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

Area of Science:

• Oncology
• Thoracic Surgery
• Pathology

Background:

• Thymic malignancies are rare tumors with variable prognosis.
• Lymph node metastasis is a critical prognostic factor in thymic malignancies.
• Accurate staging is essential for treatment planning and patient outcomes.

Purpose of the Study:

• To investigate the incidence and pattern of lymph node metastases in thymic malignancies.
• To compare findings with previous retrospective data.
• To identify risk factors for lymph node involvement.

Main Methods:

• A multicenter prospective observational trial was conducted by the Chinese Alliance for Research in Thymomas (ChART).
• Data from 275 treatment-naive patients with thymic tumors were prospectively collected.
• Intentional lymph node dissection was performed, and results were compared to a ChART retrospective study.

Main Results:

• Lymph node metastasis was detected in 5.5% of patients (15/275), with higher rates in thymic carcinomas (25%) and neuroendocrine tumors (50%).
• Nodal metastasis incidence increased with tumor T category (T1: 2.7%, T3: 18.4%, T4: 50%) and aggressive histology (B3, carcinoma, neuroendocrine).
• Intentional dissection revealed higher nodal involvement (5.5%) compared to the retrospective study (2.2%), with metastasis often found in N1 and N2 nodes.

Conclusions:

• Lymph node involvement in thymic malignancies is more frequent than previously recognized, especially in advanced or aggressive tumors.
• Intentional lymph node dissection enhances detection rates and improves staging accuracy.
• Systemic dissection of N1 and N2 nodes is recommended for high-risk patients to ensure accurate staging.