Impact of postoperative pulmonary complications on survival after gastrectomy for cancer: individual patient data meta-analysis

Background Pulmonary complications (PC) may occur in up to 6.8% of patients after gastrectomy. Although PC are associated with prolonged hospital stay and increased overall healthcare costs, their impact on long-term survival remains controversial. This study aimed to analyze the effect of PC on overall (OS) and cancer-specific survival (CSS) in patients undergoing gastrectomy for cancer. Methods Reconstructed individual patient data (IPD) meta-analysis was performed using restricted mean survival time difference (RMSTD) estimation. PubMed, Scopus, MEDLINE, Web of Science, ClinicalTrials.gov, Cochrane Central Library, and Google Scholar, were searched. Primary outcomes were OS and CSS. RMSTD, risk ratio (RR), standardized mean difference (SMD), and 95% confidence intervals (CI) were used as pooled effect size measures. PROSPERO CRD420261373423. Results Overall, 7916 patients were included for analysis (four retrospective single-center studies). Postoperative PC occurred in 6.2% of patients. At 60 months follow-up, the RMSTD analysis shows that patients experiencing PC had a significantly lower OS (–14.3 months; 95% CI − 21.3, − 7.2; p < 0.0001) and CSS (-5.5 months; 95% CI − 8.7, − 2.3; p < 0.0001). The time-varying OS hazard ratio analysis showed a significantly increased mortality hazard in patients with PC within the first 24 months (HR 1.31, 95% CI 1.08–1.58). Conclusion Postoperative PC seem to have a clinically negative impact on long-term OS and CSS after gastrectomy, with the greatest hazard for mortality concentrated in the first 24-month after surgery. Strategies to reduce postoperative PC through optimized perioperative management should be pursued and may improve long-term survival.