Unexplained Hyperthyroglobulinemia in Differentiated Thyroid Cancer Patients as an Indication for Radioiodine Adjuvant Therapy: A Prospective Multicenter Study

Abstract

Background: The management for totally thyroidectomized differentiated thyroid cancer (TT-DTC) patients with unexplained hyperthyroglobulinemia remains indeterminate due to evidence scarcity. This multicenter study aimed at prospectively evaluating the response to radioiodine (131 I) adjuvant therapy (RAT) and its potential role in risk stratification and causal clarification. Methods: TT-DTC patients with stimulated serum thyroglobulin (Tgoff) levels > 10 ng/mL but no structurally evident disease were consecutively enrolled in five tertiary care institutions. After the administration of 5.55 GBq of 131 I, the risk of presence of persistent/recurrent/metastatic DTC (prmDTC) was compared to that before RAT. The causes of hyperthyroglobulinemia were explored and the response to RAT was assessed 6-12 months post RAT. The change in suppressed thyroglobulin (Tgon) level was reported. Results: A cohort of 254 subjects with a median Tgoff of 27.1 ng/mL was enrolled for the analyses. Immediately after RAT, low-, intermediate-, and high-risk were identified in 5.9%, 88.6%, and 5.5% patients, respectively, with no significant difference in risk stratification compared with that before RAT (p = 0.952). During the follow-up (median, 10.6 months), hyperthyroglobulinemia was ultimately attributed to thyroid remnant, biochemical disease, and structural/functional disease in 17.3%, 54.3%, and 28.3% of subjects, respectively. In addition, excellent, indeterminate, biochemical incomplete, and structural/functional incomplete responses were achieved in 18.1%, 27.2%, 36.2%, and

CACA guidelines for holistic integrative management of thyroid cancer

“…Adjuvant therapy Adjuvant therapy is mainly used in patients without confirmed imaging evidence, including those with (1) elevated postoperative serum Tg or indeterminate biochemical response mismatched with DxWBS suggesting thyroid remnants; and (2) clinically suspetecd postoperative residual disease without definitive imaging evidence [130]. The possibility of successful removal by upfront treatment (such as surgery) cannot be excluded.…”

Clinical outcome and influencing factors for postoperative papillary thyroid cancer with unexplained elevated Tg prior 131I therapy

“…With more than 5-10 years of follow-up, 56-68% of patients with BIR presented with no evidence of disease at the nal follow-up and the risk of developing structural disease was reported as 8-17% [4][5][6]. Cheng et al [7] analyzed DTC patients after total thyroidectomy with unexplained preablative stimulated thyroglobulin (ps-Tg) > 10ng/mL without structural disease. This study assessed the short-term response to RAT and its potential role in risk strati cation and causal clari cation.…”

Radioiodine adjuvant therapy in differentiated thyroid cancer: An update and reconsideration

“…A meta-analysis involving 3947 DTC patients in fifteen studies demonstrated that DTC patients with ps-Tg levels less than 10 ng/ml without the influence of TgAb levels are ideally linked to a better prognosis through RAT, and merely 6% of those patients had persistent disease ( 26 ). In a multicentre prospective study, 80% DTC patients with ps-Tg levels ≥10 ng/ml, as well as worse clinicopathological features, kept in a non-structurally incomplete response after 5.55 GBq (150 mCi) of RAT, with a median follow-up of 10.6 months ( 30 ). Therefore, higher ps-Tg levels (≥10 or 30 ng/ml) which can reflect unsatisfying real-time postoperative disease status, are likely to guide the consideration of RAT ( 26 , 29 ).…”