Self-expanding metal stents (SEMS) provide superior outcomes compared to plastic stents for pancreatic cancer patients undergoing neoadjuvant therapy

Background: Neoadjuvant therapy is increasingly utilized for pancreatic cancer patients to decrease tumor burden in anticipation of later surgical resection. However, infectious complications such as life threatening cholangitis may occur for those with biliary obstruction. We hypothesized that placement of metal rather than plastic stents in such patients results in lower rates of stent-related complications, leading to improved clinical outcomes. Methods: Retrospective cohort of pancreatic cancer patients treated by the University of Michigan Multidisciplinary Pancreatic Cancer Destination Program between January 2005 and June 2010. Only patients undergoing neoadjuvant therapy with one or more biliary stents placed for malignant obstruction were studied. Time to stent complication was compared between metal and plastic stents. The complication rate was estimated as the ratio of complications to total stent exposure time and 95% confidence intervals were calculated. Results: 52 patients met inclusion criteria. A total of 113 stents were placed in 52 patients (70 plastic, 43 metal). The complication rate was almost 7 times higher with plastic stents, 0.20 (95% CI, 0.14-0.30), than with metal stents, 0.03 (95% CI, 0.01-0.06). Moreover, the rate of hospitalization for stent-related complications was 3-fold higher in the plastic stent group than the metal stent group. The first quartile estimate of time to stent complication was almost 5 times longer for metal than for plastic stents (44 vs. 200 days) (P<0.0001). Conclusion: Compelling evidence indicates that self-expanding metal, not plastic stents should be used for malignant biliary obstruction in patients undergoing neoadjuvant therapy for pancreatic cancer.