Marturano I, Russo M, Spadaro A, Latina A, Malandrino P, Regalbuto C
Endocrinology, Department of Sperimental Clinical Medicine, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95122, Catania, Italy,
J Endocrinol Invest. 2015 Sep;38(9):1017-22. doi: 10.1007/s40618-015-0318-3. Epub 2015 Jun 13.
After thyroidectomy for thyroid cancer, patients often withdraw L-T4 for diagnostic or therapeutic purposes, showing signs and symptoms of hypothyroidism. A slighter hypothyroidism (reducing L-T4 to one-half) has been proposed to limit these inconveniences. We evaluated half-dose L-T4 protocol, in comparison to conventional L-T4 withdrawal, in terms of effectiveness and improvement of clinical and biochemical disorders.
We randomized 55 thyroid cancer patients into two groups: 29 patients underwent 5 weeks of half-dose of previous L-T4 treatment (HD group); 26 patients replaced L-T4 with L-T3 for 3 weeks followed by 2 weeks of withdrawal (TW group). Clinical features (Zulewsky clinical score) and biochemical parameters (lipids, liver, and muscle enzymes) were evaluated in all patients at baseline and after 5 weeks.
Total cholesterol, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase increased at 5 weeks in both groups, but significantly more in TW, but no difference was found by clinical score. Patients who achieved the thyroid-stimulating hormone (TSH) target value (25 µU/ml) were 92.3% in TW group and 48.3% in HD group (p < 0.001). In the HD group, only basal TSH statistically correlated with the achievement of the TSH target. Receiver operating characteristic curves indicated that a basal TSH ≥0.52 μU/ml is required to reach an adequate TSH level.
Half-dose L-T4 protocol, compared to conventional L-T4 withdrawal, is associated with less biochemical disorders but no significant clinical advantage. Therefore, the half-dose protocol reaches an adequate TSH target in 48.3% of patients and is not effective unless basal serum TSH is ≥0.52 μU/ml.
甲状腺癌患者在甲状腺切除术后，常因诊断或治疗目的停用左甲状腺素（L-T4），出现甲状腺功能减退的体征和症状。有人提出采用轻度甲状腺功能减退（将L-T4剂量减半）来减少这些不便。我们评估了半剂量L-T4方案与传统L-T4停药方案相比，在临床和生化紊乱的有效性及改善方面的情况。
我们将55例甲状腺癌患者随机分为两组：29例患者接受5周前L-T4剂量减半的治疗（HD组）；26例患者先用L-T3替代L-T4治疗3周，然后停药2周（TW组）。在基线和5周后对所有患者评估临床特征（祖莱夫斯基临床评分）和生化参数（血脂、肝脏和肌肉酶）。
两组患者在5周时总胆固醇、肌酸激酶、乳酸脱氢酶、天冬氨酸转氨酶和丙氨酸转氨酶均升高，但TW组升高更显著，而临床评分无差异。TW组达到促甲状腺激素（TSH）目标值（25 μU/ml）的患者为92.3%，HD组为48.3%（p<0.001）。在HD组，仅基础TSH与TSH目标值的达成有统计学相关性。受试者工作特征曲线表明，基础TSH≥0.52 μU/ml才能达到足够的TSH水平。
与传统L-T4停药方案相比，半剂量L-T4方案的生化紊乱较少，但无显著临床优势。因此，半剂量方案在48.3%的患者中能达到足够的TSH目标，除非基础血清TSH≥0.52 μU/ml，否则该方案无效。
