Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Cancer. 2012 Feb 1;118(3):620-7. doi: 10.1002/cncr.26283. Epub 2011 Jun 29.
Medullary thyroid microcarcinomas (microMTCs) are medullary thyroid carcinomas (MTCs) that measure ≤1 cm in size for which there is a paucity of data on incidence, characteristics, and clinical significance.
Patients who had a diagnosis of microMTC were abstracted from the Surveillance, Epidemiology, and End Results database (1988-2007). The data were analyzed using chi-square tests, t tests, and log-rank tests; multivariate logistic regression was used to identify factors that were associated independently with lymph node metastases. Tests for diagnostic accuracy, including likelihood ratio tests and post-test probability tests, were computed to evaluate the size-specific likelihood of developing lymph node metastases among patients with microMTC.
In total, 310 patients had microMTC; its incidence increased during the study period (P(trend) = .033), and microMTC as a proportion of all MTCs increased by 39%. The mean tumor size was 5.7 mm. Thirty-one percent of tumors were multifocal, and 7.8% had extrathyroid extension. Lymph node metastases occurred in nearly 37% of patients who had any lymph nodes removed (65 of 176 patients). Nearly 20% of patients had regional disease, and 5% had distant metastases. The overall 10-year survival rates for patients with localized, regional, and distant disease stages were 96%, 87%, and 50%, respectively (P < .001). After adjustment, extrathyroid extension (odds ratio [OR], 41.9; P < .001) and tumor size (OR, 1.2; P = .008) retained an independent association with lymph node metastases. MTCs that measured ≤5 mm were associated with a probability of lymph node metastases of approximately 23%, and the probability increased for patients who had tumors >5 mm.
The current results indicated that microMTCs have significant rates of poor prognostic features known to impact the survival of patients with MTC. These microcarcinomas are an important clinical entity that requires comprehensive evaluation and surgical management.
甲状腺髓样微癌（microMTC）是指直径≤1cm 的甲状腺髓样癌（MTC），目前对于其发病率、特征和临床意义的数据较为缺乏。
从监测、流行病学和最终结果数据库（1988-2007 年）中提取诊断为甲状腺髓样微癌的患者资料。采用卡方检验、t 检验和对数秩检验进行数据分析；采用多因素逻辑回归分析确定与淋巴结转移独立相关的因素。计算似然比检验和后测概率检验等诊断准确性检验，以评估甲状腺髓样微癌患者发生淋巴结转移的大小特异性可能性。
共 310 例患者患有甲状腺髓样微癌；在研究期间其发病率增加（趋势检验 P=.033），甲状腺髓样微癌占所有 MTC 的比例增加了 39%。肿瘤的平均大小为 5.7mm。31%的肿瘤为多灶性，7.8%的肿瘤有甲状腺外侵犯。在切除任何淋巴结的 176 例患者中，近 37%的患者发生淋巴结转移（65 例）。近 20%的患者有区域疾病，5%的患者有远处转移。局部、区域和远处疾病阶段患者的 10 年总生存率分别为 96%、87%和 50%（P<0.001）。调整后，甲状腺外侵犯（优势比[OR]，41.9；P<0.001）和肿瘤大小（OR，1.2；P=0.008）与淋巴结转移仍有独立关联。直径≤5mm 的 MTC 与淋巴结转移的概率约为 23%，肿瘤直径>5mm 的患者发生淋巴结转移的概率增加。
目前的结果表明，甲状腺髓样微癌具有显著的不良预后特征，这些特征已知会影响 MTC 患者的生存。这些微癌是一种重要的临床实体，需要进行全面评估和手术治疗。
