TgAb’s Change Trend and Degree of Decline Has Good Prognostic Value for Preoperative TgAb-Positive DTC Patients: A Retrospective Study in Southwest China

Abstract PurposeAntithyroglobulin antibody (TgAb) is a potential tumor marker for the detection of recurrence of DTC, but there are not sufficient data supporting its application in clinical work. Our study aimed at describing change trend of TgAb after surgery and finding the relationship between this trend and clinical outcome of DTC.MethodsWe reviewed clinical data of 583 patients initially diagnosed with thyroid malignancy and underwent total thyroidectomy (TTx) in our hospital in 2016. Finally, 21 preoperative TgAb-positive DTC patients with persistent disease were included in Group A, and 37 preoperative TgAb-positive DTC patients survived without disease were included in Group B. Various clinical indicators and TgAbs at different timepoints were compared between two groups.ResultsIn all 538 patients, 21.27% had preoperative TgAb positive (>115IU/mL), of which 16.94% survived with disease persistence/recurrence. Tumor, lymph node classification, and preoperative TgAb were significantly higher in Group A than B (P<0.05). TgAb of 23.81% patients in Group A became negative, and 89.19% in B. Compared with Group B, change trend of TgAb of Group A was more inclined stable or rising after surgery. Of patients with descending TgAb in Group A, their declines at first follow-up (40.75% vs 79.77%), the first year (76.67% vs 88.01%), the second year (80.00% vs 91.72%) after surgery were significantly lower than Group B (P<0.05). And the best cut-off values of three declines of TgAb for predicting clinical outcome were 43.32%, 72.81% and 84.36% respectively. Patients’ clinical outcome was significantly associated with tumor classification T1a (OR=145.661, 95%CI: 2.462-8619.550) and TgAb decline at first follow-up (OR=158.858, 95%CI: 7.440-3392.024).ConclusionsFor preoperative TgAb-positive DTC patients, stable or rising trend of TgAb after surgery or TgAb decline less than 43.43% before the RRA or 6 months after surgery may predict disease persistence/recurrence.