Predictors and Patterns of Hilar Lymph Node Metastasis by Tumour Location in Clinical Stage IA Pure-solid Non-small-cell Lung Cancer

OBJECTIVES: Segmentectomy for radiologically pure-solid non-small-cell lung cancer remains controversial due to the high rate of occult lymph node metastasis. Certain hilar lymph nodes (HLN) can be challenging to resect during segmentectomy, especially non-adjacent interlobar lymph node (non-aiLN) distant from the primary tumour. We aimed to elucidate whether HLN metastasis can be predicted more accurately in clinical stage IA pure-solid tumours. METHODS: Between 2009 and 2023, 693 consecutive patients with clinical stage IA pure-solid tumours who underwent lobectomy with HLN dissection were included. The frequencies of HLN and non-aiLN metastases were evaluated. Predictors of HLN metastasis were assessed using multivariable logistic regression analysis. RESULTS: HLN and non-aiLN metastases were detected in 110 (15.9%) and 34 patients (4.9%), respectively. Multivariable logistic regression analysis revealed that carcinoembryonic antigen (CEA) level (P < .01), left side (P = .04), maximum standardized uptake value (SUVmax) (P < .01), and adenocarcinoma (P < .01) were independent predictors of HLN metastasis. Furthermore, in tumours with high SUVmax >5.0 and CEA >5.0 ng/mL, based on the results of the multivariable logistic regression model, the frequency of HLN metastasis increased to 23.0% (28/122). Additionally, 9 (32.1%) tumours had non-aiLN metastases. CONCLUSIONS: HLN and non-aiLN metastases were frequent among clinical stage IA pure-solid tumours, especially in those with SUVmax >5.0 and CEA >5.0 ng/mL. HLN dissection during segmentectomy should be performed carefully in patients with clinical stage IA pure-solid tumours with high SUVmax and CEA.