PT  - JOURNAL ARTICLE
AU  - Choi, Yun Jung
AU  - Cho, Arthur
AU  - Lee, Jae-Hoon
AU  - Cho, Ho Jin
AU  - Seo, Hyojung
AU  - Yun, Mijin
AU  - Lee, Jong Doo
AU  - Kang, Won Jun
TI  - Optimal TSH level for serum thyroglobulin to predict disease status in thyroid cancer
DP  - 2010 May 01
TA  - Journal of Nuclear Medicine
PG  - 1602--1602
VI  - 51
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/51/supplement_2/1602.short
4100  - http://jnm.snmjournals.org/content/51/supplement_2/1602.full
SO  - J Nucl Med2010 May 01; 51
AB  - 1602 Objectives Serum thyroglobulin (Tg) level is a standard method to detect recurrent thyroid cancer, and its level is dependent upon serum TSH level. To achieve adequate TSH level over 30 U/ml, thyroid hormone withdrawal (THW) or recombinant human TSH injection is performed. However, impact of TSH on Tg level at the range over 30 U/ml is unclear. We evaluated correlation of serum TSH level and serum Tg level in patients with thyroid cancer. Methods A total of 160 differentiated thyroid cancer patients scheduled for high dose radioactive iodine therapy were enrolled in a prospective manner (mean age 48 yr, M:F=45:115). For preparation of therapy, patients were instructed to discontinue thyroxin at 4 weeks before therapy. At 3 weeks and 4 weeks after withdrawal of thyroxin, serum TSH, serum Tg level, and serum Tg Ab level were measured. Whole body iodine scan was acquired at 3 days and 7 days after treatment. Results TSH level increased from 65.1±23.9 at 3 weeks to 80.1±16.6 at 4 weeks. At 3 weeks after THW, 130 patients achieved therapeutic TSH level over 30 U/ml, and TSH level increased from 70.8±19.4 to 83.2±13.6. Among 30 patients with TSH level under 30 U/ml, 18 achieved TSH level at 4 weeks (TSH level, 23.8±6.8 to 57.7±20.4). Remaining 12 patients underwent rhTSH administration (TSH level, 11.8±7.5 to 88.2±13.6). Tg level increased from 80.0±148.8 at 3 weeks to 89.4±155.2 at 4 weeks. Tg Ab level was 116.7±395.2 at 3 weeks and 114.7±383.5 at 4 weeks. Six patients showed Tg level under 2 U/ml at 3 weeks and over 2 U/ml at 4 weeks (Tg level, 1.62±0.32 to 3.01±1.2) On this group, TSH level was 63.4±16.8 at 3 weeks and 82.1±9.2 at 4 weeks, while Tg Ab was 8.27±3.81 at 3 weeks and 8.34±5.0. Conclusions We evaluated correlation of serum TSH level and serum Tg level at different time points. About 81% patients achieved therapeutic TSH level at 3 weeks after THW. Tg level showed positive correlation with TSH level. In conclusion, 3.75 % of patients converted from Tg negative to Tg positive according to THS increase