Patients diagnosed with MGOO that presented with unresectable disease or were in palliative treatment, and that underwent SEMS placement, were included in the study.

The inclusion criteria were patients above 18 years of age, with endoscopically demonstrated obstruction of the distal stomach or duodenum that made oral intake difficult, patients that had a gastric outlet obstruction scoring system (GOOSS) score ≤ 2 (Table 1), biopsies conclusive of malignant neoplasia, and computed axial tomography studies from which the presence of ascites, carcinomatosis, distant metastasis, and unresectable disease was evaluated. The exclusion criteria were pregnant patients, gastrointestinal perforation, peritonitis, obstruction distal to the MGOO, SEMS placement not performed at the Instituto Nacional de Cancerología, no electronic case record, and follow-up that was under 7 days.

An Olympus GIF-1T140 and GIF-1TQ160 therapeutic gastroscope was utilized for SEMS placement. The location and length of the obstruction was evaluated by endoscopy and fluoroscopy with contrast medium. A biliary hydrophilic guidewire was then introduced through the stricture and the SEMS was introduced over the guidewire and released under endoscopic and fluoroscopic guidance. The selection of the length of the SEMS was based on the length of the stricture. An additional 4 cm was considered to ensure 2 cm of stent before and after the ends of the stricture. SEMS selection was based on the experience of the endoscopist. Four endoscopists with more than 10 years of experience in SEMS placement participated in the study. The 3 types of SEMS utilized were the WallFlex Duodenal Stent (Boston Scientific) and the WALLSTENT Duodenal Stent (Boston Scientific), both uncovered stents (ucSEMSs), and the Niti-S Pyloric/Duodenal Stent (Taewoong Medical), a partially covered SEMS (pcSEMS).

We used the GOOSS, which assigns points depending on the patient’s level of oral intake, enabling oral intake capacity to be objectively evaluated (Table 1). The GOOSS was created in 2002 as a scoring system to assess oral intake in patients with malignant dysphagia30 and is currently the scale used in numerous studies on MGOO.26,27,29

Clinical success was defined as a GOOSS score ≥ 2 after 7 days of SEMS placement. Technical success was defined as the precise positioning of the SEMS at the obstruction site. SEMS dysfunction was defined as the reappearance of symptoms of GOO with a GOOSS score < 2 and radiologic or endoscopic evidence of tumor ingrowth or SEMS collapse, breakage, migration, or food impaction. The duration of SEMS permeability was defined as the time from SEMS placement to its dysfunction. When there was no dysfunction, SEMS permeability duration was considered the same as the length of time of the patient’s subsequent survival.

The following variables for predicting SEMS dysfunction were analyzed: age, sex, primary cancer organ, histologic type, obstruction location (antrum, pylorus, duodenum), stricture length, obstruction type (intrinsic or extrinsic), KS, clinical stage, ascites, carcinomatosis, SEMS type (commercial brand, pcSEMS, ucSEMS), and adjuvant treatment (chemotherapy and radiotherapy after SEMS placement).

Intrinsic stricture was considered when the endoscopically viewed tissue had a tumor-like aspect that conditioned a reduction in the gastric or duodenal lumen, and extrinsic stricture was considered when there was a reduction in the gastric or duodenal lumen with normal mucosa.

To evaluate the nutritional impact of SEMS in MGOO, body mass index (BMI) and serum albumin levels were assessed before and after SEMS placement.

Follow-up was carried out through the electronic records up to May 2018, death of the patient, or loss to follow-up.

Utilizing the SPSS version 23 program, a descriptive analysis was performed with measures of dispersion for the quantitative variables and proportions for the qualitative variables. A univariate model was used for the inferential analysis, employing the Student’s t test for the quantitative variables and the chi-square test for the qualitative variables. Statistical significance was set at a p < 0.05, with a 95% confidence interval (95% CI).

The authors declare that no experiments were conducted on humans or animals in the present study. Written statements of informed consent were obtained from all the patients, with absolute maintenance of their anonymity. The present study was approved by the ethics committee of the Instituto Nacional de Cancerología in Mexico City.

Table 2 shows the demographic and clinical characteristics of the study patients. A total of 51.2% (n = 22) of the patients were women and 48.8% (n = 21) were men, and the mean patient age was 56.12 ± 14.38 years. The stomach was the primary cancer organ in 76.7% (n = 33) of the patients and primary involvement was pancreatobiliary in 23.2% (n = 10) (pancreas in 7, ampulla of Vater in 2, common bile duct in 1). The histologic type of cancer was diffuse gastric adenocarcinoma in 41.9% (n = 18), intestinal gastric adenocarcinoma in 27.9% (n = 12), pancreatobiliary adenocarcinoma in 23.3% (n = 10), and large cell Hodgkin’s lymphoma in 7.0% (n = 3). The KS was 67.67 ± 18.23. A total of 16.3% of the patients (n = 7) had clinical stage III disease, 2.3% (n = 1) had stage IIIB, and 81.4% (n = 35) had stage IV. A total of 60.5% (n = 26) of the patients presented with ascites and 39.5% (n = 17) had carcinomatosis. The most frequent obstruction location was the pylorus, found in 58.1% (n = 25) of the patients, followed by the duodenum in 30.2% (n = 13) and the antrum in 11.6% (n = 5). There was intrinsic obstruction in 83.7% of the patients (n = 36), intrinsic and extrinsic obstruction in 13.9% (n = 6), and extrinsic obstruction in 2.3% (n = 1). The length of the obstruction was 28.84 ± 13.31 mm. The SEMS utilized were: WallFlex 72.1%, WALLSTENT 14.0%, and Niti-S 13.9%, of which 95.3% were ucSEMSs and 4.7% were pcSEMS. A total of 72.1% of the patients (n = 31) received adjuvant chemotherapy and 7.0% (n = 3) underwent adjuvant radiotherapy. Seven patients presented with bile duct obstruction. Six of them required endoscopic bile duct drainage (through endoscopic retrograde cholangiopancreatography or endoscopic ultrasound) and one patient had percutaneous bile duct drainage.

The technical success of SEMS placement was 97.7% (n = 42) and the clinical success was 88.3% (n = 38). Initial SEMS placement was technically unsuccessful in one patient with obstruction in the antrum because the SEMS was released in the duodenum, but a second SEMS was successfully placed at the obstruction site during the same endoscopy. A total of 95.3% (n = 41) of the patients had a GOOSS score of 0 or 1 prior to SEMS placement and 86% (n = 37) had a GOOSS score of 2 or 3 after SEMS placement (Table 3).

SEMS dysfunction occurred in 30.2% (n = 13) of the patients, with the following characteristics: 38.5% (n = 5) were men and 61.5% (n = 8) were women; the stomach was the primary cancer organ in the majority of patients (92.3%) (n = 12); the most frequent histologic type was diffuse gastric adenocarcinoma (46.2%) (n = 6), followed by intestinal gastric adenocarcinoma (23.1%) (n = 3); the majority of the patients had clinical stage IV disease (92.3%) (n = 12), 76.9% (n = 10) presented with ascites, and 38.5% (n = 5) had carcinomatosis. The most frequent obstruction site was the pylorus (76.9%) (n = 10), followed by the duodenum (15.4%) (n = 2); 92% of the patients had intrinsic obstruction (n = 12) and 7.6% had intrinsic and extrinsic obstruction (n = 1); the WallFlex stent was the SEMS used in 69.2% (n = 9) of the patients and ucSEMSs were used in 84.6% (n = 11). The majority of patients received adjuvant chemotherapy (84.6%) (n = 11) and only 7.7% (n = 1) received adjuvant radiotherapy.

Tumor ingrowth was the cause of SEMS dysfunction (Table 4) in 92.3% (n = 12) of the patients, food impaction in 7.6% (n = 1), and lack of angled expansion in 7.6% (n = 1). One patient had two causes of SEMS dysfunction (tumor ingrowth and food impaction). SEMS dysfunction was resolved in 53.8% of the patients (n = 7). The resolution method was the placement of another SEMS in 3 patients, argon plasma electrocoagulation in 2 patients, and balloon dilation in 2 patients. In the unresolved SEMS dysfunction group, endoscopic resolution was not attempted in 2 patients and argon plasma coagulation failed in 3 patients, after which a nasojejunal tube was placed.

In the univariate analysis (Table 5), the histologic subtype of diffuse gastric adenocarcinoma (p = 0.02) and ucSEMSs (p = 0.02) were the variables associated with SEMS dysfunction that reached statistical significance. In addition, the stomach as the primary cancer organ (p = 0.06) and intrinsic obstruction (p = 0.57) showed a tendency to be significant predictors for SEMS dysfunction.

The SEMS permeability duration in the patients with SEMS dysfunction was 5.4 ± 3.5 months and dysfunction occurred in 7 patients in < 6 months after placement.

BMI was 20.6 ± 3.2 kg/m2 prior to SEMS placement and 20.7 ± 3.3 kg/m2 after SEMS placement. The serum albumin level was 3.23 ± 0.62 g/dl before SEMS placement and 3.05 ± 0.64 g/dl after SEMS placement. A sub-analysis was carried out on the 28 patients whose survival was greater than 1 month after SEMS placement. BMI in those patients was 19.7 ± 2.8 kg/m2 before SEMS placement and 20.2 ± 3.2 kg/m2 after SEMS placement and albumin level was 3.27 ± 0.60 g/dl before SEMS placement and 3.09 ± 0.59 g/dl after SEMS placement.

The mean follow-up period was 5.8 months (1-24 months).