Nodal dissection in thymic surgery: a narrative review of the evolution of practice and evidence in the era of the 9th edition TNM classification (2000-2025).

Background and Objective: Lymph node dissection (LND) for thymic epithelial tumors (TETs) has been performed inconsistently due to guidance from heterogeneous definitions of "intentional" versus "incidental" nodal dissection. Persistent variability in the recommendations of the International Thymic Malignancy Interest Group (ITMIG) and the International Association for the Study of Lung Cancer (IASLC), there remains equipoise among surgical teams on nodal dissection during thymic resection. The objective of this narrative review is to synthesize the contemporary evidence on the indications, optimal extent, technical conduct, and oncologic implications of LND in TETs, and to translate that evidence into a pragmatic, risk-adapted protocol to guide clinical practice. Methods: We performed a focused narrative review covering January 2000 to March 2025. PubMed/MEDLINE, the Cochrane Library, Embase, Scopus, and Web of Science were searched using a Boolean string combining "thymoma OR thymic carcinoma OR thymic neuroendocrine tumor OR thymic epithelial tumor" with "lymphadenectomy OR lymph node dissection OR nodal metastasis". The search was supplemented by the Japanese Association for Research in the Thymus (JART), European Society of Thoracic Surgeons (ESTS), and Chinese Alliance for Research in Thymoma (ChART) database publications. Inclusion criteria: adult human studies; English; ≥20 patients with TET reporting nodal yield, incidence, or outcomes. Thirty-two studies were retained. Key Content and Findings: Nodal incidence varied predictably with histology and stage: <2% in World Health Organization (WHO) type A/AB/B1; 5-15% in B2/B3; 25-32% in thymic carcinoma; 40-50% in thymic neuroendocrine tumor (NET). Tumor size >5 cm, T3-T4 disease, and high-grade histology were independent predictors. Skip metastasis to N2 occurred in 8-10% of thymic carcinomas, most commonly the right paratracheal (4R). LND improved staging accuracy but did not independently improve survival in propensity-matched analyses, reflecting confounding by adjuvant therapy and the role of nodal status as a marker of disease biology. Conclusions: A risk-adapted, approach is recommended: omit LND for clinical T1a thymomas; perform N1 sampling for B2/B3 or T1b-T2 disease; perform systematic N1 + N2 dissection targeted by nodal stations for thymic carcinoma and thymic NET, including the right paratracheal station regardless of laterality. Persistent gaps include the absence of prospective randomized data, heterogeneous definitions of LND, and lack of validated preoperative radiologic predictors. A multinational prospective registry-based trial is warranted.