Prognostic impact of clinical outcome after endoscopic gastroduodenal stent placement for malignant gastric outlet obstruction: a multicenter retrospective cohort study using a time-dependent analysis

BACKGROUND: Endoscopic gastroduodenal stent (GDS) placement is widely used as a safe and effective method to rapidly improve gastrointestinal symptoms of malignant gastric outlet obstruction (MGOO). While previous studies reported the utility of chemotherapy after GDS placement for prognosis improvement, they did not fully address the issue of immortal time bias. OBJECTIVES: To examine the association between prognosis and clinical course following endoscopic GDS placement, using a time-dependent analysis. DESIGN: Multicenter retrospective cohort study. METHODS: This study included 216 MGOO patients who underwent GDS placement between April 2010 and August 2020. Data of patient baseline characteristics, including age, gender, cancer type, performance status (PS), GDS type and length, GDS placement location, gastric outlet obstruction scoring system (GOOSS) score, and history of chemotherapy before GDS were collected. The clinical course following GDS placement was evaluated by GOOSS score, stent dysfunction, cholangitis, and chemotherapy. A Cox proportional hazards model was used to identify prognostic factors after GDS placement. Stent dysfunction, post-stent cholangitis, and post-stent chemotherapy were analyzed as time-dependent covariates. RESULTS: Mean GOOSS scores before and after GDS were 0.7 and 2.4, respectively, with significant improvement after GDS placement (p < 0.001). The median survival time after GDS placement was 79 [95% confidence interval (CI): 68–103] days. In multivariate Cox proportional hazards model with time-dependent covariates, PS 0–1 [hazard ratio (HR): 0.55, 95% CI: 0.40–0.75; p < 0.001], ascites (HR: 1.45, 95% CI: 1.04–2.01; p = 0.028), metastasis (HR: 1.84, 95% CI: 1.31–2.58; p < 0.001), post-stent cholangitis (HR: 2.38, 95% CI: 1.37–4.15; p = 0.002), and post-stent chemotherapy (HR: 0.01, 95% CI: 0.002–0.10; p < 0.001) significantly affected prognosis after GDS placement. CONCLUSION: Post-stent cholangitis and tolerability to receive chemotherapy after GDS placement influenced prognosis in MGOO patients.