Association between preoperative diaphragmatic dome height for overall survival in patients with lung cancer and obstructive ventilatory disorder

BACKGROUND: To investigate the relationship between preoperative diaphragmatic dome height (DDH), measured on chest radiographs, and postoperative overall survival (OS) and disease-specific survival (DSS) due to respiratory-related deaths in patients with lung cancer and obstructive ventilatory disorder (OVD). METHODS: This single-center retrospective study included 302 patients with lung cancer and OVD who underwent lobectomy between 2017 and 2024. DDH was measured on chest radiographs 1 month preoperatively, and the patients were divided into the low DDH (lower than the first quartile, 18.8 mm) and high DDH (≥ 18.8 mm) groups. The associations of DDH with OS and DSS were evaluated using Cox proportional hazards models and Fine-Gray competing risk analysis, respectively. Kaplan-Meier curves and log-rank tests were used for survival comparisons. RESULTS: Overall, 65 patients (21%) died postoperatively. Cox proportional hazards and Fine-Gray analyses indicated that DDH (hazard ratio: 2.10, 95% confidence interval [CI]: 1.22-3.61, p < 0.01; subdistribution hazard ratio: 2.50, 95% CI: 1.14-5.45, p < 0.05) was an independent prognostic factor for 3-year OS and DSS. Furthermore, survival curve analysis demonstrated that the low DDH group had significantly lower 3-year OS (70% vs 85%, p < 0.01) and 3-year DSS (80% vs 92%, p < 0.01) compared with the high DDH group. CONCLUSIONS: DDH is an independent prognostic factor for OS and DSS in patients with lung cancer and OVD, suggesting that it can serve as a novel physiological marker for long-term prognosis.