Clinical outcomes of persistent radioiodine uptake in the neck shown by diagnostic whole body scan in patients with differentiated thyroid carcinoma after initial surgery and remnant ablation.
OBJECTIVE
To evaluate the clinical outcomes of persistent radioiodine uptake (RAIU) in the neck by diagnostic whole body scan (DxWBS) after initial therapy and the efficacy of the second ablation in patients with differentiated thyroid carcinoma (DTC).


METHODS
Patients with DTC who underwent bilateral surgery and high-dose remnant ablation between 2000 and 2004 were included. Patients with elevated serum stimulated thyroglobulin (sTg) or extensive lateral neck lymph node involvement at initial surgery underwent a second ablation, and patients with undetectable sTg or in very low-risk groups were observed.


RESULTS
Among 572 patients, 25 had persistent RAIU in the neck at first DxWBS. After a median 65.7 months of follow-up, five of these patients (20%) had persistent disease, whereas another 20 patients had no abnormal findings by ultrasonography (US) or other imaging modalities. Seven of 20 patients underwent second ablation and 13 were observed. RAIU disappeared spontaneously in about half of the patients in the observation group. There were no significant between-group differences in change of RAIU at follow-up DxWBS (P = 0.62). Serum sTg decreased and eventually disappeared over a few years in both groups. Ablation failure was not an independent risk factor for recurrence (P = 0.169).


CONCLUSIONS
Neck US and serum sTg, but not DxWBS, were useful diagnostic tools during follow-up of patients with persistent uptake in the neck at DxWBS. A second ablation was not necessary when neck US showed no evidence of disease, especially in patients with very low sTg concentration.
Kim
Eui Young
EY
Department of Endocrinology & Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul 138-736, Korea.
Kim
Won Gu
WG
Kim
Won Bae
WB
Kim
Tae Yong
TY
Ryu
Jin-Sook
JS
Gong
Gyungyub
G
Yoon
Jong Ho
JH
Hong
Suck Joon
SJ
Lee
Jeong Hyun
JH
Baek
Jung Hwan
JH
Shong
Young Kee
YK
D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D002454:Cell Differentiation; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck; D018365:Neoplasm, Residual; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D051598:Whole Body Imaging; D055815:Young Adult
D007457:Iodine Radioisotopes