Diabetes mellitus and survival of non-small cell lung cancer patients after surgery: A comprehensive systematic review and meta-analysis.

Background: Diabetes mellitus (DM) is one of the most common comorbidities in surgically treated non-small cell lung cancer (NSCLC) patients and has a negative impact on short-term outcomes. However, the impact of DM on long-term survival of such patients remains controversial; therefore, we conducted a comprehensive updated meta-analysis.

Methods: We systematically searched relevant studies in PubMed, Embase, Cochrane Library, and Web of Science up to 6 September 2018. Hazard ratios (HRs) for the impact of DM on overall survival (OS) and recurrence-free survival (RFS) of patients with surgically treated NSCLC were extracted and analyzed using the STATA 12.0 package.

Results: We included 13 cohort studies consisting of 4343 patients (730 patients with DM and 3613 patients without) with surgically treated NSCLC. Meta-analysis showed that patients with DM had significantly poorer OS (random effects: HR 1.30, 95% confidence interval 1.05-1.60; P = 0.016) than those without. However, with a limited sample size, there was no significant difference in RFS (random effects: HR 1.06, 95% confidence interval 0.71-1.58; P = 0.786) between patients with and without DM after surgical resection of NSCLC.

Conclusion: DM is an independent unfavorable prognostic factor for patients with surgically treated NSCLC. High-quality studies with appropriate adjustment for confounding factors are needed to confirm our conclusions.