Hilar Lymphadenectomy Is Associated With Improved Disease-Free Survival in Pathologically N0 Non-Small Cell Lung Cancer.

BACKGROUND

Aim of this study is to evaluate the prognostic role of nodal parameter in early stage pathologically patients with N0 who underwent lobectomy and lymphadenectomy.

METHODS

Clinical and pathological characteristics of patients who underwent anatomical lung resection from 1/01/2010 to 31/12/2019 were reviewed and retrospectively analyzed. GGO and part-solid tumors, MIA, AIS, more than 5 cm in size, with nodal and/or distant metastases, or receiving neoadjuvant treatment were excluded. Operatory and pathological report were reviewed to collect data on lymphadenectomy. The primary end-point was disease-free survival (DFS), calculated from surgery to recurrence appearance. Clinical/pathological characteristics and nodal parameters were associate to DFS using Kaplan-Meier curves. The log-rank test was used to assess differences between subgroups. A multivariable model was built using Cox-regression analysis, including variable resulting significant (p value < 0.05), at univariable analysis.

RESULTS

The final analysis was conducted on 487 patients. Most patients presented stage I tumor (82.4%). The mean number of resected nodes (#RN), resected N1 (#RN1) nodes, and resected N2 nodes (#RN2) resulted 9.5 ± 8.0, 3.4 ± 4.3, and 5.9 ± 4.4. The mean number of total resected stations (#RS), N1 resected stations (#RSN1), and N2 resected stations (#RSN2) resulted 2.5 ± 1.6, 1 ± 0.8, and 1.5 ± 1.2, respectively. During a mean follow-up of 43 ± 28 months, a recurrence occurred in 137 (28.1%) patients. At univariable analysis, age < 70 years (p = 0.025), N1 lymphadenectomy (p = 0.019), #RSN1 ≥ 3 (p = 0.001), #RN ≥ 10 (p = 0.019), #RN1 ≥ 3 (p < 0.001), node sampling with more than 3 resected nodes (p = 0.049), at least 3 stations with 3 N1 nodes resected (p = 0.013), at least 3 stations resected with 10 lymphnodes, and 3N1 lymphnodes (p = 0.020) significantly correlated with improved DFS. Multivariable analysis confirmed as independent prognostic factor #RN1 ≥ 3 (p = 0.017; HR 1.782; and 95% CI: 1.107-2.867). Patients with #RN1 ≥ 3 presented a 5-years DFS of 76.3% versus 57.8% of patients with #RN1 < 3 (p = 0.001).

CONCLUSIONS

Hilar lymphadenectomy seems to significantly correlate with disease-free survival in patients with pN0NSCLC and should be better defined in lymphadenectomy guidelines.