Prognostic comparison between superior and basal segments in pure-solid non-small cell lung cancer

Studies suggest that non-small cell lung cancer of the superior segment (S6) affects different lymphatic pathways and results in worse prognosis than basal segment tumors. We aimed to compare survival after lobectomy between non-small cell lung cancer in the S6 and basal segments, focusing specifically on pure-solid tumors, which have higher lymph node metastasis rates and worse prognosis.

We retrospectively reviewed patients with pure-solid, clinical N0 M0, ≤ 5-cm, lower-lobe non-small cell lung cancer who underwent lobectomy with hilar and mediastinal lymphadenectomy between April 2009 and December 2021. Overall survival, recurrence-free survival and clinicopathological characteristics were evaluated.

We categorized 157 patients into S6 (n = 58) and basal segment (n = 99) groups. The 5-year overall survival (66.4% vs. 68.6%, respectively; p = 0.519; hazard ratio, 1.19; 95% confidence interval, 0.70-2.03), and recurrence-free survival (54.8% vs. 65.5%, respectively; p = 0.452; hazard ratio, 1.22; 95% confidence interval, 0.72-2.06) rates were comparable between the S6 and basal segment groups. Multivariable Cox regression analyses indicated that tumor location was not associated with overall or recurrence-free survival. The S6 group showed a higher tendency for visceral pleural invasion compared with the basal segment group. Superior mediastinal lymph node metastasis was pathologically confirmed exclusively in the S6 group (two cases).

No significant difference in survival was observed between S6 and basal segment pure-solid non-small cell lung cancer after lobectomy with hilar and mediastinal lymph node dissection.