Optimal Lymph Node Examination and Adjuvant Chemotherapy for Stage I Lung Cancer

Area of Science:

• Oncology
• Thoracic Surgery
• Cancer Staging

Background:

• Accurate staging is critical for effective treatment of stage I lung cancer.
• The optimal number of lymph nodes (LNs) to examine for accurate staging and prognostic stratification remains debated.

Purpose of the Study:

• To determine the optimal number of lymph nodes (LNs) examined in stage I lung cancer.
• To evaluate the role of adjuvant chemotherapy in patients with suboptimal nodal staging.

Main Methods:

• Analysis of the National Cancer Database (2006-2014) for surgically treated stage I lung cancer patients (N=65,438).
• Multivariate Cox models determined optimal LN counts, validated in a clinical stage I cohort (N=117,112).
• Adjuvant chemotherapy efficacy assessed in T1-T2a stages with suboptimal LN examination.

Main Results:

• Examining 8, 9, 10, and 11 LNs for T1a, T1b, T1c, and T2a tumors, respectively, correlated with improved survival.
• The 8-11 LN threshold independently predicted nodal upstaging (OR=1.706) and survival (HR=0.890).
• Adjuvant chemotherapy improved survival in T2a patients with suboptimal staging (HR=0.841) but not in T1a-T1c stages.

Conclusions:

• Lymph node evaluation is crucial for accurate staging and treatment in lung cancer.
• Examining 8-11 LNs is vital for predicting upstaging and survival outcomes in stage I lung cancer.
• Adjuvant chemotherapy may benefit T2a patients with suboptimal nodal staging.