Korean J Intern Med.  2010 Dec;25(4):408-414. 10.3904/kjim.2010.25.4.408.

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

• Lim DJ
• O JH
• Kim MH
• Kim JH
• Kwon HS
• Kim SH
• Kang MI
• Cha BY
• Lee KW
• Son HY

• KMID: 964722
• DOI: http://doi.org/10.3904/kjim.2010.25.4.408

Abstract

BACKGROUND/AIMS
Currently, 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.
METHODS
We 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.
RESULTS
Forty-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.
CONCLUSIONS
There 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.

Keyword

Iodine radioisotopes; Thyroglobulin; Thyroid neoplasms; Whole body scan

MeSH Terms

Adult
Aged
Female
Humans
Iodine Radioisotopes/pharmacokinetics/*therapeutic use
Male
Middle Aged
Thyroglobulin/*blood
Thyroid Neoplasms/blood/radionuclide imaging/*radiotherapy
*Whole Body Imaging