Patterns of lymph node metastasis in patients with thymic neuroendocrine neoplasms

Lymph node metastasis (LNM) is frequent in patients with thymic neuroendocrine neoplasms (T-NENs), but detailed studies on metastatic patterns remain limited. This study integrates surgical, imaging, and pathologic data to characterize nodal spread, providing reference data to optimize lymph node dissection (LND) and radiotherapy planning.

Patients with pathologically confirmed T-NENs at our institution were included. Medical records were reviewed to obtain patient characteristics, treatment modalities, failure patterns, and survival outcomes. These data were subsequently analyzed.

Between September 2008 and December 2022, 72 patients (55 males, 17 females; median age 55 years, range 25-70 years) were included. Pathologic subtypes comprised typical carcinoid (TC, n = 9), atypical carcinoid (AC) (n = 50), and neuroendocrine carcinomas (NEC) (n = 13). During a median follow-up of 53 months, cumulative lifetime nodal involvement (including baseline and recurrence) was observed in 67 patients (93.06%). Cumulatively, the most frequently involved stations were right lower paratracheal (51.39%), left perijugular (47.22%), and subcarinal (43.06%), with additional, less frequent involvement at other stations. The cumulative LNM rate was 100% in TC, 92.00% (46/50) in AC, and 92.31% (12/13) in NEC. The median progression-free survival was 23 months, and the 5-year overall survival was 63.31%.

This study summarizes detailed patterns of LNM and highlights the importance of locoregional treatment. The findings provide a reference for defining the extent of surgical dissection and designing radiotherapy clinical target volumes (CTV), and a basis for future prospective studies.