Association between time to stent dysfunction and the anti-tumour effect of systemic chemotherapy following stent placement in patients with pancreaticobiliary cancers and malignant gastric outlet obstruction: a retrospective cohort study

Background Malignant gastric outlet obstruction (MGOO) occasionally occurs due to pancreaticobiliary cancer. Endoscopic duodenal stenting (DS) is a common treatment for MGOO. However, it has been reported that DS does not have sufficient patency time for it to be used in patients who have a potentially increased lifespan. Nowadays, systemic chemotherapy for pancreaticobiliary cancer has developed, and its anti-tumour effect would make time to stent dysfunction longer. Therefore, we retrospectively evaluated the association between objective response to systemic chemotherapy, followed by DS and time to stent dysfunction in patients with advanced pancreaticobiliary cancer. Methods This retrospective study included 109 patients with advanced pancreaticobiliary cancer who received systemic chemotherapy after DS. Patients who showed complete or partial response were defined as responders. The rest were defined as non-responders. Time to stent dysfunction was compared between responders and non-responders using the landmark analysis at 2 months after DS. Death without recurrence of MGOO was considered as a competing risk for time to stent dysfunction. Results Combination and monotherapy regimens were adopted for 46 and 63 patients, respectively. Median progression-free survival and overall survival were 3.2 months (95% confidence interval [CI], 2.4–4.0) and 6.0 months (95% CI, 4.6–7.3). Objective response was observed in 21 patients (19.3%). Median time to stent dysfunction was 12.5 months (95% CI, 8.4–16.5) in the entire cohort. In 89 patients, responders had a lower cumulative incidence of stent dysfunction than non-responders: 9.5 and 19.1% at 6 months, and 19.0 and 27.9% at 1-year, respectively. There was difference of time to stent dysfunction between responders and non-responders among patients who received combination regimen as the first-line treatment with p-value of 0.009: cumulative incidence was 0 and 42.9% at 6 months, and 9.3 and 57.1% at 1-year, respectively. Conclusions Longer time to stent dysfunction is expected when systemic chemotherapy following DS suppresses tumour progression; DS is slated to be a standard treatment for MGOO even in patients with pancreaticobiliary cancer and a long lifespan.