Stent placement for treatment of malignant superior vena cava syndrome: analysis on factors affecting stent patency rate

To evaluate the efficacy and safety of uncovered stent placement in patients with malignant superior vena cava syndrome and analyze factors associated with stent patency. Between January 2013 and June 2015, uncovered stent placement for malignant SVC syndrome was performed in 74 consecutive patients. Those who did not have follow-up CT scan within 30 days after stent placement were excluded (n=11). The cause of malignant SVC syndrome included small cell carcinoma, adenocarcinoma, squamous cell carcinoma, and etc. Stent patency and patient survival rates were calculated by using the Kaplan-Meier method. Stent placement was technically successful in all 63 patients. There were no procedure-related major complications. Of the 55 patients symptomatic prior to stent placement, 52 patients experienced improvement in their symptoms. The mean stent expansion rate was measured as 54% on immediate follow-up CT scan. As for stent dysfunction, there were two types of stent occlusion in 9 of 63 patients (14.3%): tumor overgrowth with/without (n=6) and in-stent thrombosis (n=3). Multivariate Cox regression analysis demonstrated that the stent expansion rate greater than 50% of its diameter and adjunctive radiation therapy were the significant factors associated with a better stent patency rate. Kaplan-Meier analysis revealed median patient survival of 186 days (95% CI, 135-237 days). Cumulative stent patency rates were 95%, 90%, 82%and 79%at 1,3,6, and 12 months, respectively. Placement of uncovered stent seems to be a safe and effective treatment option for malignant SVC syndrome. Common causes of stent dysfunction are tumor overgrowth with/without ingrowth and in-stent thrombosis. As the stent expansion rate was insufficient in most cases and it may lead to thrombotic occlusion of the stent, anticoagulation or antiplatelet medication can be considered, In addition, radiation therapy after SVC stenting can also be considered in that radiation therapy after SVC stenting is shown to help the stent expand more by decreasing tumor overgrowth with/without ingrowth.