Stents for colorectal obstruction: Past, present, and future

Malignant Acute Colonic Obstruction: Multidisciplinary Approach for Endoscopic Management

Patients presenting with acute colonic obstruction are usually evaluated in the emergency department and multiple specialties are involved in the patients' management. Pre-treatment evaluation is essential in order to establish the correct endoscopic indication for stent implantation. Contrast-enhanced imaging could allow the exclusion of benign causes of colonic obstruction and evaluation of the length of malignant stricture. Endoscopic stenting is the gold standard of treatment for palliative indications whereas there are still concerns about its use as a bridge to surgery. Different meta-analyses showed that stenting as a bridge to surgery improves short-term surgical outcomes but has no role in improving long-term outcomes. Multidisciplinary evaluation is also essential in patients that may be started on or are currently receiving antiangiogenic agents because endoscopic stenting may increase the risk of perforation. Evidence in the literature is weak and based on retrospective data. Here we report on how to correctly evaluate a patient with acute colonic malignant obstruction in collaboration with other essential specialists including a radiologist, surgeon and oncologist, and how to optimize the technique of endoscopic stenting.

Comparison of Oncological and Perioperative Outcomes Between Self-Expanding Metal Stents and Decompression Tubes for Stages II and III Obstructive Colorectal Cancer: A Retrospective Observational Study

BACKGROUND

A bridge to surgery (BTS) using self-expandable metallic stents (SEMSs) is becoming the primary treatment for obstructive colorectal cancer (OCRC). In Japan, intestinal decompression was usually performed using decompression tubes (DTs). However, few reports have compared the outcomes of SEMS and DTs as BTS. Therefore, we compared the treatment outcomes of SEMS and DTs for OCRC.

METHODS

Data of 80 patients who underwent radical resection after endoscopic decompression for stage II or III OCRC between 2007 and 2021 were retrospectively analyzed. Patients were divided into two groups based on whether they received SEMS (n = 53) or DTs (n = 27).

RESULTS

The clinical success rate of decompression was 96.2% and 88.9% in the SEMS and DT groups, respectively. Additionally, 96.2% of patients who received SEMS were able to resume their routine diet without stricture symptoms. The rate of stoma construction and incidence of postoperative complications were lower in the SEMS group (p < 0.005 and p < 0.01, respectively). The 3-year relapse-free survival rates were 71.9% and 51.2% in the SEMS and DT groups, respectively, which were not significantly different (p = 0.10).

CONCLUSION

BTS using SEMS might be an adequate treatment for stage II or III OCRC regardless of tumor location owing to the comparable oncological outcomes with DT and low perioperative complication rate.

Management of left-sided malignant colorectal obstructions with curative intent: a network meta-analysis

BACKGROUND

Several management options exist for colonic decompression in the setting of malignant large bowel obstruction, including oncologic resection, surgical diversion, and SEMS as a bridge-to-surgery. Consensus has yet to be reached on optimal treatment pathways. The aim of the present study was to perform a network meta-analysis comparing short-term postoperative morbidity and long-term oncologic outcomes between oncologic resection, surgical diversion, and self-expanding metal stents (SEMS) in left-sided malignant colorectal obstruction with curative intent.

METHODS

Medline, Embase, and CENTRAL were systematically searched. Articles were included if they compared two or more of the following in patients presenting with curative left-sided malignant colorectal obstruction: (1) emergent oncologic resection; (2) surgical diversion; and/or (3) SEMS. The primary outcome was overall 90-day postoperative morbidity. Pairwise meta-analyses were performed with inverse variance random effects. Random-effect Bayesian network meta-analysis was performed.

RESULTS

From 1277 citations, 53 studies with 9493 patients undergoing urgent oncologic resection, 1273 patients undergoing surgical diversion, and 2548 patients undergoing SEMS were included. Network meta-analysis demonstrated a significant improvement in 90-day postoperative morbidity in patients undergoing SEMS compared to urgent oncologic resection (OR0.34, 95%CrI0.01-0.98). Insufficient RCT data pertaining to overall survival (OS) precluded network meta-analysis. Pairwise meta-analysis demonstrated decreased five-year OS for patients undergoing urgent oncologic resection compared to surgical diversion (OR0.44, 95%CI0.28-0.71, p < 0.01).

CONCLUSIONS

Bridge-to-surgery interventions may offer short- and long-term benefits compared to urgent oncologic resection for malignant colorectal obstruction and should be increasingly considered in this patient population. Further prospective study comparing surgical diversion and SEMS is needed.

Stenting as a bridge to surgery in obstructing colon cancer: Long-term recurrence pattern and competing risk of mortality

BACKGROUND

Stenting as a bridge to curative surgery (SBTS) for obstructing colon cancer (OCC) has been associated with possibly worse oncological outcomes.

AIM

To evaluate the recurrence patterns, survival outcomes, and colorectal cancer (CRC)-specific death in patients undergoing SBTS for OCC.

METHODS

Data from 62 patients undergoing SBTS at a single tertiary centre over ten years between 2007 and 2016 were retrospectively examined. Primary outcomes were recurrence patterns, overall survival (OS), cancer-specific survival (CSS), and CRC-specific death. OS and CSS were estimated using the Kaplan-Meier curves. Competing risk analysis with cumulative incidence function (CIF) was used to estimate CRC-specific mortality with other cause-specific death as a competing event. Fine-Gray regressions were performed to determine prognostic factors of CRC-specific death. Univariate and multivariate subdistribution hazard ratios and their corresponding Wald test P values were calculated.

RESULTS

28 patients (45.2%) developed metastases after a median period of 16 mo. Among the 18 patients with single-site metastases: Four had lung-only metastases (14.3%), four had liver-only metastases (14.3%), and 10 had peritoneum-only metastases (35.7%), while 10 patients had two or more sites of metastatic disease (35.7%). The peritoneum was the most prevalent (60.7%) site of metastatic involvement (17/28). The median follow-up duration was 46 mo. 26 (41.9%) of the 62 patients died, of which 16 (61.5%) were CRC-specific deaths and 10 (38.5%) were deaths owing to other causes. The 1-, 3-, and 5-year OS probabilities were 88%, 74%, and 59%; 1-, 3-, and 5-year CSS probabilities were 97%, 83%, and 67%. The highest CIF for CRC-specific death at 60 mo was liver-only recurrence (0.69). Liver-only recurrence, peritoneum-only recurrence, and two or more recurrence sites were predictive of CRC-specific death.

CONCLUSION

The peritoneum was the most common metastatic site among patients undergoing SBTS. Liver-only recurrence, peritoneum-only recurrence, and two or more recurrence sites were predictors of CRC-specific death.

Oncologic impact of colonic stents for obstructive left-sided colon cancer

Colonic stenting has had a significant positive impact on the management of obstructive left-sided colon cancer (OLCC) in terms of both palliative treatment and bridge-to-surgery (BTS). Notably, many studies have convincingly demonstrated the effectiveness of stenting as a BTS, resulting in improvements in short-term outcomes and quality of life, safety, and efficacy in subsequent curative surgery, and increased cost-effectiveness, whereas the safety of chemotherapy after stenting and the long-term outcomes of stenting as a BTS are controversial. Several studies have suggested an increased risk of perforation in patients receiving bevacizumab chemotherapy after colonic stenting. In addition, several pathological analyses have suggested a negative oncological impact of colonic stenting. In contrast, many recent studies have demonstrated that colonic stenting for OLCC does not negatively impact the safety of chemotherapy or long-term oncological outcomes. The updated version of the European Society of Gastrointestinal Endoscopy guidelines released in 2020 included colonic stenting as a BTS for OLCC as a recommended treatment. It should be noted that the experience of endoscopists is involved in determining technical and clinical success rates and possibly oncological outcomes. This review discusses the positive and negative impacts of colonic stenting on OLCC treatment, particularly in terms of oncology.

The clinical outcomes of the radiologic method for self-expandable metal-stent placement in patients with colorectal obstruction: A prospective study

OBJECTIVES

To assess the clinical outcomes of self-expandable metal stent (SEMS) placement for patients with colorectal obstruction.

METHODS

A total of 61 patients underwent SEMS placement using computerized tomography (CT) to confirm malignancy of intrinsic origin and evaluate the exact location, notch, and extent of the disruptive laceration.

RESULTS

The overall technical success rate and clinical success rate of SEMS placement using the radiological method were 59 (96.7%) and 57 (93.4%), respectively. The technical success rate and clinical success rate of SEMS placement in the palliative and bridge to elective surgery (BTS) groups were 35 (97.2%), 24 (96.0%), 33 (91.7%), and 24 (96.0%). The median cumulative primary stent patency duration and patients' survival of SEMS placement was 123 days (95% CI, 65-123 days), and 133 days (95% CI, 72-133 days). The median cumulative primary stent patency duration and patient survival did not differ significantly between the palliative group 119 days; (95% CI, 59-119 days), 128 days; (95% CI, 71-128 days), and the BTS group 120 days; (95% CI, 68-120 days; p = 0.362), 130 days; (95% CI, 78-130 days); p = 0.412).

CONCLUSIONS

The colorectal obstruction had convoluted with curved angulation and located mainly at the rectum, sigmoid, descending colon, and the radiologic method of SEMS placement has more efficacious with a high technical and clinical success rate. However, SEMS placement was highly technical, and clinical success with median stent patency and patient survival did not differ significantly between the palliative group and the BTS group.

Structural optimization and in vivo evaluation of a colorectal stent with anti-migration and anti-tumor properties

Clinically, colorectal stents can only palliatively relieve obstruction caused by colorectal cancer (CRC), with a high incidence of stent migration and tumor-related re-obstruction. To overcome these shortcomings, we developed a colorectal stent composed of a structure-optimized nitinol braided stent and a tubular film including an inner layer of poly (ethylene-co-vinyl acetate) (EVA) and a segmental outer layer of EVA with paclitaxel (PTX). The braiding pattern, segment number, and end shape of the stent were optimized based on the mechanical properties, ex vivo and in vivo anti-migration performance, and tissue response of the stent. The optimized nitinol stent had a structure of one middle segment in a hook-pattern and two end segments in a cross-pattern with two studs on each end in a staggered arrangement. Structure-optimized colorectal stents were prepared and evaluated in vivo. PTX released from the stent was mostly distributed in the rabbit rectum in contact with it. The biosafety of the colorectal stent was evaluated using blood tests, biochemical analysis, anatomical observation, and pathological analysis. The anti-tumor effect of the stent was also evaluated by endoscopy, anatomical observation, and pathological and immunohistochemical analyses in rabbits with orthotopic CRC. The results demonstrate that the optimized colorectal stents have effective anti-migration ability and anti-tumor effects with good biosafety. STATEMENT OF SIGNIFICANCE: In order to overcome the most common disadvantages of migration and re-obstruction of colorectal stents clinically, a colorectal stent composed of a structure-optimized nitinol stent and a tubular film including an inner layer of EVA and a segmental outer layer of EVA with PTX was put forward in this study. The optimized nitinol stent had a structure of one middle segment in hook-pattern and two end segments in cross-pattern with two studs on each end in staggered arrangement. The resulting colorectal stent has been proved with good anti-migration ability, anti-tumor effects, and biosafety in vivo, which provides a safe and effective potential treatment modality for patients with colorectal cancer.

Intestinal stents: Structure, functionalization and advanced engineering innovation

Intestinal stents are a palliative treatment option that solves many shortcomings of traditional surgeries for cancer-induced intestinal obstructions. The present review provides an overview of the incidence, clinical manifestations and limitations in the treatment of intestinal cancers. The paper also discusses material property requirements, indications, complications and the future of stent-assisted therapy. The advantages and disadvantages of different materials and processing techniques for intestinal stents are reviewed along with new stent treatment combinations for colorectal cancer. Challenges that require further cooperative studies are also detailed. The future development of intestinal stents will depend on innovation in material designs as well as the utilization of multi-functional strategies and innovative engineering solutions.

Futuristic Developments and Applications in Endoluminal Stenting

Endoscopic stenting is a well-established option for the treatment of malignant obstruction, temporary management of benign strictures, and sealing transmural defects, as well as drainage of pancreatic fluid collections and biliary obstruction. In recent years, in addition to expansion in indications for endoscopic stenting, considerable strides have been made in stent technology, and several types of devices with advanced designs and materials are continuously being developed. In this review, we discuss the important developments in stent designs and novel indications for endoluminal and transluminal stenting. Our discussion specifically focuses on (i) biodegradable as well as (ii) irradiating and drug-eluting stents for esophageal, gastroduodenal, biliary, and colonic indications, (iii) endoscopic stenting in inflammatory bowel disease, and (iv) lumen-apposing metal stent.

Metallic stent insertion to relieve malignant bowel obstruction in a child: a case report

Self-expandable metallic stents (SEMS) have been widely used in adults to relieve obstruction secondary to colorectal tumours. However, there is a paucity of literature about their use in children, with only a few case reports describing stent insertion in children with benign colonic conditions. There is one case report on a malignant colonic condition in a child by Hussain et al. in the literature. However, due to the rarity of the condition, there are currently no guidelines from learned societies on colorectal SEMS placement in paediatric patients. We share our experience of using a fully covered SEMS to relieve malignant colonic obstruction in a 6 year-old-child, who was on treatment for T cell lymphoma. This was done as a bridge to surgery, thereby allowing planned surgery, and avoiding colostomy in this child, who went on to have colonic resection with primary anastomosis.

Localized Photothermal Ablation Therapy of Obstructive Rectal Cancer Using a Nanofunctionalized Stent in a Mouse Model

The self-expanding metal stent (SEMS) is a versatile, palliative treatment method for unresectable, malignant, non-vascular strictures. Colorectal cancer (CRC) is one of the candidates for the application of the SEMS, in combination with the photothermal ablation (PTA) technique that enhances its therapeutic efficacy. The objective of this study was to investigate the efficacy of stent-mediated PTA therapy in an endoscopy-guided, orthotopic rectal cancer model. A total of 30 of 40 mice with the tumor size of grade 4 were included and were divided into three groups of 10 mice each. Group A underwent a gold nanoparticle (AuNP)-coated SEMS but no near-infrared (NIR) irradiation, group B received an uncoated control SEMS with NIR irradiation, and group C received a AuNP-coated SEMS and NIR irradiation together. Colonoscopy and in vivo imaging, immunohistochemical analysis, and quantitative reverse-transcription polymerase chain reaction of major tumor markers were performed. Stent placement and PTA were technically successful using colonoscopy. The tumor grade reduction after PTA is significant in group C, compared with groups A or B (p < 0.001). Molecular analysis validated this observation with a significantly reduced Mapk1 proliferation marker or increased Jnk expression. Histological analysis confirmed the localized PTA therapy using AuNP-coated SEMS profoundly ablated tumor outgrowth through the stent. Our results indicate that this novel strategy of localized PTA therapy could be a promising option for palliative treatment of CRC and to support prolonged stent patency with a decreased tumor volume.

Colon stenting in benign diverticular stricture - a case report and review of literature

Background: Colonic stricture is a feared complication with varied etiology ranging from malignant obstruction to benign diseases. One such condition is recurrent diverticulitis-related strictures. Objectives & Methods: We report a case of a 48-year-old male patient with stricture of the sigmoid colon. The patient refused Sigmoid colon resection. He underwent stent placement and Two weeks later presented with constipation and abdominal discomfort. On Computed Tomography (CT) we discovered stent migration and consequent large bowel obstruction. Patient agreed on undergoing sigmoidectomy with a colostomy. Conclusion: Indication of SEMS for benign lesions remains unclear. Based on the current data, in benign colorectal obstructive lesions, SEMS is a viable option as a bridge to surgery when no other alternative option is available. However, the ASCRS 2020 guidelines did not point to SEMS as an option given the high rate of complications. Our patient was treated with a stent because he refused the resection surgery and found relief for a certain period before developing stent migration. Hence, the patients should be educated about the short and long-term potential effects of stenting before performing the procedure in benign strictures.

Prognostic Value of Neutrophil-to-Lymphocyte Ratio in Obstructing Colorectal Cancer Treated by Endoscopic Stenting as a Bridge to Surgery

Purpose

Neutrophil-to-lymphocyte ratio (NLR) has been reported to predict adverse survival outcomes among patients with colorectal cancer (CRC). This study evaluates the prognostic value of NLR among patients with obstructing CRC who successfully underwent stenting before curative surgery.

Methods

We retrospectively reviewed patients who underwent stenting before surgery. Patient demographics, tumor characteristics, perioperative outcomes, recurrence-free survival (RFS), and overall survival (OS) were analyzed. NLR was calculated from the differential white blood cell counts at least 4 days after successful stenting, before elective surgery. Optimal cutoff to dichotomize NLR was obtained by maximizing log-rank test statistic with recursive partitioning of Kaplan-Meier RFS and OS curves. The optimal cutoff for high NLR was ≥ 5 at presentation before stenting, and ≥ 4 after stenting.

Results

Fifty-seven patients with localized obstructing CRC underwent successful endoscopic stenting before curative surgery. High NLR was associated with lymphovascular invasion (P = 0.006) and apical lymph node involvement (P = 0.034). Major perioperative complication(s) (hazard ratio [HR], 11.34; 95% confidence interval [CI], 2.49 to 51.56; P < 0.01) and high NLR (HR, 3.69; 95% CI, 1.46 to 9.35; P < 0.01) negatively impacted OS on univariate and multivariate analyses. High NLR negatively impacted RFS on univariate analysis (HR, 2.91; 95% CI, 1.29 to 6.60; P = 0.01).

Conclusion

NLR of ≥ 4 after stenting is an independent prognostic factor among patients with obstructing localized CRC who are successfully decompressed by endoscopic stenting before curative surgery.

Colonic Stent Use by Indication and Patient Outcomes: A Nationwide Inpatient Sample Study

BACKGROUND

Colonic stent placement can avoid urgent surgery for large bowel obstruction in selected patients. Population-wide stent utilization patterns and outcomes are unknown.

MATERIALS AND METHODS

Using retrospective, population-based, Nationwide Inpatient Sample data, we studied patients with colonic stents discharged during 2010-2015. The primary outcome was ostomy creation during the same hospitalization. Other outcomes were perforation or peritonitis, and in-hospital death. Associations of outcomes with stent indication were investigated, adjusting for patient-, admission-, and hospital characteristics. We estimated annual population-wide stent use volumes.

RESULTS

Of 4257 patients with stent placement (52% male, mean age 64.6 years), 9.9% had non-metastatic colon cancer, 12.9% metastatic colon cancer, 37.8% extracolonic malignancy (ECM), and 39.3% had benign obstruction. In 8.1% of patients, ostomy creation surgery was performed. Perforation or peritonitis occurred in 16.7%, and in-hospital death in 4.5%. Relative to ECM, ostomy creation was several-fold more likely among nonmetastatic colon cancer (adjusted odds ratio (OR) 3.4; 95%CI, 2.1-5.5), metastatic colon cancer (adjusted OR 2.5; 95%CI, 1.7-3.7), and benign obstruction patients (adjusted OR 3.1; 95%CI, 2.1-4.7). Benign obstruction was associated with high risk of perforation/peritonitis (adjusted OR 3.1 relative to non-metastatic CC (95%CI, 2.1-4.5)). Perforation/peritonitis was highly associated with inpatient death (adjusted OR 6.8 (95%CI, 4.9-9.5)). Annually, about 3,580 patients underwent stent placement, with benign obstruction showing an increasing trend (P=0.0002).

CONCLUSIONS

Over 75% of stent placements were done for patients with benign disease and ECM obstruction. Subsequent ostomy creation during the hospitalization was least likely among ECM patients. Rates of perforation/peritonitis in benign obstructions were concerningly high. (22.2%).

Colonic Stenting in the Emergency Setting

Nowadays, colorectal cancer (CRC) is the third most frequent cancer, and about a third of patients with CRC presents themselves with symptoms of large bowel obstruction. Historically, surgical resection was the treatment of choice for colonic obstruction, but this kind of approach is burdened by a high risk of postoperative morbidity and mortality. In recent times, the use of a colonic stent has been proposed to overcome the obstruction and transform an emergency surgical case into an elective one to avoid emergency surgery complications. Endoscopic stenting is the first-line treatment option in the palliative management of colonic obstruction, and there is sufficient scientific evidence to support this approach. However, endoscopic stent used as a bridge to surgery is not yet widely adopted because the concern was raised about the long-term survival and cancer safety of this approach. The recent scientific evidence has shown that this approach improves the short-term outcomes, such as postoperative complications and the stoma rate, without differences in long-term outcomes compared to emergency surgery. Therefore, the European Society for Gastrointestinal Endoscopy in 2020 has reconsidered stenting as a bridge to surgery as a valid alternative to emergency surgery.

Development and In Vitro Evaluation of 5-Fluorouracil-Eluting Stents for the Treatment of Colorectal Cancer and Cancer-Related Obstruction

Self-expanding metal stents (SEMSs) are currently the gold standard for the localised management of malignant gastrointestinal (GI) stenosis and/or obstructions. Despite encouraging clinical success, in-stent restenosis caused by tumour growth is a significant challenge. Incorporating chemotherapeutic drugs into GI stents is an emerging strategy to provide localised and sustained release of drugs to intestinal malignant tissues to prevent tumour growth. Therefore, the aim of this work was to develop and evaluate a local GI stent-based delivery system that provides a controlled release of 5-fluorouracil (5FU) over a course of several weeks to months, for the treatment of colorectal cancer and cancer-related stenosis/obstructions. The 5FU-loaded GI stents were fabricated via sequential dip-coating of commercial GI stents with a drug-loaded polyurethane (PU) basecoat and a drug-free poly(ethylene-co-vinyl acetate) (PEVA) topcoat. For comparison, two types of commercial stents were investigated, including bare and silicone (Si) membrane-covered stents. The physicochemical properties of the 5FU-loaded stents were evaluated using photoacoustic Fourier-transform infrared (PA-FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and thermal analysis. In vitro release studies in biological medium revealed that the 5FU-loaded stents provided a sustained release of drug over the period studied (18 d), and cell viability, cell cycle distribution and apoptosis assays showed that the released 5FU had comparable anticancer activity against human colon cancer cells (HCT-116) to pure 5FU. This study demonstrates that dip-coating is a facile and reliable approach for fabricating drug-eluting stents (DESs) that are promising candidates for the treatment of GI obstructions and/or restenosis.

Uncovered self-expandable metal stents for the treatment of refractory benign colorectal anastomotic stricture

Self-expandable metal stent (SEMS) placement has been suggested as a therapeutic modality for treating benign colorectal strictures. Covered stents are generally used, given the concerns regarding the efficacy and safety of uncovered stents. Hence, few studies have evaluated the efficacy and safety of uncovered SEMSs (UCSEMSs) in patients with refractory benign colorectal anastomotic strictures. In this study, 12 patients with postoperative benign symptomatic anastomotic strictures refractory to pneumatic dilation (range, 2–9) and transient indwelling-covered SEMSs were treated using UCSEMS. All enrolled patients were men (mean age, 61 years). Stent placement was successful in all 12 patients, and early clinical success was achieved in 11 (92%) patients. Four patients (25%) showed successful clinical outcomes without further intervention, but eight patients (75%) were clinically unsuccessful, and showed stricture recurrence or functional obstructive symptoms. Three patients underwent surgery, and the remaining five patients required repeat stent procedures. Despite the high reobstruction rate, the median follow-up period after UCSEMS placement was 16.7 months, demonstrating that UCSEMS may be able to achieve medium-term symptom relief without any complications. Therefore, UCSEMS may be an alternative option in exceptional circumstances in carefully selected patients, where invasive surgical treatments, such as stoma diversion, are not an option, thereby improving patients’ quality of life.

Obstructing Left-Sided Colonic Cancer: Is Endoscopic Stenting a Bridge to Surgery or a Bridge to Nowhere?

For the 8-29% colorectal cancers that initially manifest with obstruction, emergency surgery (ES) was traditionally considered the only available therapy, despite high morbidity and mortality rates and the need for colostomy creation. More recently, malignant obstruction of the left colon can be temporized by endoscopic placement of a self-expanding metallic stent (SEMS), used as bridge to surgery (BTS), facilitating a laparoscopic approach and increasing the likelihood that a primary anastomosis instead of stoma would be used. Despite these attractive outcomes, the superiority of the BTS approach is not clearly established. Few authors have stressed the potential cancer risk associated with perforations that may occur during endoscopic stent placement, facilitating neoplastic spread and negatively impacting prognosis. For this reason, the current literature focuses on long-term oncologic outcomes such as disease-free survival, overall survival and recurrence rate that do seem not to differ between the ES and BTS approaches. This lack of consensus has spawned differing and sometimes discordant guidelines worldwide. In conclusion, 20 years after the first description of a colonic stent as BTS, the debate is still open, but the growing number of articles about the use of SEMS as a BTS signifies a great interest in the topic. We hope that these data will finally converge on a single set of recommendations supporting a management strategy with well-demonstrated superiority.

Efficacy of uncovered self-expandable metallic stent for colorectal obstruction by extracolonic malignancy

BACKGROUND

Self-expandable metallic stent (SEMS) is widely used for malignant colorectal obstruction. Recently, SEMS has been used for palliative option for colorectal obstruction caused by extracolonic malignancy (ECM).

AIM

To evaluate the efficacy of SEMS for colorectal obstruction caused by ECM, and to identify the factors associated with stent occlusion.

METHODS

Seventy-two patients who were treated with uncovered SEMS insertion for malignant colorectal obstructions caused by colorectal metastasis or peritoneal seeding of ECM at Samsung Medical Center between April 2012 to March 2016 were enrolled. We analyzed technical and clinical outcomes of stent insertion, the factors associated with stent occlusion and long term outcomes after stent insertion.

RESULTS

Technical success rate was determined as 90.3% with a clinical success rate of 87.7%. Stent occlusion developed in 28.1%, with a median duration of 51 d. Further, 81.3% with stent occlusion could be treated with secondary stent insertion. Clinical failure was observed to be related to the male sex (P = 0.020) and right colon obstruction (P = 0.017). Stent length ≤ 10 cm was found to be associated with stent occlusion (P = 0.003). Median survival time after stent insertion was 4.7 mo and 40.4% were able to receive their oncological treatments after stent insertion without surgery.

CONCLUSION

Uncovered SEMS is effective for the treatment of colorectal obstruction caused by ECM, considering life expectancy of patients with ECM.

Stenting as a Bridge to Surgery or a Palliative Treatment

Endoscopic stenting of the colorectum has emerged as a viable alternative to surgical interventions in a selected group of patients. The main indication for stenting is bowel obstruction. As such stenting can be used to palliate patients with metastatic disease or bridge patients to surgical intervention. The main advantages of stenting in the emergency setting include lower morbidity and mortality, lower incidence of stoma formation, shorter hospitalization, and better quality of life. For patients with unresectable disease and short life expectancy, stenting can be considered. However, for patients with longer life expectancy, the potential long-term complications of a metal stent such as erosion, migration, or obstruction have engendered debate whether such patients are better served by operative intervention. Stenting as a bridge to surgery is an alternative to surgery in patients who are high risk for emergency surgery but concerns remain regarding its impact on oncologic outcome in potentially curable patients.

Cost-effectiveness of palliative emergent surgery versus endoscopic stenting for acute malignant colonic obstruction

BACKGROUND

Endoscopic stenting has demonstrated value over emergent surgery as a palliative intervention for patients with acute large bowel obstruction due to advanced colorectal cancer. However, concerns regarding high reintervention rates and the risk of perforation have brought into question its cost-effectiveness.

METHODS

A decision tree analysis was performed to analyze costs and survival in patients with unresectable or metastatic colorectal cancer who present with acute large bowel obstruction. The model was designed with two treatment arms: self-expanding metallic stent (SEMS) placement and emergent surgery. Costs were derived from medicare reimbursement rates (US$), while effectiveness was represented by quality-adjusted life years (QALYs). The primary outcome measure was the incremental cost-effectiveness ratio (ICER). The model was tested for validation using one-way, two-way, and probabilistic sensitivity analyses.

RESULTS

Endoscopic stenting resulted in an average cost of $43,798.06 and 0.68 QALYs. Emergent surgery cost $5865.30 more, while only yielding 0.58 QALYs. This resulted in an ICER of - $58,653.00, indicating that SEMS placement is the dominant strategy. One-way and two-way sensitivity analyses demonstrated that emergent surgery would require an improved survival rate in comparison to endoscopic stenting to become the favored treatment modality. In 100,000 probabilistic simulations, endoscopic stenting was favored 96.3% of the time.

CONCLUSIONS

In patients with acute colonic obstruction in the presence of unresectable or metastatic disease, endoscopic stenting is a more cost-effective palliative intervention than emergent surgery. This recommendation would favor surgery over SEMS placement with improved surgical survival, or if the majority of patients undergoing stenting required reintervention.

Influence of Polymer Composition on the Controlled Release of Docetaxel: A Comparison of Non-Degradable Polymer Films for Oesophageal Drug-Eluting Stents

Following the huge clinical success of drug-eluting vascular stents, there is a significant interest in the development of drug-eluting stents for other applications, such as the treatment of gastrointestinal (GI) cancers. Central to this process is understanding how particular drugs are released from stent coatings, which to a large extent is controlled by drug-polymer interactions. Therefore, in this study we investigated the release of docetaxel (DTX) from a selection of non-degradable polymer films. DTX-polymer films were prepared at various loadings (1, 5 and 10% w/w) using three commercially available polymers including poly(dimethylsiloxane) (PSi), poly (ethylene-co-vinyl acetate) (PEVA) and Chronosil polyurethane (PU). The formulations were characterised using different techniques such as photoacoustic Fourier-transform infrared (PA-FTIR) spectrophotometry, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of DTX on the mechanical properties of the films, in-vitro release, and degradation tests were also assessed. For all polymers and DTX loadings, the drug was found to disperse homogenously without crystallisation within the polymer matrix. While no specific interactions were observed between DTX and PSi or PEVA, hydrogen-bonding appeared to be present between DTX and PU, which resulted in a concentration-dependent decrease in the Young’s moduli of the films due to disruption of inter-polymeric molecular interactions. In addition, the DTX-PU interactions were found to modulate drug release, providing near-linear release over 30 days, which was accompanied by a significant reduction in degradation products. The results indicate that DTX-loaded PU films are excellent candidates for drug-eluting stents for the treatment of oesophageal cancer.

Stent Placement for Palliative Treatment of Malignant Colorectal Obstruction: Extracolonic Malignancy Versus Primary Colorectal Cancer

OBJECTIVE. The purpose of this study is to compare the clinical outcomes of stent placement for the palliative treatment of colorectal obstruction in patients with extracolonic malignancy (ECM) versus those with primary colorectal cancer (CRC) and to identify the risk factors for stent failure. MATERIALS AND METHODS. Between January 2005 and December 2017, a total of 85 patients underwent stent placement for the palliative treatment of inoperable malignant colorectal obstructions caused by ECM (n = 56) or CRC (n = 29). Technical and clinical success, reintervention rates, and stent patency were compared between the two groups. Predictive factors associated with stent failure were identified. RESULTS. Stent placement was technically successful in 54 patients with ECM (96.4%) and 27 patients with CRC (93.1%) (p = 0.60). The proportion of patients with ECM who required reintervention was greater than that of patients with CRC (20.4% vs 3.7%, respectively; p = 0.04); however, they had a marginally lower clinical success rate (88.9% vs 100.0%, respectively; p = 0.07). The 6- and 12-month stent patency rates were 64.2% and 22.0%, respectively, in patients with ECM and 68.4% and 31.3%, respectively, in patients with CRC (p = 0.89). Long obstructions (hazard ratio, 1.40) and multiple obstructions (hazard ratio, 4.03) were independent factors associated with stent failure. CONCLUSION. Stent placement for the palliative treatment of colorectal obstruction is less effective and more frequently requires reintervention in patients with ECM than in patients with CRC. Long obstructions and multiple obstructions were associated with stent failure.

Nitinol thin films functionalized with CAR-T cells for the treatment of solid tumours

Micropatterned nickel titanium (commonly known as nitinol) thin films with complex designs, high structural resolution and excellent biocompatibility can be cheaply fabricated using magnetron sputtering. Here, we show that these benefits can be leveraged to fabricate micromesh implants that are loaded with tumour-specific human chimeric antigen receptor (CAR)-T cells for the treatment of solid tumours. In a mouse model of non-resectable ovarian cancer, the cell-loaded nitinol thin films spatially conformed to the implantation site, fostered the rapid expansion of T cells, delivered a high density of T cells directly to the tumour and significantly improved animal survival. We also show that self-expandable stents that were coated with T-cell-loaded films and implanted into subcutaneous tumours in mice improved the duration of stent patency by delaying tumour ingrowth. By providing direct access to tumours, CAR-T-cell-loaded micropatterned nitinol thin films can improve the effects of cell-based therapies.

Endoscopic stenting in colorectal cancer

Acute malignant large bowel obstruction presents as one of the few emergencies of colorectal cancer (CRC). Management of this condition can either be by (I) upfront surgery or (II) the use of self-expanding metallic stent (SEMS) as a bridge to elective surgery. For patients with metastasis, the use of SEMS is reported to enable earlier commencement of chemotherapy. Although the use of SEMS in patients with acute malignant large bowel obstruction looks promising, it is plagued by its own set of complications and divided opinion over its long-term outcomes. Conflicting data are present, and definitive indication requires further evaluation and debate. This article will describe the typical presentation of patients with acute malignant large bowel obstruction. An introduction to the SEMS insertion procedural steps will be undertaken. Following which the article aims to review the safety profile of SEMS and the short- and long-term outcomes of SEMS in both the curative and palliative setting.

Colonic stents for malignant bowel obstruction: current status and future prospects

Introduction: Although more than two decades are already passed from the first description of this technique, the debate remains open on the role of self-expanding metal stents (SEMS) placement in the management of malignant bowel obstruction (MBO). According to most recent data, SEMS placement is considered a safe and effective alternative treatment as a bridge to surgery(BTS). In addition, stent placement should be considered as primary option for palliative treatment of obstructing cancer.Areas covered: Current status, indication, technique, oncological outcomes, advantages, and risks of SEMS placement in MBO were reviewed.Expert commentary: The placement of colonic SEMS for palliation and for BTS in patients with MBO has been increasingly reported and it seems to have several advantages over emergency surgery. Substantial concerns of tumor seeding following SEMS placement, especially in case of perforation, have been raised in numerous studies. Actually, no significant differences are reported in oncologic long-term survival between patients undergoing stent placement as a BTS and those undergoing emergency surgery. Considering all the mentioned factors, indication for colorectal stenting should be evaluated only in highly specialized centers, in the context of multidisciplinary approach where risks and benefits of stenting are carefully weighed, especially in the BTS setting.

Endoscopic Management of Benign Colonic Obstruction and Pseudo-Obstruction

There are a variety of causes of intestinal obstruction, with the most common cause being malignant diseases; however, volvulus, inflammatory bowel disease or diverticulitis, radiation injury, ischemia, and pseudo-obstruction can also cause colonic obstruction. These are benign conditions; however, delayed diagnosis of acute intestinal obstruction owing to these causes can cause critical complications, such as perforation. Therefore, high levels of clinical suspicion and appropriate treatment are crucial. There are variable treatment options for colonic obstruction, and endoscopic treatment is known to be a less invasive and an effective option for such. In this article, the authors review the causes of benign colonic obstruction and pseudo-obstruction and the role of endoscopy in treating them.

Fluoroscopic Rescue of Failed Endoscopic Stent Placement for Obstructing Colorectal Malignancy

OBJECTIVE. This study evaluated the technical feasibility and clinical effectiveness of fluoroscopic stent placement in malignant colorectal obstructions after failed endoscopic stent placement. MATERIALS AND METHODS. Between January 2004 and December 2017, 41 patients with malignant colorectal obstructions were referred for fluoroscopic stent placement after failed endoscopy. The procedures were performed for palliation (n = 35) or as a bridge to surgery (n = 6). The technical and clinical success, complications, stent patency duration, and patient survival were retrospectively analyzed. RESULTS. Fluoroscopic stent placement was technically successful in 38 patients (92.7%). The causes of technical failure were complete obstruction (n = 1), redundant sigmoid colon (n = 1), and colon perforation (n = 1). Clinical success was achieved in 37 patients with technical success (97.4%). Major complications occurred in three patients (7.9%) and included colon perforation (n = 2) and anal pain (n = 1). The six patients with stenting as a bridge to surgery underwent elective colectomy uneventfully (100%). In 32 patients with technically successful palliative stenting, the median primary stent patency duration and patient survival were 353 days (95% CI, 162-353 days) and 335 days (95% CI, 116-335 days), respectively. CONCLUSION. Fluoroscopic colorectal stent placement is technically feasible and clinically effective in most patients with failed endoscopic procedures.

Efficacy of intestinal obstruction stent combined with laparoscopic surgery and neoadjuvant chemotherapy in patients with obstructive colorectal cancer

There is still controversy on the surgical treatment of obstructive colorectal cancer worldwide. No accurate research has been reported to propose which method is the most suitable for patients with obstructive colorectal cancer. Therefore, comparison of efficacy of intestinal stent and trans-anal ileus catheter combined with laparoscopic surgery and neoadjuvant chemotherapy respectively in patients with obstructive colorectal cancer was carried out to provide reference and guidance for the selection of surgical schemes for patients with obstructive colorectal cancer. In total 89 patients with obstructive colorectal cancer treated in the Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, from February 2016 to March 2017 were selected for retrospective analysis. Forty-nine cases treated with intestinal metal stent implantation combined with laparoscopic surgery and neoadjuvant chemotherapy were the stent group. The other 40 cases treated with trans-anal ileus catheter combined with laparoscopic surgery and neoadjuvant chemotherapy were the catheter group. The intestinal preparation time, surgical duration, intraoperative blood loss, open surgery rate, postoperative exhaust time and adverse reaction rate were compared between the two groups. All the patients were followed up with reexamination at 1 year in hospital to record the local recurrence rate and tumor implantation rate of incision. The intestinal preparation time in the stent group was shorter than that in the catheter group (P<0.001). The surgical duration in the stent group was longer than that in the catheter group (P<0.001). The intraoperative blood loss in the stent group was higher than that in the catheter group (P<0.001). However, there was no significant difference in open surgery rate, postoperative exhaust time, adverse reaction rate, local recurrence rate or incision tumor implantation rate between the two groups (all P>0.05). Therefore, intestinal metal stent implantation can effectively relieve intestinal obstruction, while trans-anal ileus catheter has higher safety in laparoscopic surgery. Their combination with neoadjuvant chemotherapy and laparoscopic surgery for obstructive colorectal cancer has high value and clinical effect. The best treatment plan should be selected according to the patient's condition.

Uncovered versus covered stent in management of large bowel obstruction due to colorectal malignancy: a systematic review and meta-analysis

PURPOSE

To compare outcomes of uncovered stent and covered stent in management of large bowel obstruction secondary to colorectal malignancy.

METHODS

We conducted a search of electronic databases identifying studies comparing outcomes of uncovered and covered stents in management of large bowel obstruction secondary to colorectal malignancy. The Cochrane risk-of-bias tool and the Newcastle-Ottawa scale were used to assess the included studies. Random or fixed effects modelling were applied as appropriate to calculate pooled outcome data.

RESULTS

One randomised controlled trial (RCT) and nine observational studies, enrolling 753 patients, were identified. Uncovered stent was associated with lower risks of complications (RR 0.57 95% CI 0.44-0.74, P < 0.0001), tumour overgrowth (RR 0.29 95% CI 0.09-0.93, P = 0.04), and stent migration (RR 0.29 95% CI 0.17-0.48, P < 0.00001); longer duration of patency (MD 18.47 95% CI 10.46-26.48, P < 0.00001); lower need for stent reinsertion (RR 0.38 95% CI 0.17-0.86, P = 0.02); and higher risk of tumour ingrowth (RR 4.53 95% CI 1.92-10.69, P = 0.0008). Rates of technical success (RR 1.02 95% CI 0.99-1.04, P = 0.21), clinical success (RR 1.03 95% CI 0.98-1.08, P = 0.32), perforation (RD 0.01 95% CI - 0.03-0.02, P = 0.65), bleeding (RD 0.00 95% CI - 0.03-0.03, P = 0.98), stool impaction (RR 0.56 95% CI 0.12-2.04, P = 0.38) and stent obstruction (RR 2.23 95% CI 0.94-5.34, P = 0.97) were similar.

CONCLUSIONS

Our results suggest that uncovered stents are superior as indicated by fewer complications, lower rates of stent migration, longer duration of patency and a reduced need for stent reinsertion. The best available evidence is mainly derived from non-randomised studies; there is a need for more RCTs.

Short-term outcomes of a self-expandable metallic stent as a bridge to surgery vs. a transanal decompression tube for malignant large-bowel obstruction: a meta-analysis

PURPOSE

Preoperative intestinal decompression, using either a self-expandable metallic stent (SEMS) as a bridge to surgery (BTS) or a transanal decompression tube (TDT), provides an alternative to emergency surgery for malignant large-bowel obstruction (MLBO). We conducted this meta-analysis to compare the short-term outcomes of SEMS placement as a BTS vs. TDT placement for MLBO.

METHODS

We conducted a comprehensive electronic search of literature published up to March, 2018, to identify studies comparing the short-term outcomes of BTS vs. TDT. Decompression device-related and surgery-related variables were evaluated and a meta-analysis was performed using random-effects models to calculate odd ratios with 95% confidence intervals.

RESULTS

We analyzed 14 nonrandomized studies with a collective total of 581 patients: 307 (52.8%) who underwent SEMS placement as a BTS and 274 (47.2%) who underwent TDT placement. The meta-analyses showed that the BTS strategy conferred significantly better technical and clinical success, helped to maintain quality of life by allowing free food intake and temporal discharge, promoted laparoscopic one-stage surgery without stoma creation, and had equivalent morbidity and mortality to TDT placement.

CONCLUSIONS

Although the long-term outcomes are as yet undetermined, the BTS strategy using SEMS placement could be a new standard of care for preoperative decompression to manage MLBO.

[Effectiveness of various approaches for acute malignant colonic obstruction]

AIM

To determine optimal treatment strategy for acute malignant colonic obstruction.

MATERIAL AND METHODS

349 patients with acute malignant colonic obstruction were retrospectively analyzed for the period 2005-2017. All patients were divided into two groups depending on surgical approach. Surgical group comprised 259 patients, endoscopic group - 90 patients. Both groups were comparable by gender, age, level of intestinal obstruction and duration of the disease. However, morbidity and mortality rate were significantly different.

RESULTS

In surgical group incidence of complications was 63.3%, mortality - 19.7%. In group of endoscopic stenting the same values were 8.9% and 6.7%, respectively. Significant differences of morbidity and mortality were observed between groups (p<0.05).

CONCLUSION

Endoscopic stenting should be preferred over surgery to eliminate colonic obstruction in patients with acute malignant ileus.

Outcomes of stent insertion and mortality in obstructive stage IV colorectal cancer patients through 10 year duration

BACKGROUND

Colorectal stents are frequently used in patients with stage IV colorectal cancer with obstruction. However, there are only few studies on changes in outcomes of these patients and on the effect of stents on outcome over a long period of time with ongoing changes in therapeutic strategy, including chemotherapy.

METHODS

We retrospectively evaluated 353 patients with bowel obstruction in stage IV colorectal cancer who underwent colonic stenting between years 2005 and 2014. The study population was divided into three groups based on time periods: 2005-2008, 2009-2011, and 2012-2014.

RESULTS

The frequency of colorectal stent insertion procedure increased over the time periods (13.8%, 18.3%, and 20.8%, respectively). There were no changes in success rate and total complication rate. However, the early complication rate in the 3rd period was significantly lower than in the other periods (15.4% vs. 17.1% vs. 7.2%; P = 0.039). In the multivariate analysis, carcinomatosis (hazard ratio, 1.478; 95% confidence interval, 1.016-2.149; P = 0.041) and covered or partial-covered stent (hazard ratio, 1.733; 95% confidence interval, 1.144-2.624; P = 0.009; hazard ratio, 1.988; 95% confidence interval, 1.132-3.493; P = 0.017, respectively) were associated with increased complication rate. Stent-related perforation was an independent risk factor related with increased mortality. Although survival duration increased over time (P = 0.042), the mortality rate was unchanged across the three time periods.

CONCLUSIONS

Over 10 years, the targeted agent use and survival duration increased, and early complication rate was decreased, without change in late complication rate or mortality rate during the three time periods in patients with obstructive stage IV colorectal cancer and stent insertion.

Vorinostat-eluting poly(DL-lactide-co-glycolide) nanofiber-coated stent for inhibition of cholangiocarcinoma cells

Purpose

The aim of this study was to fabricate a vorinostat (Zolinza™)-eluting nanofiber membrane-coated gastrointestinal (GI) stent and to study its antitumor activity against cholangiocarcinoma (CCA) cells in vitro and in vivo.

Methods

Vorinostat and poly(DL-lactide-co-glycolide) dissolved in an organic solvent was sprayed onto a GI stent to make a nanofiber-coated stent using an electro-spinning machine. Intact vorinostat and vorinostat released from nanofibers was used to assess anticancer activity in vitro against various CCA cells. The antitumor activity of the vorinostat-eluting nanofiber membrane-coated stent was evaluated using HuCC-T1 bearing mice.

Results

A vorinostat-incorporated polymer nanofiber membrane was formed on the surface of the GI stent. Vorinostat was continuously released from the nanofiber membrane over 10 days, and its release rate was higher in cell culture media than in phosphate-buffered saline. Released vorinostat showed similar anticancer activity against various CCA cells in vitro compared to that of vorinostat. Like vorinostat, vorinostat released from nanofibers induced acetylation of histone H4 and inhibited histone deacetylases 1⋅3⋅4/5/7 expression in vitro and in vivo. Furthermore, vorinostat nanofibers showed a higher tumor growth inhibition rate in HuCC-T1 bearing mice than vorinostat injections.

Conclusion

Vorinostat-eluting nanofiber membranes showed significant antitumor activity against CCA cells in vitro and in vivo. We suggest the vorinostat nanofiber-coated stent may be a promising candidate for CCA treatment.

Using stents in the management of malignant bowel obstruction: the current situation and future progress

The use of self-expanding metal stents (SEMS) has been considered an effective and safe alternative to emergency surgery as bridge to surgery or for palliation in advanced colorectal cancer even though more recent data have raised concerns on both early and long-term outcomes when patients are treated with bridge to surgery indications. Areas covered: A comprehensive literature review of articles on endoscopic management of malignant bowel obstruction was performed. Indication, technique, outcomes, benefits and risks of these treatments in acute malignant colonic obstruction were reviewed. The clinical effectiveness and safety of SEMS in obstructive colorectal cancer, as bridge to surgery or for palliation compared to surgery, is discussed. Expert commentary: SEMS placement, when performed in tertiary level center with appropriate expertise in colorectal stenting, may have several advantages over surgery avoiding the potential for surgical morbidity in a typically frail group of patients even though these advantages are to be carefully balanced over the risk of life-threatening, stent-related complications.

Ischemic or toxic injury: A challenging diagnosis and treatment of drug-induced stenosis of the sigmoid colon

A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagnosis of inflammatory bowel disease with stenotic sigmoid colon. Findings from computed tomography virtual colonoscopy, radiography with meglumine diatrizoate, endoscopic balloon dilatation, metallic stent implantation and later overall colonoscopy, coupled with the newfound knowledge of compound Qingdai pill-taking, led to a subsequent diagnosis of ischemic or toxic bowel disease with sigmoid colon stenosis. The patient was successfully treated by laparoscopic sigmoid colectomy, and postoperative pathological examination revealed ischemic or toxic injury of the sigmoid colon, providing a final diagnosis of drug-induced sigmoid colon stenosis. This case highlights that adequate awareness of drug-induced colon stenosis has a decisive role in avoiding misdiagnosis and mistreatment. The diagnostic and therapeutic experiences learnt from this case suggest that endoscopic balloon expansion and colonic metallic stent implantation as bridge treatments were demonstrated as crucial for the differential diagnosis of benign colonic stenosis. Skillful surgical technique and appropriate perioperative management helped to ensure the safety of our patient in subsequent surgery after long-term use of glucocorticoids.

Management of colon stents based on Bernoulli's principle

BACKGROUND AND AIMS

The colonic self-expanding metal stent (SEMS) has been widely used for "bridge to surgery" and palliative therapy. However, if the spread of SEMS is insufficient, not only can a decompression effect not be obtained but also perforation and obstructive colitis can occur. The mechanism of occurrence of obstructive colitis and perforation was investigated by flow dynamics.

METHODS

Bernoulli's principle was applied, assuming that the cause of inflammation and perforation represented the pressure difference in the proximal lumen and stent. The variables considered were proximal lumen diameter, stent lumen diameter, flow rate into the proximal lumen, and fluid density. To model the right colon, the proximal lumen diameter was set at 50 mm. To model the left-side colon, the proximal lumen diameter was set at 30 mm.

RESULTS

For both the right colon model and the left-side colon model, the difference in pressure between the proximal lumen and the stent was less than 20 mmHg, when the diameter of the stent lumen was 14 mm or more. Both the right colon model and the left-side colon model were 30 mmHg or more at 200 mL s^-1 when the stent lumen was 10 mm or less. Even with an inflow rate of 90-110 mL s^-1, the pressure was 140 mmHg when the stent lumen diameter was 5 mm.

CONCLUSION

In theory, in order to maintain the effectiveness of SEMS, it is necessary to keep the diameter of the stent lumen at 14 mm or more.

Preoperative colonic stents vs emergency surgery for acute left-sided malignant colonic obstruction: Meta-analysis with systematic review of the literature

AIM

To investigate by meta-analytic study and systematic review, advantages of colonic stent placement in comparison with emergency surgery.

METHODS

We conducted an extensive literature search by PubMed, Google Scholar, Embase and the Cochrane Libraries. We searched for all the papers in English published till February 2016, by applying combinations of the following terms: Obstructive colon cancer, colon cancer in emergency, colorectal stenting, emergency surgery for colorectal cancer, guidelines for obstructive colorectal cancer, stenting vs emergency surgery in the treatment of obstructive colorectal cancer, self-expanding metallic stents, stenting as bridge to surgery. The study was designed following the Prisma Statement. By our search, we identified 452 studies, and 57 potentially relevant studies in full-text were reviewed by 2 investigators; ultimately, 9 randomized controlled trials were considered for meta-analysis and all the others were considered for systematic review.

RESULTS

In the meta-analysis, by comparing colonic stenting (CS) as bridge to surgery and emergency surgery, the pooled analysis showed no significant difference between the two techniques in terms of mortality [odds ratio (OR) = 0.91], morbidity (OR = 2.38) or permanent stoma rate (OR = 1.67); primary anastomosis was more frequent in the stent group (OR = 0.45; P = 0.004) and stoma creation was more frequent in the emergency surgery group (OR = 2.36; P = 0.002). No statistical difference was found in disease-free survival and overall survival. The pooled analysis showed a significant difference between the colonic stent and emergency surgery groups (OR = 0.37), with a significantly higher 1-year recurrence rate in the stent group (P = 0.007).

CONCLUSION

CS improves primary anastomosis rate with significantly high 1-year follow-up recurrence and no statistical difference in terms of disease-free survival and overall survival.

Diagnosis and treatment of ischemic colitis

Ischemic colitis (IC) is a common reason of acute lower gastrointestinal bleeding, and it is frequently seen in elderly people. In recent years, both the incidence and prevalence of IC have been rising. Most episodes of IC are transient and self-limited and only a minority of cases are severe. IC often has missed and delayed diagnosis. This review mainly focuses on the progress in the understanding of the diagnosis and therapy of IC.

Technical and Clinical Outcomes Following Colonic Stenting: A Seven-Year Analysis of 268 Procedures

AIMS

To assess the factors contributing to the technical and clinical success of colorectal stenting for large bowel obstruction.

METHODOLOGY

268 cases of colonic stenting for large bowel obstruction were performed in 249 patients of mean age of 72 years (28-98) between 2006 and 2013. The majority of strictures were due to malignant disease, 244/268 (91 %). Diverticular strictures accounted for 24/268 (9 %).

RESULTS

Overall technical success rate was 81 % (217/268), with a clinical success rate of 65 % (174/268). Duration of symptoms ranged from 0 to 180 days (mean 8 days). Technical success rate was seen to decrease with increasing symptom duration. For symptom duration of less than 1 week, technical success was 85.4 % (181/212) versus 69.6 % (39/56) for those with symptoms of greater than a week (p < 0.05). Clinical success rates fell from 71.3 % (107/150) to 59.3 % (70/118) (p < 0.05) when attempting to stent lesions of greater than 5 cm. There was also a significant reduction in clinical success when stenting lesions on a bend rather than a straight segment of colon 75.7 % (109/144) versus 59.7 % (74/124) (p < 0.05). A total of 20 (7.46 %) perforations were identified during the study. Stent migration occurred in 6.6 % of cases. In-stent stenosis occurred in 3.3 %. The overall 30-day all cause mortality rate was 9 %.

CONCLUSION

Lesion size, location and duration of obstructive symptoms are statistically significant determinants of patient outcome. These factors could be used to advise patient selection for colonic stenting or direct progression to surgical intervention.