Optimal radial force and size for palliation in gastroesophageal adenocarcinoma: a comparative analysis of current stent technology

A functional stent with near-infrared light triggered localized photothermal-chemo synergistic therapy for malignant stenosis of esophageal cancer

Stent implantation is a widely used palliative treatment for relieving strictures in malignant esophageal cancer. However, conventional fully covered stents play a role in preventing the tumor from ingrowth but increasing the risk of migration. Therefore, there is an urgent need for a multifunctional stent that not only reduces migration but also provides synergistic therapeutic benefits to inhibit tumor growth. This study proposed a braided esophageal stent with synergistic photothermal and chemotherapy functions to achieve precise controllable drug release. The stent was braided of Nitinol fiber and polyethylene terephthalate fiber in one-step, in which Nitinol loaded with high-efficiency photothermal conversion agent gold nanoparticles and polyethylene terephthalate loaded anti-tumor drugs release mediated by a temperature-responsive coating. The stent showed anti-migration ability and orchestrated the localized hyperthermia plus thermal-stimuli drug release during the tumor lesion. Cell experiments confirmed that the stent showed a significantly synergistic tumor cell killing effect (28.29 %). In 3D tumor sphere model, the apoptosis rate of tumor cells reached 31.34 %. In summary, the composite stent design strategy integrates anti-migration features and photoheating-controlled drug release for synergistic cancer therapy, providing a new design idea for the application of nickel-titanium alloy stents in the treatment of malignant esophageal stenosis.

Safety and Efficacy of Self-Expandable Metallic Stent Placement Using Low Radial Force Stent for Malignant Dysphagia after Radiotherapy

INTRODUCTION

We aimed to investigate the safety and efficacy of self-expandable metallic stent (SEMS) placement in patients with prior radiotherapy (RT) using the Niti-S stent, which is characterized by low radial force, in comparison to patients without prior RT.

METHODS

A consecutive series of 83 patients who were treated by SEMS placement using Niti-S stent for severe malignant esophageal obstruction or fistula were enrolled. The adverse event rates and efficacy were retrospectively compared between patients with/without prior RT before SEMS placement (RT group [n = 32] versus non-RT group [n = 51]).

RESULTS

The incidence rate of major adverse events in the RT group was 6.3% and was not significantly different from that in the non-RT group (5.9%, p = 0.95). Among the RT group, 84.4% were able to resume oral intake within a median of 2 days. Among the patients with fistula, 78.6% could resume oral intake and survive for 73 days after SEMS placement. Cox proportional hazard regression analysis identified significant factors affecting overall survival to be prior RT (hazard ratio [HR]: 1.96), low performance status (HR: 3.87), and subsequent anticancer treatment after SEMS placement (HR: 0.41). However, compared to the non-RT group, the RT group had received longer duration of anticancer treatment before SEMS placement and a lower rate of subsequent anticancer treatment after SEMS placement.

CONCLUSIONS

With the Niti-S stent, the incidence of major adverse events was sufficiently low even for patients after RT. SEMS with low radial force would be an effective palliative treatment option for patients, regardless of prior RT.

A Complex In Vitro Degradation Study on Polydioxanone Biliary Stents during a Clinically Relevant Period with the Focus on Raman Spectroscopy Validation

Biodegradable biliary stents are promising treatments for biliary benign stenoses. One of the materials considered for their production is polydioxanone (PPDX), which could exhibit a suitable degradation time for use in biodegradable stents. Proper material degradation characteristics, such as sufficient stiffness and disintegration resistance maintained for a clinically relevant period, are necessary to ensure stent safety and efficacy. The hydrolytic degradation of commercially available polydioxanone biliary stents (ELLA-CS, Hradec Králové, Czech Republic) in phosphate-buffered saline (PBS) was studied. During 9 weeks of degradation, structural, physical, and surface changes were monitored using Raman spectroscopy, differential scanning calorimetry, scanning electron microscopy, and tensile and torsion tests. It was found that the changes in mechanical properties are related to the increase in the ratio of amorphous to crystalline phase, the so-called amorphicity. Monitoring the amorphicity using Raman spectroscopy has proven to be an appropriate method to assess polydioxanone biliary stent degradation. At the 1732 cm⁻¹ Raman peak, the normalized shoulder area is less than 9 cm⁻¹ which indicates stent disintegration. The stent disintegration started after 9 weeks of degradation in PBS, which agrees with previous in vitro studies on polydioxanone materials as well as with in vivo studies on polydioxanone biliary stents.

Palliation of malignant dysphagia with a segmented self-expanding metal stent: A STROBE-compliant article

ABSTRACT

Self-expanding metal stents (SEMSs) in different geometric shapes are an established palliative treatment for malignant tumors of the esophagus. Mechanical properties and stent design have an impact on patient comfort, migration rate, and removability. SEMS with a segmented design (segSEMS) have recently become available on the market, promising new biomechanical properties for stent placement in benign and malignant esophageal diseases. In this study, we evaluated recurrent dysphagia, quality of life as well as technical success and complications for segmented SEMS-implantation in a retrospective study in palliative patients with dysphagia caused by malignant tumors of the esophagus.Between May 2017 and December 2018, patients presented to the interdisciplinary department of endoscopy of the University Hospital Cologne underwent segmented SEMS placement for malignant dysphagia. Patient follow-up was evaluated, and complications were monitored. Quality of life and functional improvement were monitored using the EORTC QLQ-C30 and QLQ-OE18.A total of 20 consecutive patients (16 men, 4 women; mean age: 65.5, range: 46-82) participated in the study and were treated with 20 segSEMS in total. The success rate of stent placement was 100%. Stent migration occurred in 3 patients (15.0%). Insertion of segSEMS immediately lead to a 48.0% reduction of dysphagia in the first 2 months (P < .001). Pain while eating (odynophagia) could also be significantly reduced by 39.6% over the first 2 months (P < .001).Implantation of segSEMS is a feasible and effective treatment for dysphagia in palliative patients with malignant tumors of the esophagus, offering immediate relief of symptoms and gain of physical functions.

The modern approach to esophageal palliative and emergency surgery

Thoracic surgeons currently have multiple options and strategies to guide treatment in esophageal palliative and emergency conditions. To guide the selection of an individualized palliative approach, physicians, including thoracic surgeons, must take into consideration many factors including prognosis, performance status and comorbidities of patients. For dysphagia more specifically, esophageal stent placement is the most widely used intervention for rapidly relieving dysphagia in inoperable esophageal cancer patients. The combination of esophageal stent placement with other therapies has an impact on palliative care. Innovations including radioactive stents, drug-eluding stents and biodegradable stents will require further evaluation and validation studies. Currently, patients with inoperable esophageal cancer have access to oncological and biological therapies that are improving their prognosis. A shift toward restaging and potential curative intent is occurring in current clinical practice. In acute intrathoracic esophageal perforation cases, high index of suspicion, multidisciplinary team expertise, antibiotics and hybrid treatment strategies, have significantly improved outcomes of patients in recent years. Hybrid treatment strategies denote the combination of minimally invasive interventions for source control and endoluminal procedures to seal the esophageal perforation. Endoluminal procedures as treatment of acute intrathoracic esophageal perforation include stent placement, over-the-scope clip and endoluminal vacuum therapy. Future perspective in the management of esophageal perforation seems to be the combination of endoluminal therapies tailored to the specific clinical scenario. Thoracic surgeons benefit from mastering endoluminal therapies and advanced endoscopic techniques. An understanding of these rapidly evolving therapies, i.e., outcomes, limitations and innovations, is required to optimally manage esophageal palliative and emergency conditions.

Outcomes of Esophageal Stent Therapy for the Management of Anastomotic Leaks

BACKGROUND

The purpose of this study was to present the optimal patient selection for esophageal stenting after esophageal resection to investigate possible factors leading to treatment success or treatment failure in these patients.

METHODS

This was a prospective, observational study of patients from January 2005 to May 2019 with an esophageal anastomotic leak that were treated with a self-expandable stent (SES).

RESULTS

A total of 34 patients were treated. All achieved technical success (100%); 33 (97%) achieved clinical success. No patient had to have reoperative surgery based on their leak management. The stenting in-hospital mortality was 0% with 1 patient (2%) with a 90-day mortality from possible leak-related death. Patients had their stents removed with a median of 106 days.

CONCLUSIONS

Stenting for an anastomotic leak after resection offers a safe and effective method of treatment and is successful in the majority of cases. Critical to success is optimal patient selection, adequate leak drainage, and optimal stent selection and placement.

Esophageal metal stent for malignant obstruction after prior radiotherapy

The association between severe adverse events (SAEs) and prior radiotherapy or stent type remains controversial. Patients with esophageal or esophagogastric junctional cancer who underwent stent placement (2005-2019) were enrolled in this retrospective study conducted at a tertiary cancer institute in Japan. The exclusion criteria were follow-up period of < 1 month and insufficient data on stent type or cancer characteristics. We used Mann-Whitney's U test for quantitative data and Fisher's exact test for categorical data. Multivariate analysis was performed using a logistic regression model. 107 stents were placed. Low radial-force stents (L group) were used in 51 procedures and high radial-force stents (H group) in 56 procedures. SAEs developed after nine procedures, the median interval from stent placement being 6 days (range, 1-141 days). SAEs occurred more frequently in the H (14%: 8/56) than in the L group (2%: 1/51) (P = 0.03). In patients who had undergone prior radiotherapy, SAEs were more frequent in the H (36%: 4/11) than in the L group (0%: 0/13) (P = 0.03). Re-obstruction and migration occurred after 16 and three procedures, respectively; these rates did not differ significantly between groups (P = 0.59, P = 1, respectively). Low radial-force stents may reduce the risk of SAEs after esophageal stenting.

Comparing the mechanical properties of a self-expandable metallic stent for colorectal obstruction: Proposed measurement method of axial force using a new measurement machine

OBJECTIVES

Colorectal stenting is widely performed using self-expandable metallic stents (SEMSs), but the mechanical properties have not been evaluated. Therefore, we conducted an in vitro study to evaluate the mechanical properties of colorectal SEMSs.

METHODS

Eighteen individual types and sizes of uncovered SEMSs were evaluated for their mechanical properties. Radial force was measured using a measurement machine. Axial force (AF) was measured by two methods: a conventional manual method and a new method using a measurement machine. The correlation of these two methods was evaluated. We also proposed an "AF zero border" that was defined as the angle at which the torque force disappeared.

RESULTS

Radial force versus diameter curves and AF versus angle curves were influenced by the structure and the size of each stent. There was excellent correlation of AFs measured by the new and conventional manual method (y = 21.434x, R = 0.881, P < 0.0001). Colorectal SEMSs could be categorized into five subgroups according to the mechanical properties. Most hook-wired SEMSs had the AF of zero border.

CONCLUSIONS

This is the first report to evaluate the mechanical properties of colorectal SEMSs, and these data may provide useful information for the clinical use and development of colorectal SEMS. Furthermore, the new measurement machine might standardize the measuring method of AF.

Comparison of 125 Iodine Seed-Loaded Stents with Different Diameters in Esophageal Cancer: A Multicenter Retrospective Cohort Study

Currently, there are no recommendations or guidelines concerning the preferred diameter of esophageal stents for palliative treatment, owing to the lack of adequate evidence. We therefore conducted a retrospective cohort study to evaluate whether 18 mm stents would achieve a similar function of dysphagia relief with fewer complications and longer survival compared to 20 mm stents. Esophageal cancer patients who underwent 125 iodine seed-loaded stent placement with a diameter of either 18 mm (n = 103) or 20 mm (n = 54) were included at five hospitals in China. The stabilized inverse probability of treatment weighting (IPTW) was used to control potential confounding factors and bias that are inherent in a retrospective study. The primary endpoint was dysphagia relief. Stent-related complications and overall survival were assessed as the secondary endpoints. In the IPTW-adjusted analysis, no significant difference was found in the dysphagia score between the two groups either at 1 week after stent placement or at the last week before death. Despite a comparable rate of overall complications, there was a significantly lower incidence of severe retrosternal pain (15.4% vs. 32.7%, p = 0.013) and a trend toward longer survival (median survival, 176 days [95% confidence interval (CI) 144 to 209] vs. 109 days [92 to 126], p = 0.057) in the 18 mm group. An irradiated stent with a diameter of 18 mm showed a similar outcome of dysphagia relief to that achieved with a 20 mm diameter stent, but halved the incidence of retrosternal pain after stent placement.

Tracheomalacia as Complication of Stenting for Esophageal Injury After Transsternal Approach to High Thoracic Vertebral Metastasis

BACKGROUND

Esophageal injury is a severe surgical complication of a transsternal approach to high thoracic vertebral metastasis, which can result in mediastinitis and life-threatening consequences. A covered stent can be placed in the esophagus to prevent mediastinal leakage. However, tracheomalacia is a rare complication following esophageal stenting.

CASE DESCRIPTION

A 56-year-old man had a pathologic fracture of the T3 vertebral body with spinal cord compression, myelopathy, and neurogenic bladder. An esophageal injury was noticed during the transsternal approach. Immediate suture repair, drainage tube placement, and subsequent esophageal stenting were carried out. One month after discharge, the endoscopic examination revealed nonhealing of the esophagus, and a new covered stent was replaced. Episodes of severe stridor and dyspnea led to the patient being sent to the emergency department. Computed tomography scan of the chest revealed a focal collapse of the trachea at the thoracic inlet, and tracheomalacia was suspected. The covered stent was removed, despite nonhealing of the esophagus. His stridor, dyspnea, and constant coughing subsided afterwards. The endoscopic examination at 3 months after stent removal showed complete healing of the esophagus.

CONCLUSIONS

Esophageal stenting can be used to prevent mediastinal leakage due to esophageal injury in the transsternal approach for high thoracic vertebral metastasis, but the stent might be a cause of tracheomalacia. Stent removal should be considered if upper airway obstruction occurs. Awareness of the radial force of the stent, esophageal composition (e.g., status post suture repair), and esophageal diameter must be considered for optimal stent tolerance to avoid complications.

Palliation of dysphagia

Palliation of dysphagia is the cornerstone of palliative treatment in patients with incurable oesophageal cancer. Available palliative options for dysphagia are oesophageal stent placement and radiotherapy. In general, oesophageal stent placement is the preferred therapeutic option in patients with a relatively poor prognosis because of its rapid relief of dysphagia. Regardless of ongoing technical developments, recurrence of dysphagia and stent-related complications are still occurring. For patients with a relatively good prognosis, intra-luminal brachytherapy is advised because of its sustained palliation of dysphagia. Due to limited availability of intra-luminal brachytherapy in clinical practice, fractionated external beam radiation therapy is commonly applied as an alternative. Selection of the optimal palliative approach for patients remains however challenging as conclusive high-quality evidence is limited. Moreover, with the introduction of new palliative treatment options (e.g. palliative chemotherapeutic and radiotherapeutic options) and the concurrent change of patient characteristics, supporting evidence from large randomised studies is warranted.

Esophageal Stenting in Clinical Practice: an Overview

OPINION STATEMENT

PURPOSE OF REVIEW: Esophageal stents are used in clinical practice for endoscopic treatment of a wide variety of esophageal diseases and conditions. This review provides key principles and a literature update on the utility and limitations of esophageal stenting in clinical practice.

RECENT FINDINGS

Indications for esophageal stenting can be subdivided into two groups. The first group consists of patients with malignant or benign dysphagia, in which an esophageal stent restores luminal patency. In the past years, temporary stent placement has increasingly been used in the therapeutic management of refractory benign esophageal strictures. When endoscopic repeated bougie dilation and other endoscopic treatment modalities have failed, an esophageal stent could be considered. Based on the literature, a fully covered self-expandable metal stent may be the preferred choice for the treatment of both malignant and benign dysphagia. The second group consists of patients with leakage from the esophageal lumen into the surrounding tissue. Esophageal leakage can be subdivided into three forms, benign esophageal perforations (iatrogenic and spontaneous), anastomotic leakage after reconstructive esophageal surgery, and fistula. In a carefully selected group of patients, a covered esophageal stent may be used for sealing off the leakage, thereby preventing further contamination of the tissue surrounding the defect. The past few years, several validated prediction tools have been developed that may assist clinicians in the selection of patients eligible for esophageal stent placement. Based on retrospective studies and expert opinion, a partially or fully covered self-expandable metal stent may have a role in treatment of esophageal leakage. Research do date supports the utilization of esophageal stents for the treatment of malignant or benign dysphagia and esophageal leakage.