The relative efficacy of covered self-expandable metal stents (CSEMS) and uncovered self-expandable metal stents (UCSEMS) for the palliation of malignant gastric outlet obstruction (mGOO) was assessed. Overall survival was poor with both methods, although complications were fewer with uncovered stents, according to the findings published in Gut. Stent efficacy also differed across patient subgroups defined by extrinsic malignancies.
This multicenter prospective study enrolled patients with mGOO from more than 40 tertiary care centers in Japan. Patients were randomly assigned 1:1 for deployment of CSEMS or UCSEMS and followed up for adverse events and clinical outcomes. Randomization was stratified by cause of mGOO and oral site of stenosis. The primary outcome was time to stent dysfunction in each study arm. Stent dysfunction was defined as appetite loss, nausea, and/or vomiting with a GOO scoring system (GOOSS) score <2 and confirmation of obstruction on imaging. Secondary outcomes included time to stent dysfunction; dysfunction-free survival at 1, 2, and 3 months; and survival probability over follow-up. Subgroup analyses were performed by tumor type (intrinsic vs extrinsic) and stenotic site (duodenum vs stomach).
A total of 366 patients underwent randomization between 2014 and 2017, among whom 182 received CSEMS and 184 received UCSEMS. The most common primary diseases were pancreatic cancer (48.9% in both the CSEMS and UCSEMS groups), gastric cancer (31.3% and 33.2%), and gallbladder cancer (5.5% and 6.5%). The probability of survival at 1, 2, and 3 months was 85.1%, 66.5%, and 49.7% in the CSEMS group and 85.8%, 64.5%, and 48.4% in the UCSEMS group, respectively. Overall survival was not significantly different between groups. However, the CSEMS group had a significantly higher prevalence of overall stent dysfunction (35.2% vs 23.4%; P=.01) compared with the UCSEMS group. This difference was mainly relevant among patients with extrinsic tumors, for whom the dysfunction rates for CSEMS and UCSEMS were 35.6% and 17.5%, respectively (P <.01). Time to stent dysfunction was also significantly shorter with CSEMS compared with UCSEMS in patients with extrinsic tumors. Among patients with intrinsic tumors, overall dysfunction rates were not different between stent types. However, stent ingrowth was more common with UCSEMS compared with CSEMS in this subgroup (27.7% vs 1.6%; P <.01). Outcomes for UCSEMS and CSEMS did not appear to differ based on stenosis site.
This is the largest study to date examining the relative efficacy of UCSEMS vs CSEMS. Contrary to the investigators’ initial hypotheses, the incidence of stent dysfunction was significantly higher in the CSEMS group compared with the UCSEMS group. This difference was largely driven by differential outcomes among patients with extrinsic tumors. Patients with intrinsic tumors did not have different outcomes based on stent type. However, poor survival in the overall cohort limits the relevancy of these data. In the context of the 2- and 3-month period following surgery, patients with extrinsic tumors may experience better benefit from UCSEMs compared with CSEMS.
“UCSEMS may be used among patients with malignant gastric outlet obstruction, particularly those with extrinsic [tumors], because a lower proportion of stent dysfunction is expected,” the investigators wrote.
Yamao K, Kitano M, Chiba Y, et al. Endoscopic placement of covered versus uncovered self-expandable metal stents for palliation of malignant gastric outlet obstruction. Gut. Published online November 22, 2020. doi:10.1136/gutjnl-2020-320775