Biodegradable stent placement before neoadjuvant chemoradiotherapy as a bridge to surgery in patients with locally advanced esophageal cancer

Comprehensive review of materials, applications, and future innovations in biodegradable esophageal stents

Esophageal stricture (ES) results from benign and malignant conditions, such as uncontrolled gastroesophageal reflux disease (GERD) and esophageal neoplasms. Upper gastrointestinal endoscopy is the preferred diagnostic approach for ES and its underlying causes. Stent insertion using an endoscope is a prevalent method for alleviating or treating ES. Nevertheless, the widely used self-expandable metal stents (SEMS) and self-expandable plastic stents (SEPS) can result in complications such as migration and restenosis. Furthermore, they necessitate secondary extraction in cases of benign esophageal stricture (BES), rendering them unsatisfactory for clinical requirements. Over the past 3 decades, significant attention has been devoted to biodegradable materials, including synthetic polyester polymers and magnesium-based alloys, owing to their exceptional biocompatibility and biodegradability while addressing the challenges associated with recurring procedures after BES resolves. Novel esophageal stents have been developed and are undergoing experimental and clinical trials. Drug-eluting stents (DES) with drug-loading and drug-releasing capabilities are currently a research focal point, offering more efficient and precise ES treatments. Functional innovations have been investigated to optimize stent performance, including unidirectional drug-release and anti-migration features. Emerging manufacturing technologies such as three-dimensional (3D) printing and new biodegradable materials such as hydrogels have also contributed to the innovation of esophageal stents. The ultimate objective of the research and development of these materials is their clinical application in the treatment of ES and other benign conditions and the palliative treatment of malignant esophageal stricture (MES). This review aimed to offer a comprehensive overview of current biodegradable esophageal stent materials and their applications, highlight current research limitations and innovations, and offer insights into future development priorities and directions.

Advanced Endoscopy for Thoracic Surgeons

The thoracic surgeon, well versed in advanced endoscopy, has an array of therapeutic options for foregut pathologic conditions. Peroral endoscopic myotomy (POEM) offers a less-invasive means to treat achalasia, and the authors' preferred approach is described in this article. They also describe variations of POEM, such as G-POEM, Z-POEM, and D-POEM. In addition, endoscopic stenting, endoluminal vacuum therapy, endoscopic internal drainage, and endoscopic suturing/clipping are discussed and can be valuable tools for esophageal leaks and perforations. Endoscopic procedures are advancing rapidly, and thoracic surgeons must maintain at the forefront of these technologies.

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.

Raman Spectroscopy as a Novel Method for the Characterization of Polydioxanone Medical Stents Biodegradation

Polydioxanone (PPDX), as an FDA approved polymer in tissue engineering, is an important component of some promising medical devices, e.g., biodegradable stents. The hydrolytic degradation of polydioxanone stents plays a key role in the safety and efficacy of treatment. A new fast and convenient method to quantitatively evaluate the hydrolytic degradation of PPDX stent material was developed. PPDX esophageal stents were degraded in phosphate-buffered saline for 24 weeks. For the first time, the changes in Raman spectra during PPDX biodegradation have been investigated here. The level of PPDX hydrolytic degradation was determined from the Raman spectra by calculating the area under the 1732 cm^-1 peak shoulder. Raman spectroscopy, unlike Fourier transform infrared (FT-IR) spectroscopy, is also sensitive enough to monitor the decrease in the dye content in the stents during the degradation. Observation by a scanning electron microscope showed gradually growing cracks, eventually leading to the stent disintegration. The material crystallinity was increasing during the first 16 weeks, suggesting preferential degradation of the amorphous phase. Our results show a new easy and reliable way to evaluate the progression of PPDX hydrolytic degradation. The proposed approach can be useful for further studies on the behavior of PPDX materials, and for clinical practice.

Esophageal stenting for benign and malignant disease: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2021

MALIGNANT DISEASE

1: ESGE recommends placement of partially or fully covered self-expandable metal stents (SEMSs) for palliation of malignant dysphagia over laser therapy, photodynamic therapy, and esophageal bypass.Strong recommendation, high quality evidence. 2 : ESGE recommends brachytherapy as a valid alternative, alone or in addition to stenting, in esophageal cancer patients with malignant dysphagia and expected longer life expectancy.Strong recommendation, high quality evidence. 3: ESGE recommends esophageal SEMS placement for sealing malignant tracheoesophageal or bronchoesophageal fistulas. Strong recommendation, low quality evidence. 4 : ESGE does not recommend SEMS placement as a bridge to surgery or before preoperative chemoradiotherapy because it is associated with a high incidence of adverse events. Other options such as feeding tube placement are preferable. Strong recommendation, low quality evidence.

BENIGN DISEASE

5: ESGE recommends against the use of SEMSs as first-line therapy for the management of benign esophageal strictures because of the potential for adverse events, the availability of alternative therapies, and their cost. Strong recommendation, low quality evidence. 6: ESGE suggests consideration of temporary placement of self-expandable stents for refractory benign esophageal strictures. Weak recommendation, moderate quality evidence. 7: ESGE suggests that fully covered SEMSs be preferred over partially covered SEMSs for the treatment of refractory benign esophageal strictures because of their very low risk of embedment and ease of removability. Weak recommendation, low quality evidence. 8: ESGE recommends the stent-in-stent technique to remove partially covered SEMSs that are embedded in the esophageal wall. Strong recommendation, low quality evidence. 9: ESGE recommends that temporary stent placement can be considered for the treatment of leaks, fistulas, and perforations. No specific type of stent can be recommended, and the duration of stenting should be individualized. Strong recommendation, low quality of evidence. 10 : ESGE recommends considering placement of a fully covered large-diameter SEMS for the treatment of esophageal variceal bleeding refractory to medical, endoscopic, and/or radiological therapy, or as initial therapy for patients with massive bleeding. Strong recommendation, moderate quality evidence.

A Phase II Study of Biodegradable Stents Plus Palliative Radiotherapy in Oesophageal Cancer

AIMS

Self-expanding metal stents provide rapid improvement of dysphagia in oesophageal cancer but are associated with complications. The aim of the present study was to test the effectiveness of an alternative treatment of combining biodegradable stents with radiotherapy.

MATERIALS AND METHODS

A Simon two-stage single-arm prospective phase II trial design was used to determine the efficacy of biodegradable stents plus radiotherapy in patients with dysphagia caused by oesophagus cancer who were unsuitable for radical treatment. Fourteen patients were recruited and data from 12 were included in the final analyses.

RESULTS

Five of 12 patients met the primary end point: one stent-related patient death; four further interventions for dysphagia within 16 weeks of stenting (41.7%, 95% confidence interval 15.2-72.3%). The median time to a 10-point deterioration of quality of life was 2.7 weeks. Nine patients died within 52 weeks of registration. The median time to death from any cause was 15.0 weeks (95% confidence interval 9.6-not reached).

CONCLUSION

The high re-intervention observed, which met the pre-defined early stopping criteria, meant that the suggested alternative treatment was not sufficiently effective to be considered for a larger scale trial design. Further work is needed to define the place of biodegradable stents in the management of malignant oesophageal strictures.

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.

Nutritional optimization during neoadjuvant therapy prior to surgical resection of esophageal cancer-a narrative review

This narrative review aims to evaluate the evidence for the different nutritional approaches employed during neoadjuvant therapy in patients with locoregional esophageal cancer. Patients with esophageal cancer are often malnourished and difficult to optimize nutritionally. While evidence suggests that neoadjuvant therapy can offer a survival advantage, associated toxicity can exacerbate poor nutritional status. There is currently no accepted standard of care regarding optimal nutritional approach. A systematic literature search was undertaken. Studies describing the utilization of an additional nutritional intervention in patients with esophageal cancer receiving neoadjuvant therapy prior to esophagectomy were included. Primary outcome measure was 30-day postoperative mortality after esophagectomy. Secondary outcome measures were loss of weight during neoadjuvant therapy, completion rate of intended neoadjuvant therapy, complications from nutritional intervention, 30-day postoperative morbidity after esophagectomy and quality of life during neoadjuvant treatment. Given the heterogeneity of retrieved articles results was presented as a narrative review. Twenty-five studies were included of which 16 evaluated esophageal stenting, four feeding jejunostomy, three gastrostomy, one nasogastric feeding, and one comparative study of esophageal stenting to feeding jejunostomy. 30-day postoperative mortality was only reported in two of the 26 included studies limiting comparison between nutritional strategies. All studies of esophageal stents reported improvements in dysphagia with reported weight change ranging from -5.4 to +6 kg and one study reported 30-day postoperative mortality after esophagectomy (10%). In patients undergoing esophageal stenting for their neoadjuvant treatment overall migration rate was 29.9%. Studies of laparoscopically inserted jejunostomy were all retrospective reviews that demonstrated an increase in weight ranging from 0.4 to 11.8 kg and similarly no study reported 30-day postoperative mortality. Only one comparative study was included that compared esophageal stents to jejunostomy. This study reported no significant difference between the two groups in respect to complication rates (stents 22% vs. jejunostomy 4%, P = 0.11) or increase in weight (stents 4.4 kg vs. jejunostomy 4.2 kg, P = 0.59). Quality of life was also poorly reported. This review demonstrates the uncertainty on the optimal nutritional approach for patients with resectable esophageal cancer undergoing neoadjuvant treatment prior to esophagectomy. A prospective, multicenter, observational cohort study is needed to determine current practice and inform a prospective clinical trial.

In-vivo oesophageal regeneration in a human being by use of a non-biological scaffold and extracellular matrix

BACKGROUND

Tissue-engineered extracellular matrix populated with autologous pluripotent cells can result in de-novo organogenesis, but the technique is complex, not widely available, and has not yet been used to repair large oesophageal defects in human beings. We aimed to use readily available stents and extracellular matrix to regenerate the oesophagus in vivo in a human being to re-establish swallowing function.

METHODS

In a patient aged 24 years, we endoscopically placed a readily available, fully covered, self-expanding, metal stent (diameter 18 mm, length 120 mm) to bridge a 5 cm full-thickness oesophageal segment destroyed by a mediastinal abscess and leading to direct communication between the hypopharynx and the mediastinum. A commercially available extracellular matrix was used to cover the stent and was sprayed with autologous platelet-rich plasma adhesive gel. The sternocleidomastoid muscle was placed over the matrix. After 4 weeks, stent removal was needed due to stent migration, and was replaced with three stents telescopically aligned to improve anchoring. The stents were removed after 3·5 years and the oesophagus was assessed by endoscopy, biopsy, endoscopic ultrasonography, and high-resolution impedance manometry.

FINDINGS

After stent removal we saw full-thickness regeneration of the oesophagus with stratified squamous epithelium, a normal five-layer wall, and peristaltic motility with bolus transit. 4 years after stent removal, the patient was eating a normal diet and maintaining a steady weight.

INTERPRETATION

Maintenance of the structural morphology of the oesophagus with off-the-shelf non-biological scaffold and stimulation of regeneration with commercially available extracellular matrix led to de-novo structural and functional regeneration of the oesophagus.

FUNDING

None.

Biodegradable esophageal stents in benign and malignant strictures - a single center experience

BACKGROUND AND STUDY AIMS

Biodegradable (BD) esophageal stents were recently developed mainly for refractory benign strictures, but experience and available literature are limited.

PATIENTS AND METHODS

This was a retrospective observational study. All patients who had BD stents inserted due to refractory benign esophageal strictures or malignant strictures, or were awaiting radical radiotherapy/chemotherapy or neo-adjuvant therapy and esophagectomy between March 2011 and July 2015 were included.

RESULTS

Stent placement was successful in all patients. Ten patients with benign strictures (3 male, median age 80.5 years, IQR: 68.75 - 89.5) were followed-up for a median of 171.5 weeks (IQR: 24 - 177.25). The interval between dilatations prior to the first BD stent placement (median: 34.25 days, IQR: 23.06 - 48.29) was significantly shorter than the interval between the first BD stent placement and the first intervention required (median: 149.5 days, IQR: 94.25 - 209.5) and this difference was statistically significant (P = 0.012). Ten patients with esophageal cancer (8 male, median age: 69 years, IQR: 59.25 - 80.75) were included and they were followed up for a median of 36 weeks (IQR: 26 - 58). Only 1 completed radical radiotherapy successfully, but developed refractory post-radiotherapy stricture. No one proceeded to esophagectomy and 50 % required a self-expanding metal stent (SEMS) at a median of 134 days (IQR: 100 - 263) following stent placement.

CONCLUSIONS

BD stents were successfully deployed in both benign and malignant strictures. They offered a prolonged dilatation-free interval in benign strictures, yet in the majority of patients, strictures recurred. In malignant strictures, stent patency was similar to that of benign strictures, which suggests a potential value in ensuring adequate oral intake during oncologic therapy. In our cohort, however, use of stents did not contribute to improved outcome.

Update on Enteral Stents

The recent advances in enteral stents design and composition introduced novel usage and indications, heading to a continuous addition of prostheses application in clinical practice. Since the first use to palliate malignant diseases, improving patient's quality of life, in the last decades we assisted to a large spread, often becoming a first choice treatment in GI disorders. Indeed, the clinical indication of gastrointestinal stents includes endoscopic treatment of fistula and leaks besides the well-established role of restoring lumen patency in benign and malignant conditions. Several different kind of stents have been developed, each one with its own characteristics and benefits, including self-expandable plastic and metal stents, available as uncovered, partially covered, and fully covered as well as biodegradable stents. Recently, new drug-eluting stents, working both as palliative treatment and as local chemotherapy, are under evaluation. This review aims to critically evaluate the most recently published literature about enteral stents and to address endoscopists' choice for a better patient management.

Polymeric Biodegradable Stent Insertion in the Esophagus

Esophageal stent insertion has been used as a well-accepted and effective alternative to manage and improve the quality of life for patients diagnosed with esophageal diseases and disorders. Current stents are either permanent or temporary and are fabricated from either metal or plastic. The partially covered self-expanding metal stent (SEMS) has a firm anchoring effect and prevent stent migration, however, the hyperplastic tissue reaction cause stent restenosis and make it difficult to remove. A fully covered SEMS and self-expanding plastic stent (SEPS) reduced reactive hyperplasia but has a high migration rate. The main advantage that polymeric biodegradable stents (BDSs) have over metal or plastic stents is that removal is not require and reduce the need for repeated stent insertion. But the slightly lower radial force of BDS may be its main shortcoming and a post-implant problem. Thus, strengthening support of BDS is a content of the research in the future. BDSs are often temporarily effective in esophageal stricture to relieve dysphagia. In the future, it can be expect that biodegradable drug-eluting stents (DES) will be available to treat benign esophageal stricture, perforations or leaks with additional use as palliative modalities for treating malignant esophageal stricture, as the bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.