Nucl Med Mol Imaging.  2018 Aug;52(4):287-292. 10.1007/s13139-018-0528-7.

Response Prediction of Altered Thyroglobulin Levels After Radioactive Iodine Therapy Aided by Recombinant Human Thyrotropin in Patients with Differentiated Thyroid Cancer

• Song M
• Jeon S
• Kang SR
• Jabin Z
• Yoo SW
• Min JJ
• Bom HS
• Cho SG
• Kim J
• Song HC
• Kwon SY

• KMID: 2418992
• DOI: http://doi.org/10.1007/s13139-018-0528-7

Abstract

PURPOSE
Thyroglobulin (Tg) may be released from damaged residual thyroid tissues after radioactive iodine (RAI) therapy in patients with differentiated thyroid carcinoma (DTC). We investigated whether altered levels of serum Tg after recombinant human thyrotropin (rhTSH)-aided RAI therapy could be a prognostic marker in patients with DTC.
METHODS
We evaluated 68 patients who underwent RAI therapy after total thyroidectomy. Serum Tg levels were measured just before RAI administration (D0Tg) and 7 days after RAI therapy (D7Tg). Patients with a D0Tg level greater than 2.0 ng/mL were excluded to more precisely evaluate the injury effect of RAI in small remnant tissues. The ratioTg was defined as the D7Tg level divided by that on D0Tg. The therapeutic responses were classified as acceptable or non-acceptable. Finally, we investigated which clinicopathologic parameters were associated with therapeutic response.
RESULTS
At the follow-up examination, an acceptable response was observed in 50 patients (73.5%). Univariate analysis revealed significant differences in N stage (P = 0.003) and ratioTg (acceptable vs. non-acceptable responses, 21.9 ± 33.6 vs. 3.8 ± 6.5; P = 0.006). In multivariate analysis, only ratioTg significantly predicted an acceptable response (odds ratio 1.104; 95% confidence interval 1.005-1.213; P = 0.040). A ratioTg above 3.5 predicted an acceptable response with a sensitivity of 66.0%, specificity of 83.3%, and accuracy of 70.6% (area under the curve = 0.718; P = 0.006).
CONCLUSIONS
Altered levels of serum Tg after RAI therapy, calculated as the ratioTg (D7Tg/D0Tg), significantly predicted an acceptable response in patients with DTC.

Keyword

Differentiated thyroid carcinoma; Radioactive iodine therapy; Recombinant human thyrotropin; Thyroglobulin; Therapeutic response

MeSH Terms

Follow-Up Studies
Humans*
Iodine*
Multivariate Analysis
Sensitivity and Specificity
Thyroglobulin*
Thyroid Gland*
Thyroid Neoplasms*
Thyroidectomy
Thyrotropin*
Iodine
Thyroglobulin
Thyrotropin