Impact of primary tumor location on survival outcomes and recurrence patterns in patients with stage III non-small cell lung cancer: A retrospective observational study.

Background

Prognostic impact of primary tumor location in stage III non-small cell lung cancer (NSCLC) remains unclear in the era of concurrent chemoradiotherapy (CCRT) followed by consolidation durvalumab. Whether a lower lobe origin continues to influence survival and recurrence patterns under standardized multimodality therapy has not been fully elucidated.

Methods

This multicenter retrospective study included 136 patients with stage IIIA-IIIC NSCLC treated with definitive CCRT and durvalumab in 2018-2024. Baseline characteristics, recurrence patterns, and survival outcomes were compared between the lower and non-lower lobe groups. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier analyses and Cox proportional hazards models.

Results

Patients in the lower lobe group were older and showed differences in concurrent chemotherapy regimens, whereas most other factors were balanced. Lower lobe origin was associated with shorter OS (p = 0.014) and PFS (p = 0.011). On multivariable analysis, lower lobe location remained independently associated with poorer OS (HR, 2.21; 95% CI, 1.29-3.79; p = 0.004) and PFS (HR, 2.03; 95% CI, 1.24-3.33; p = 0.005) after adjustment for clinically relevant covariates. Exploratory analyses suggested more frequent pleural dissemination and liver metastasis in lower-lobe tumors despite similar primary tumor progression.

Conclusions

Lower lobe origin was independently associated with poorer survival in patients with stage III NSCLC treated with CCRT followed by consolidation durvalumab. These findings suggest that primary tumor location may provide additional prognostic information, although its implications for treatment or surveillance strategies require further investigation.