갑상선분화암 추적관찰에 있어 갑상선호르몬 중단에 따른 대사적 변화 및 호르몬 중단 필요성에 대한 고찰

다국어 초록 (Multilingual Abstract)

Introduction: After total thyroidectomy, differentiated thyroid cancer (DTC) patients have to undergo levothyroxine (LT4) withdrawal for measurement of TSH stimulated thyroglobulin (Tg) and 131I whole-body scan to evaluate residual or recurrent disease. It is well known that hypothyroidism can affect various target organs and tissues. But, there are a few studies looking into the effects of LT4 withdrawal in DTC patients in terms of metabolic parameters. Furthermore, sensitivity of other imaging modalities for detection of recurred DTC were markedly improved and false negative rate of TSH stimulated Tg was also reported. Therefore, present study was aim to investigate the metabolic changes by short-term hypothyroidism induced by LT4 withdrawal and to discuss the necessity of LT4 withdrawal.
Methods: The patients were included who underwent high dose radioactive iodine (RAI) therapy due to recurred or remnant DTC after total thyroidectomy and post-operative RAI therapy, from January 2000 to October 2012 at Chonbuk national university hospital. Total 84 patients were reviewed by medical record and laboratory data, retrospectively. Body weight, body mass index (BMI), serum sodium, liver function test (AST, ALT), lipid profiles (total cholesterol, triglyceride, LDL cholesterol), serum creatinine, protein, albumin, and glucose levels were determined both before and after LT4 withdrawal. And false negative rate of TSH stimulated Tg and effect of anti-Tg antibody on measurement of Tg were evaluated.
Results: There was no significant change in body weight, BMI, sodium, protein, albumin and glucose after LT4 withdrawal. But there were statistically significant increases in AST, ALT, total cholesterol, triglyceride, LDL cholesterol and serum creatinine after LT4 withdrawal (p<0.001). 29 of 84 patients showed TSH stimulated Tg level below 2ng/ml after LT4 withdrawal despite of remnant or recurred disease detected in imaging modalities (false negative rate : 34.52%). Only 2 patients were detect recurred or remnant DTC by TSH stimulated Tg. Positivity of anti-Tg antibody was 35.71% (30 of 84 patients). Among them, the patients who showed serum Tg level below 2ng/ml was 63.33% (19 of 30 patients).
Conclusions: Short-term hypothyroidism induced by LT4 withdrawal in DTC patients seriously affects multiple organs and systems. In this study, short-term hypothyroidism was associated with significant increases in risk factors for atherosclerosis, renal and hepatic dysfunctions. Furthermore, TSH stimulated Tg showed relatively low sensitivity compared to other imaging modalities. Therefore, alternative methods including specific imaging modalities or use of recombinant human TSH instead of LT4 withdrawal should be considered, especially patients with high risk of iatrogenic hypothyroidism.

목차 (Table of Contents)

• 1. Abstract 1
• 2. 서론 4
• 3. 대상 및 방법 6
• 4. 결과 8
• 5. 고찰 11
• 6. 참고문헌 15
• 7. 표 및 그림 18