Effects of primary tumor location in the basal segment or superior segment (S6) on patient survival in lung cancer: a meta-analysis.

Background: Among the key factors influencing the prognosis of lung cancer, the primary tumor site has garnered significant attention in recent years, as it may affect the surgical difficulty and the risk of lymph node metastasis, thereby impacting overall prognosis. Numerous retrospective studies have produced conflicting conclusions, highlighting the necessity for a meta-analysis to consolidate these findings and ascertain the effects of primary tumor location in the basal versus superior segment of the lower lobe(S6) on survival outcomes.

Methods: We conducted a comprehensive literature search up to January 2025 and identified six relevant retrospective studies. We then used the random-effects model in Stata software to perform a meta-analysis to evaluate the impact of the primary tumor location on overall survival(OS) and event-free survival(EFS), EFS was defined as an aggregate of freedom from recurrence (FFR), disease-free survival (DFS), and progression-free survival (RFS).

Result: This study demonstrated that there were no statistically significant differences in OS (S6 vs. Basal segment HR = 1.40, 95% CI: 0.81,2.42 I²=71.8%) and EFS(S6 vs. Basal segment HR = 1.32, 95% CI: 0.69,2.54, I²=76.6%) between patients with the tumor in the S6 segment or basal segment. Begg's test did not find publication bias (p > 0.05). Subgroup analysis indicated that the year of publication, clinical stage, sample size, and both univariate and multivariate analyses did not significantly influence the results.

Conclusion: The direct impact of tumor location (S6 vs. Basal segment)on survival is not statistically significant.