Impact of interstitial lung disease gender-age-physiology index in surgically treated lung cancer.

BACKGROUND

The postoperative prognosis of patients with interstitial lung disease (ILD) and lung cancer is poor. Recently, the ILD-gender-age-physiology (GAP) index was identified as a clinical prognostic factor for patients with ILD. This study investigated the ILD-GAP index and oncological factors regarding postoperative outcomes.

METHODS

We retrospectively reviewed 87 lung cancer patients with comorbid ILD who underwent curative resection at our institution between April 2005 and December 2019. Short-term postoperative outcomes and overall survival (OS) based on the ILD-GAP index were examined. OS rates after surgery were calculated using the Kaplan-Meier method, and group differences were analyzed using the Log-Rank test. Univariate and multivariate analyses for OS were performed using the Cox regression model.

RESULTS

Multivariate analyses revealed ILD-GAP index ≥ 4 [Hazard ratio, 3.349; 95% confidence interval 1.375-8.155; P = 0.008] as a factor associated with OS. In the ILD-GAP index ≥ 4 group, no deaths occurred from primary lung cancer, with respiratory-related deaths being the most common, and exacerbation of ILD was more frequent (P = 0.007). Regarding perioperative results, a significant difference was observed in 90-day mortality (2.7% vs. 23.0% [P = 0.022]), and more patients required home oxygen therapy (14.9% vs. 69.2% [P < 0.001]) in the ILD-GAP index ≥ 4 group.

CONCLUSIONS

An ILD-GAP index ≥ 4 indicated a poor prognostic factor for patients with surgically treated lung cancer. Careful consideration of surgical indications is essential for patients with an ILD-GAP index ≥ 4.