胸腺恶性肿瘤淋巴结转移的多中心前瞻性观察研究

胸腺恶性肿瘤淋巴结转移的多中心前瞻性观察研究。

Lymph node metastasis in thymic malignancies: A Chinese multicenter prospective observational study.

目的：探讨胸腺恶性肿瘤淋巴结转移的发生率及规律。

方法：由中国胸腺瘤研究联盟（ChART）进行的多中心前瞻性淋巴结清扫观察试验。前瞻性收集未经预处理的胸腺肿瘤患者的资料。然后将这项前瞻性研究的结果与先前报告的ChART回顾性研究的结果进行比较。

结果：275例患者中，转移灶41个（3.04%），转移灶15个（5.5%）。胸腺瘤淋巴结转移率为2.1%（5/238），胸腺癌淋巴结转移率为25%（6/24），神经内分泌肿瘤淋巴结转移率为50%（4/8）（P<0.001）。T1～T4类肿瘤的淋巴结转移率T1为2.7%（6/222），T2为7.7%（1/13），T3为18.4%（7/38），T4为50%（1/2）（P<0.001）。尽管两组在肿瘤分期和组织学方面具有可比性，但与ChART回顾性研究相比，淋巴结受累率明显增高（5.5%对2.2%；P=0.002）。13例（86.7%）N1淋巴结转移，8例（53.3%）N2淋巴结转移，6例（40%）同时有N1/N2病变，6例（40%）有多部位转移。根据世界卫生组织组织学分类和国际癌症控制联盟T分类，将患者分为T1-2和a-B2型疾病的低风险组（1/192；0.5%）和T3及以上或B3及以上肿瘤淋巴结转移的高风险组（14/83；16.9%）（P<0.001）。经多因素分析，B3型/胸腺癌/神经内分泌肿瘤，T3或T3以上，N2淋巴结清扫预示淋巴结转移的可能性更大。

结论：胸腺恶性肿瘤中淋巴结受累较以往更为常见，尤其是组织学上具有侵袭性和T分期的肿瘤。目的性淋巴结清扫增加了淋巴结受累的发现，提高了分期的准确性。在选定的高危患者中，应考虑对N1和N2淋巴结进行系统性切除，以获得准确的肿瘤分期。

Abstract

OBJECTIVES: To study the incidence and pattern of lymph node metastases in thymic malignancies.

METHODS: This multicenter prospective observational trial with intentional lymph node dissection was carried out by the Chinese Alliance for Research in Thymomas (ChART). Data on patients with thymic tumors without pretreatment were collected prospectively. Results from this prospective study were then compared with those from a previously reported ChART retrospective study.

RESULTS: Among 275 patients, metastasis was detected in 41 nodes (3.04%) in 15 patients (5.5%). The rate of lymph node metastasis was 2.1% (5/238) in patients with thymomas, 25% (6/24) in those with thymic carcinomas, and 50% (4/8) in those with neuroendocrine tumors (P < .001). The rate of lymph node metastasis in category T1 to T4 tumors was 2.7% (6/222) in T1, 7.7% (1/13) in T2, 18.4% (7/38) in T3, and 50% (1/2) in T4 (P < .001). Nodal involvement was significantly higher compared with the ChART retrospective study (5.5% vs 2.2%; P = .002), although the 2 groups were comparable in terms of tumor stage and histology. Metastasis was found in N1 nodes in 13 patients (86.7%) and in N2 nodes in 8 patients (53.3%); 6 patients (40%) had simultaneous N1/N2 diseases and 6 (40%) had multistation involvement. Based on World Health Organization histological classification and Union for International Cancer Control T category, patients were divided into a low-risk group (1/192; 0.5%) with T1-2 and type A-B2 diseases and a high-risk group (14/83; 16.9%) of category T3 and above or histology B3 and above tumors for nodal metastasis (P < .001). On multivariate analysis, type B3/thymic carcinoma/neuroendocrine tumors, category T3 or above, and N2 dissection predicted a greater likelihood of finding nodal metastasis.

CONCLUSIONS: Lymph node involvement in thymic malignancies is more common than previously recognized, especially in tumors with aggressive histology and advanced T category. Intentional lymph node dissection increases the detection of nodal involvement and improves accuracy of staging. In selected high-risk patients, systemic dissection of both N1and N2 nodes should be considered for accurate tumor staging.