Clinical Significance of Observation without Repeated Radioiodine Therapy in Differentiated Thyroid Carcinoma Patients with Positive Surveillance Whole-Body Scans and Negative Thyroglobulin

Abstract

Background/AimsCurrently, there is no consensus on the necessity of repeated radioiodine therapy (RAI) in patients who show iodine uptake in the thyroid bed on a diagnostic whole-body scan (DxWBS) despite undetectable thyroglobulin (Tg) levels after remnant ablation. The present study investigated the clinical outcomes of scan-positive, Tg-negative patients (WBS+Tg-) who did or did not receive additional RAI.MethodsWe retrospectively reviewed 389 differentiated thyroid carcinoma patients who underwent a total thyroidectomy and received high-dose RAI from January 2003 through December 2005. The patients were classified according to surveillance DxWBS findings and TSH-stimulated Tg levels 6 to 12 months after the initial RAI.ResultsForty-four of the 389 patients (11.3%) showed thyroid bed uptake on a DxWBS despite negative Tg levels (WBS+Tg-). There was no difference in clinical and pathological parameters between WBS+Tg- and WBS-Tg- patients, except for an increased frequency of thyroiditis in the WBS+Tg- group. Among the 44 WBS+Tg- patients, 27 subjects were treated with additional RAI; 25 subjects showed no uptake in subsequent DxWBS. Two patients were evaluated only by ultrasonography (US) and displayed no persistent/recurrent disease. The other 17 patients received no further RAI; Eight patients and two patients showed no uptake and persistent uptake, respectively, on subsequent DxWBS. Six patients presented negative subsequent US findings, and one was lost to follow-up. Over the course of 53.2 ± 10.1 months, recurrence/persistence was suspicious in two patients in the treatment group.ConclusionsThere were no remarkable differences in clinical outcomes between observation and treatment groups of WBS+Tg- patients. Observation without repeated RAI may be an alternative management option for WBS+Tg- patients.

Clinical implications of anti-thyroglobulin antibody measurement before surgery in thyroid cancer

“…We previously reported that in DTC patients who previously had total thyroidectomy and high-dose RI remnant ablation, thyroid bed RI uptake at the postoperative 6- to 12-month whole-body scan showed a close association with higher TgAb levels, compared to no thyroid bed uptake [ 44 ]. Dewi et al [ 45 ] also reported that higher post-RI TgAb levels were significantly correlated with unsuccessful RI therapy (OR, 5.379; p = 0.007), which indicates that TgAb could serve as a surrogate marker for successful RI.…”

Correlation of Clinicopathological Features and Expression of Molecular Markers With Prognosis After 131I Treatment of Differentiated Thyroid Carcinoma

“…After radioiodine therapy, if there was no evidence of disease ( 131 I whole-body scan negative, stimulated thyroglobulin (Tg) Ͻ2 g/L, and absence of anti-Tg antibody), the patient was considered to be cured. A positive whole-body scan and/or stimulated Tg levels above 5 to 10 g/L were considered to indicate the presence of residual or recurrent tumor, 14 and the patients were considered to be noncured. Clinical history, pathologic findings, radioiodine therapy, and follow-up information were collected.…”

Incidence and implications of negative serum thyroglobulin but positive I‐131 whole‐body scans in patients with well‐differentiated thyroid cancer prepared with rhTSH or thyroid hormone withdrawal

“…Occasionally, during follow‐up of thyroid cancer patients, clinicians encounter the combination of a positive stimulated post‐therapy or diagnostic whole‐body I‐131 scan but negative (undetectable) serum Tg/TgAb levels 6–8 . The precise frequency and implications of such a scenario, however, remain unclear.…”