Background: We previously demonstrated comparable thyroid remnant ablation rates in postoperative low-risk thyroid cancer patients prepared for administration of 3.7GBq 131I (100 mCi) after recombinant human (rh) TSH during T4 (L-T4) therapy vs. withholding L-T4 (euthyroid vs. hypothyroid groups). We now compared the outcomes of these patients 3.7 yr later. Patients and Methods: Fifty-one of the 63 original patients (28 euthyroid, 23 hypothyroid) participated. Forty-eight received rhTSH and serum thyroglobulin (Tg) sampling. A 131I whole-body scanwasperformed in43patients,andsuccessful ablationwasdefined by criteriafromthe previous study. Based on the criterion of uptake less than 0.1% in thyroid bed, 100% (43 of 43) remained ablated. When no visible uptake instead was used, five patients (four euthyroid, one hypothyroid) had minimal visible activity. When the TSH-stimulated Tg criterion was used, only two of 45 (one euthyroid, one hypothyroid) had a stimulated Tg level greater than 2 ng/ml. Results: No patient in either group died, and no patient declared disease free had sustained tumor recurrence. Nine (four euthyroid, five hypothyroid) had received additional 131I between the original and current studies due to detectable Tg or imaging evidence of disease; with follow-up, all now had a negative rhTSH-stimulated whole-body scan and seven (three euthyroid, four hypothyroid) had a stimulated serum Tg less than 2 ng/ml. Conclusions: In conclusion, after a median 3.7 yr, low-risk thyroid cancer patients prepared for postoperative remnant ablation either with rhTSH or after L-T4 withdrawal were confirmed to have had their thyroid remnants ablated and to have comparable rates of tumor recurrence and persistence.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical