OBJECTIVETo investigate the change of thyroglobulin antibodies (TgAb) after the application of selenious yeast tablet (SYT) in differentiated thyroid cancer (DTC) patients with positive TgAb (>115 U/ml).

METHODSWe enrolled 41 DTC patients with positive TgAb who had undergone total thyroidectomy and subsequent ¹³¹I therapy as well as applied SYT in group 1 (G1). Patients with an interval of more than 6 months between SYT use and ¹³¹I therapy or with repeated TgAb measurements before the use of SYTs were divided into group 2 (G2) and group 3 (G3), respectively. Changes in TgAb after application of SYT in both G1 and G2 were observed and analyzed by rank sum test. Comparison of TgAb gradient over certain time before and after the application was analyzed by t-test.

RESULTSThe proportions of patients with decreased or elevated TgAb were 85.4% and 14.6% in G1 and 90.9% and 9.1% in G2, respectively. Compared with the previous TgAb levels, TgAb decreased significantly after the application of SYT in either G1 (P=0.000) or G2(P=0.003). In G3, the TgAb level rose by 5.6% every month before applying SYT and fell 8.3% every month after the application (P=0.086).

CONCLUSIONApplication of SYT in DTC patients with positive TgAb can effectively decrease the TgAb level.