a few months to 13 years in one case. If we suppose that the disappearance of antibodies is linked to the thyroid tissue disappearance, thyroid cancer follow up ought to include anti-thyroglobulin and anti-peroxidase antibodies, both directed against thyroid antigens. A decrease of both antibodies seems to indicate a favorable prognostic factor whereas an increase may suggest relapse. (author)