Clinical outcome of self-expandable metal stent placement in the management of malignant proximal colon obstruction

Safety and Effectiveness of Colonic Stenting for Ileocecal Valve Obstruction and Usefulness of Two-Step Strategy: Single-Center Retrospective Study

Background: Endoscopic self-expandable metallic stent (SEMS) placement is a widely accepted treatment for malignant left-sided colorectal obstruction (LSO) because of its lower invasiveness and quicker symptomatic relief compared to surgery. However, SEMS placement for ileocecal valve obstruction (ICVO) has not been established due to its technical difficulties. Methods: This single-center retrospective study compared the clinical outcomes of patients who underwent SEMS placement for ICVO (ICVO group, n = 13) and LSO (LSO group, n = 146). Particularly in cases with severe small-intestine dilation, we applied a "Two-Step Strategy", which involved long intestinal tube insertion followed by SEMS placement to ensure safety and overcome technical challenges. Results: Patients in the ICVO group were significantly more likely to undergo SEMS placement with the Two-Step Strategy compared to those in the LSO group (76.9% vs. 6.9%, p < 0.001). Both groups achieved similarly high technical and clinical success rates (100% vs. 98.6%, p = 1.000; 92.3% vs. 88.4%, p = 1.000), and the incidence of adverse events also showed no significant difference between the groups (7.7% vs. 13.0%; p = 1.000). Furthermore, the median time to recurrent colorectal obstruction and survival time after SEMS placement did not differ between patients with palliative stenting for ICVO and LSO (not reached vs. 430 days, p = 0.586; 119 days vs. 200 days, p = 0.303). Conclusions: SEMS placement for malignant ICVO is as safe and effective as it is for malignant LSO, and the Two-Step Strategy might be useful in ICVO cases.

Colonic stents: who, where, when

Large bowel obstruction can be caused by advanced colonic cancer, extracolonic obstruction or benign strictures. The technical success rate of colonic stents for the treatment of colorectal obstruction is about 87% with complications or technical failure at about 14%. Mortality associated with the procedure is <4% and perforation is 4.5%. This article will discuss who would benefit from colonic stents including bridge to surgery, palliation, benign strictures and who should be performing this procedure. The insertion of stents in the colon has been primarily studied in the left colon, although proximal obstruction will also be discussed. The timing of stent insertion, in relation to symptoms and chemotherapy, will be discussed.

Impact of self-expanding metal stents on long-term survival outcomes as a bridge to surgery in patients with colon cancer obstruction: Current state and future prospects

Since self-expanding metal stents (SEMS) were first introduced in acute colon cancer obstruction, the increased rate of primary anastomosis and improved quality of life following SEMS placement have been clearly shown. However, it was demonstrated that SEMS are associated with higher recurrence rates. Although several trials have shown that overall and disease-free survival in patients following SEMS placement is similar with patients undergoing emergency surgery, obstruction and a high incidence of recurrence imposed many concerns. The optimal time interval from SEMS to surgery is still a matter of debate. Some studies have recommended a time interval of ~2 weeks between SEMS insertion and elective surgery. A prolonged interval of time from SEMS insertion to elective surgery and the administration of neoadjuvant chemotherapy (NAC) has been proposed. SEMS-NAC might have advantages for improving the surgical and long-term survival outcomes of patients with acute colon cancer obstruction, which is an optional approach in the management of acute colon cancer obstruction.

Colon stenting as a bridge to surgery in obstructive colorectal cancer management

Colonic stent placement is a commonly used bridging strategy for surgery in patients with obstructive colorectal cancer. The procedure involves the placement of a self-expandable metallic stent (SEMS) across the obstructive lesion to restore intestinal patency and alleviate the symptoms of obstruction. By allowing patients to receive surgery in a planned and staged manner with time for preoperative optimization and bowel preparation, stent placement may reduce the need for emergency surgery, which is associated with higher complication rates and poorer outcomes. This review focuses on the role of colon stenting as a bridge to surgery in the management of obstructive colorectal cancer. SEMS as a bridge to surgery for left-sided colon cancer has been demonstrated to be particularly useful; however, further research is needed for its application in cases of right-sided colon cancer. Colon stent placement also has limitations and potential complications including stent migration, re-obstruction, and perforation. However, the timing of curative surgery after SEMS placement remains inconclusive. Considering the literature to date, performing surgery at an interval of approximately 2 weeks is considered appropriate. Therefore, colonic stent placement may be an effective strategy as a bridge to surgery in patients with obstructive colorectal cancer.

Efficacy and Safety Analysis of Emergency Endoscopic Self-Expanding Metal Stent Placement Without Fluoroscopic Assistance for Right-Sided Colonic Cancer Obstruction

BACKGROUND

Traditionally, surgical treatment is recommended for right-sided colonic cancer obstruction (RCCO); however, the literature comparing surgical or non-surgical procedures is lacking.

METHODS

Patients included in this study were divided into two groups: one group received elective surgery after self-expanding metal stent (SEMS) placement, i.e., the bridge to surgery (BTS) group, and one group received emergency surgery (ES).

RESULTS

Thirty-five patients were included in the BTS group and 60 patients underwent ES. The technical and clinical success rates for SEMS placement were 100% and 88.6%, respectively, while the short-term complication rates were 51.4% and 33.3% for the BTS and ES groups, respectively (p = 0.082). Overall, 2.9% and 3.3% of postoperative deaths occurred in the BTS and ES groups (p = 1.000). The 1-year overall survival (OS) rates were 91.4% and 88.3% (p = 0.840), 3-year OS rates were 85.7% and 81.7% (p = 0.860), and 5-year OS rates were 82.9% and 76.7% (p = 0.620) in the BTS and ES groups, respectively. No tumor recurrence was found in the BTS group but seven recurrences were found in the ES group (11.7%) [p = 0.091]. Laparoscopic surgery was chosen by 42.9% of patients in the BTS group and 26.7% of patients in the ES group (p = 0.104); however, the length of hospital stay (p = 0.001) was longer in the BTS group.

CONCLUSIONS

In the two groups, no differences were found in terms of postoperative complications and mortality as well as OS. The BTS group preferred to perform laparoscopic surgery and the technical success rate of stenting was high, therefore SEMS for RCCO was considered safe and feasible.

Outcomes according to treatment modalities as a bridge to curative surgery for malignant obstruction of the proximal colon: stent versus stoma

BACKGROUND/AIMS

The optimal treatment for acute malignant obstruction of the proximal colon (MOPC, proximal to the splenic flexure) remains challenging. Emergency resection, the traditional modality for MOPC, has shown significantly high mortality and morbidity rates, according to recent studies. This study aimed to investigate the clinical outcomes of stent vs stoma as a bridge to curative surgery for MOPC.

METHODS

This retrospective cohort study included 72 patients who underwent endoscopic placement of a self-expanding metallic stent (SEMS) or loop ileostomy for MOPC at six referral centers between January 2011 and July 2021. Clinical and pathological characteristics, procedure-related complications, and long-term mortality rates after curative surgery were analyzed.

RESULTS

During a mean follow-up period of 32 months, 30 patients (41.7%) underwent ileostomy preferentially for more proximal cancer, complete obstruction, and advanced tumor stage compared to the SEMS group. No difference was found in procedure-related complications, but five deaths were observed after ileostomy. Survival analysis for 5-year mortality after curative surgery showed no significant difference between the bridge modalities (log-rank p = 0.253).

CONCLUSION

In this study, SEMS as a bridge to surgery showed relatively safe results in terms of post-procedural mortality. However, these results should be considered when performing ileostomy in patients with more advanced malignant obstruction.

Comparison of Short-term Outcomes of a Self-expandable Metallic Stent as a Bridge to Laparoscopic Surgery between Right- and Left-sided Obstructive Colorectal Cancers: A Retrospective Observational Study

OBJECTIVES

Few studies have compared the tumor-site-based postoperative short-term outcomes of a bridge to surgery using self-expandable metallic stents. This study compared the perioperative outcomes following stent placement between right- and left-sided obstructive colorectal cancers, focusing on patients undergoing laparoscopic surgery.

METHODS

This study included 127 patients with stage I-IV obstructive colorectal cancer (right-sided, n = 25 [19.7%]; left-sided, n = 102 [80.3%]) who underwent laparoscopic-assisted surgery following stent placement between May 2012 and September 2021. We compared the postoperative complication rates and the success rates of stent placement.

RESULTS

The clinical success rate was not significantly different (92% vs. 97.1%, P = 0.254). The rates of all-grade complications (36% vs. 16.7%, P = 0.05) and postoperative ileus or small-bowel obstruction (20% vs. 2%, P = 0.003) were significantly higher in the right-sided group. The rates of the Clavien-Dindo classification ≥ III complications (8% vs. 6.9%, P = 1) and the median durations of postoperative hospital stay (8 days vs. 8 days, P = 1) were not significantly different. On multivariate analysis, right-sided colon cancer was an independent risk factor for postoperative ileus or small-bowel obstruction (odds ratio [OR]: 16.5, 95% confidence interval [CI]: 2.42-112, P = 0.004) but not for all grades of complications (OR: 2.63, 95% CI: 0.976-7.09, P = 0.056).

CONCLUSIONS

Although the rates of clinical success, postoperative Clavien-Dindo classification ≥ III severe complications, and postoperative hospital stay were comparable, the bridge to surgery following stent placement for right-sided obstructive colon cancer raises concerns about ileus or small-bowel obstruction.

Clinical outcomes of palliative self-expandable metal stent placement in right- and left-sided malignant colon obstruction: A Honam Association for the Study of Intestinal Disease (HASID) multicenter study

Self-expandable metal stent (SEMS) placement is commonly used for palliation of left-sided malignant colorectal obstruction (MCO). However, right-sided MCO is usually treated surgically. Recent studies that compared palliative SEMS insertion and emergency surgery in right-sided MCOs have reported conflicting results. This study aimed to compare the effectiveness of palliative SEMS placement in left-sided MCOs and right-sided MCOs and to investigate the predictive factors for clinical success and risk factors for complications. Data from 469 patients who underwent palliative SEMS placement for MCO at 6 hospitals in the Honam province of South Korea between 2009 and 2018 were reviewed. Among them, 69 patients with right-sided MCO and 400 patients with left-sided MCO who underwent SEMS placement for palliative purposes were enrolled. Clinical success, overall survival, complications, and predictive factors for clinical success and risk factors for complications were included as the main outcome measures. The clinical success rates were 97.1% (65/67) in right-sided MCO patients and 88.2% (353/400) in left-sided MCO patients. Complications including stent migration, tumor ingrowth, outgrowth, perforation, bacteremia/fever, and bleeding occurred in 10.1% (7/69) of right-sided MCO patients and 19.9% (79/400) of left-sided MCO patients. The mean overall survival of right-sided MCO was 28.02 months and 18.23 months for left-sided MCO. In multivariate logistic regression analysis, T3 stage tumors and the use of uncovered stents were significant factors for the clinical success of SEMS. The use of covered stents and performance status score of 0 to 2 were independent significant risk factors for complications. Palliative SEMS placement in right-sided MCO showed better clinical success rates than left-sided MCO. The use of uncovered stents is recommended for higher clinical success rates and lower complication rates.

Colonic stent as a bridge to surgery versus emergency resection for right-sided malignant large bowel obstruction: a meta-analysis

BACKGROUND

Preoperative colonic stenting for malignant large bowel obstruction (MLBO), also called bridge to surgery (BTS), is considered a great substitute treatment for emergency resection (ER) in the left-sided colon. However, its efficacy in the right-sided colon remains controversial. This systematic review and meta-analysis aimed to compare the postoperative short-term outcomes between BTS and ER for right-sided MLBO.

METHODS

A comprehensive electronic literature search throughout December 2020 was performed to identify studies comparing short-term outcomes between BTS and ER for right-side MLBO. The main outcome measures were postoperative complications and mortality rates. A meta-analysis was performed using a fixed-effect or a random-effect method to calculate odds ratios (ORs) with 95% confidence intervals (95% CIs).

RESULTS

Seven studies were included in this meta-analysis, comprising 5136 patients, of whom 1662 (32.4%) underwent BTS and 3474 (67.6%) underwent ER. This meta-analysis demonstrated that BTS resulted in reductions in postoperative complications (OR = 0.78; 95% CI: 0.66-0.92) and mortality (OR = 0.51; 95% CI: 0.28-0.92) than ER.

CONCLUSION

The results of this meta-analysis indicate that BTS for right-sided MLBO confers preferable short-term outcomes as well as for left-sided. This suggests that BTS results in a reduction of postoperative complications and mortality for right-sided MLBO than ER.

A Systematic Review Comparing Emergency Resection and Staged Treatment for Curable Obstructing Right-Sided Colon Cancer

BACKGROUND

Treatment for obstructing colon cancer (OCC) is controversial because the outcome of acute resection is less favorable than for patients without obstruction. Few studies have investigated curable right-sided OCC, and patients with OCC usually undergo acute resection. This study aimed to better understand the outcome and best management of potentially curable right-sided OCC.

METHODS

A systematic review of studies was performed with a focus on differences in mortality and morbidity between emergency resection and staged treatment for patients with potentially curable right-sided OCC. In March 2019, the study searched Embase, Medline, Web of Science, Cochrane, and Google scholar databases according to PRISMA guidelines using search terms related to "colon tumour," "stenosis or obstruction and surgery," and "decompression or stents." All English-language studies reporting emergency or staged treatment for potentially curable right-sided OCC were included in the review. Emergency resection and staged resection were compared for mortality, morbidity, complications, and survival.

RESULTS

Nine studies were found to be eligible and comprised 600 patients treated with curative intent for their right-sided OCC by emergency resection or staged resection. The mean overall complication rate was 42% (range 19-54%) after emergency resection, and 30% (range 7-44%) after staged treatment. The average mortality rate was 7.2% (range 0-14.5%) after emergency resection and 1.2% (range 0-6.3%) after staged treatment. The 5-year disease-free and overall survival rates were comparable for the two treatments.

CONCLUSIONS

The patients who received staged treatment for right-sided OCC had lower mortality rates, fewer complications, and fewer anastomotic leaks and stoma creations than the patients who had emergency resection.

Stent as a bridge to surgery versus urgent surgery for malignant right colonic obstruction: A multicenter retrospective study

BACKGROUND

The impact of self-expandable metal stent (SEMS) for malignant right colonic obstruction remains undefined. The aim of this study was to compare short-term postoperative and long-term oncologic outcomes of colonic stenting as a bridge to surgery (SBTS) and urgent colectomy for patients with malignant right-sided obstruction.

METHODS

A total of 98 consecutive patients who underwent SEMS placement during the period 2004-2015 from three hospitals were included. For comparative analyses, patients were matched (1:2) with 196 patients treated with emergency colectomy from our prospective database.

RESULTS

The two groups were comparable in terms of demographics and tumor characteristics. The proportion of patients who underwent laparoscopic colectomy was higher in SBTS group than urgent colectomy group (75.5% vs. 37.2%; p < 0.001). Patients treated with SBTS were less likely to have a temporary stoma constructed (3.1% vs. 10.7%; p = 0.024). SBTS was associated with significantly less median estimated blood loss (90 vs. 100 ml; p = 0.029), shorter length of hospital stay (11 vs. 12 days; p < 0.001), lower overall postoperative complication rate (18.4% vs. 31.3%; p = 0.018), and wound-related complication rate (5.1% vs. 14.3%; p = 0.019) compared with urgent surgery. Reoperation rate, 30-day mortality, and lymph nodes harvested were not significantly different between two groups. Disease-free survival rate and overall survival rate were similar between the two groups.

CONCLUSIONS

SEMS insertion is safe and feasible for treating malignant right-sided obstruction. SBTS is associated with better short-term outcomes and equivalent long-term oncologic results compared with urgent colectomy.

Stent as a bridge to surgery or immediate colectomy for malignant right colonic obstruction: propensity-scored, national database study

Background

The aim of this study was to compare perioperative outcomes of urgent colectomy and placement of a self-expanding metallic stent followed by colectomy for patients with malignant right colonic obstruction. Right-sided malignant obstruction is less common than left-sided. Stenting for malignant left colonic obstruction has been reported to reduce postoperative complications. However, the impact of stenting for malignant right colonic obstruction remains undefined.

Methods

The study included patients with right-sided malignant obstruction or stenosis undergoing colectomy between April 2012 and March 2017 identified from a nationwide database. Propensity score matching analysis was used to compare mortality and morbidity rates, proportion receiving a stoma and postoperative stay between urgent colectomy and stent groups.

Results

From 9572 patients, 1500 pairs were generated by propensity score matching. There was no significant difference in in-hospital mortality between the urgent colostomy and stent groups (1·6 versus 0·9 per cent respectively; P = 0·069). Complications were more common after urgent colectomy than stenting (22·1 versus 19·1 per cent; P = 0·042). Surgical-site infection was more likely with urgent colectomy (7·1 versus 4·4 per cent; P = 0·001). There was no significant difference between the two groups in anastomotic leakage (3·8 versus 2·6 per cent; P = 0·062). The proportion of patients needing a stoma was higher with urgent colectomy than primary treatment with stents (5·1 versus 1·7 per cent; P &lt; 0·001). Postoperative stay was longer after urgent colectomy (15 versus 13 days; P &lt; 0·001).

Conclusion

Stenting followed by colectomy in patients with malignant right colonic obstruction may provide more favourable perioperative outcomes than urgent colectomy.

Endoscopic Management of Malignant Colonic Obstruction

Advanced colorectal cancer can cause acute colonic obstruction, which is a life-threatening condition that requires emergency bowel decompression. Malignant colonic obstruction has traditionally been treated using emergency surgery, including primary resection or stoma formation. However, relatively high rates of complications, such as anastomosis site leakage, have been considered as major concerns for emergency surgery. Endoscopic management of malignant colonic obstruction using a self-expandable metal stent (SEMS) was introduced 20 years ago and it has been used as a first-line palliative treatment. However, endoscopic treatment of malignant colonic obstruction using SEMSs as a bridge to surgery remains controversial owing to short-term complications and longterm oncological outcomes. In this review, the current status of and recommendations for endoscopic management using SEMSs for malignant colonic obstruction will be discussed.

恶性肠梗阻的治疗现状与进展

恶性肠梗阻(malignant bowel obstruction, MBO)是晚期肿瘤常见并发症之一, 严重影响患者的生活质量. 恶性肿瘤本身的复杂性导致肠梗阻治疗的复杂性、难治性. 近年来, 随着腹腔镜、内镜技术及介入技术的发展以及对姑息手术适应证的把握, 肠梗阻患者的生存质量及治疗率得以提高, 但尚存在一定争议, 且在药物治疗方面暂无显著进展. 另外, 中医药在该领域亦有较多研究, 显示出一定的效果, 但尚缺乏前瞻性的随机对照研究. 临床处理要充分考虑治疗可能带来的益处及风险, 慎重选择个性化的治疗方案. 本文对国内外近年来MBO的中西医诊疗进展进行系统综述, 以期对临床诊疗具有一定的指导意义.

Long-term outcomes of palliative colonic stenting versus emergency surgery for acute proximal malignant colonic obstruction: a multicenter trial

Background and study aims Long-term data are limited regarding clinical outcomes of self-expanding metal stents as an alternative for surgery in the treatment of acute proximal MBO. The aim of this study was to compare the long-term outcomes of stenting to surgery for palliation in patients with incurable obstructive CRC for lesions proximal to the splenic flexure. Patients and methods Retrospective multicenter cohort study of obstructing proximal CRC patients with who underwent insertion of a SEMS (n = 69) or surgery (n = 36) from 1999 to 2014. The primary endpoint was relief of obstruction. Secondary endpoints included technical success, duration of hospital stay, early and late adverse events (AEs) and survival. Results Technical success was achieved in 62/69 (89.8 %) patients in the SEMS group and in 36 /36 (100 %) patients who underwent surgery (P = 0.09). In the SEMS group, 10 patients underwent stenting as a bridge to surgery and 59 underwent stent placement for palliation. Clinical relief was achieved in 78 % of patients with stenting and in 100 % of patients who underwent surgery (P < 0.001). Patients with SEMS had significantly less acute AEs compared to the surgery group (7.2 % vs. 30.5 %, P = 0.003). Hospital mortality for the SEMS group was 0 % compared to 5.6 % in the surgery group (P = 0.11). Patients in the SEMS group had a significantly shorter median hospital stay (4 days) as compared to the surgery group (8 days) (P < 0.01). Maintenance of decompression without the recurrence of bowel obstruction until death or last follow-up was lower in the SEMS group (73.9 %) than the surgery group (97.3 %; P = 0.003). SEMS placement was associated with higher long-term complication rates compared to surgery (21 % and 11 % P = 0.27). Late SEMS AEs included occlusion (10 %), migration (5 %), and colonic ulcer (6 %). At 120 weeks, survival in the SEMS group was 5.6 % vs. 0 % in the surgery group (P = 0.8). Conclusions Technical and clinical success associated with proximal colonic obstruction are higher with surgery when compared to SEMS, but surgery is associated with longer hospital stays and more early AEs. SEMS should be considered the initial mode of therapy in patients with acute proximal MBO and surgery should be reserved for SEMS failure, as surgery involves a high morbidity and mortality.

Radiologic Placement of Uncovered Stents for the Treatment of Malignant Colonic Obstruction Proximal to the Descending Colon

PURPOSE

To evaluate the safety, feasibility, and patency rates of radiologic placement of uncovered stents for the treatment of malignant colonic obstruction proximal to the descending colon.

MATERIALS AND METHODS

This was a retrospective, single-center study. From May 2003 to March 2015, 53 image-guided placements of uncovered stents (44 initial placements, 9 secondary placements) were attempted in 44 patients (male:female = 23:21; mean age, 71.8 years). The technical and clinical success, complication rates, and patency rates of the stents were also evaluated. Technical success was defined as the successful deployment of the stent under fluoroscopic guidance alone and clinical success was defined as the relief of obstructive symptoms or signs within 48 h of stent deployment.

RESULTS

In total, 12 (27.3 %) patients underwent preoperative decompression, while 32 (72.7 %) underwent decompression with palliative intent. The technical success rate was 93.2 % (41/44) for initial placement and 88.9 % (8/9) for secondary placement. Secondary stent placement in the palliative group was required in nine patients after successful initial stent placement due to stent obstruction from tumor ingrowth (n = 7) and stent migration (n = 2). The symptoms of obstruction were relieved in all successful cases (100 %). In the palliative group, the patency rates were 94.4 % at 1 month, 84.0 % at 3 months, 64.8 % at 6 months, and 48.6 % at 12 months.

CONCLUSIONS

The radiologic placement of uncovered stents for the treatment of malignant obstruction proximal to the descending colon is feasible and safe, and provides acceptable clinical results.

A Population-Based Analysis of Three Treatment Modalities for Malignant Obstruction of the Proximal Colon: Acute Resection Versus Stent or Stoma as a Bridge to Surgery

BACKGROUND

Malignant obstruction of the proximal colon (MOPC) traditionally has been treated with acute resection. However, morbidity and mortality rates following these emergency surgeries are high. Initial bowel decompression by stent placement or stoma construction has been used for distal obstructions as an alternative approach. This study evaluated whether these alternative treatment strategies could be beneficial for patients with a MOPC as well.

METHODS

All patients undergoing a colonic resection for a MOPC between January 2009 and December 2013 and who were registered in the Dutch Surgical Colorectal Audit were analyzed.

RESULTS

From the 49,013 patients registered in the DSCA, 1860 (3.8 %) were selected for further analysis. Acute resection was performed in 1774 patients (95.4 %), 44 patients (2.4 %) were treated with initial decompression using stent placement and resection, and 42 patients (2.3 %) with stoma construction followed by resection. Thirty-day mortality was 8.8, 2.4, and 2.4 %, respectively. Mortality was significantly lower after a bridging strategy (stent or stoma) compared with acute resection (p = 0.04). Complications following the resection occurred in 39.6% in the acute resection group and in 27.3 and 31.7% in the stent and stoma group, respectively (p = 0.167).

CONCLUSIONS

Acute resection was performed in the vast majority of patients with obstructive proximal colon cancer and resulted in a 40 % morbidity and 9 % mortality rate. A bridging strategy may be a valid alternative in some of these patients, because a significantly lower postoperative mortality rate was seen in a subgroup of patients initially treated with a stent or stoma.

Evidence-based Clinical Management of Acute Malignant Colorectal Obstruction

Acute malignant colorectal obstruction (AMCO) is an emergency associated with colorectal cancer (CRC). Emergency surgery is standard therapy for AMCO, and 1-stage surgery without colostomy is preferable, but it is occasionally difficult in the emergency setting. A self-expandable metallic stent (SEMS) enables noninvasive colonic decompression and subsequent 1-stage surgery, which has been widely applied for CRC with AMCO. However, recent accumulation of high-quality evidence has highlighted some problems and the limited efficacy of SEMS for AMCO. In palliative settings, SEMS placement reduces hospital stay and short-term complication rates, whereas it increases the frequency of long-term complications, such as delayed perforation. SEMS placement does not seem compatible with recent standard chemotherapy including bevacizumab. As a bridge to surgery, while SEMS placement provides a lower clinical success rate than emergency surgery, it can facilitate primary anastomosis without stoma. However, evidence regarding long-term survival outcomes with SEMS in both palliative and bridge to surgery settings is lacking. The efficacy of transanal colorectal tube placement, another endoscopic treatment, has been reported, but its clinical evidence level is low due to the limited number of studies. This review article comprehensively summarizes the current knowledge about surgical and endoscopic management of CRC with AMCO.

Self-Expanding Metallic Stents for the Management of Emergency Malignant Large Bowel Obstruction: a Systematic Review

OBJECTIVES

This paper evaluates the safety and effectiveness of self-expanding metallic stents (SEMS) for the management of emergency malignant colorectal obstruction in patients otherwise requiring multi-stage surgery. No systematic review has been conducted comparing SEMS to only multi-stage surgery.

METHODS

Bibliographic databases, including Cochrane, PubMed, EMBASE, and CINAHL, were searched in September 2011 and repeated in November 2013. A pre-determined protocol outlined the study inclusion and appraisal.

RESULTS

Forty articles were included, seven compared SEMS to multi-stage surgery. Included studies were of low to moderate quality. Bowel perforation was the most severe stent-related complication, while tumor- and stent-related events occurred most frequently. No significant differences in rates of obstruction relief were reported between treatments, and results regarding relative quality of life were inconclusive. SEMS recipients progressed to elective surgery sooner and required shorter post-procedural hospital stays, but commonly required re-intervention. SEMS provided enduring palliative relief of obstruction, with comparable survival longevity between treatments. Conclusion: SEMS placement is a viable alternative to multi-stage surgery, providing patients with benefits as a bridge-to-surgery and relief of obstruction in a palliative context, with minimal differences in clinical success and safety compared to multi-stage surgery.

Comparison of Long-Term Outcomes Between Emergency Surgery and Bridge to Surgery for Malignant Obstruction in Right-Sided Colon Cancer: A Multicenter Retrospective Study

BACKGROUND

Malignant obstruction in right-sided colon (MORC) has traditionally been treated by emergency resection with primary anastomosis. The aim of this study was to evaluate short-term postoperative and long-term oncologic outcomes according to the surgical approach adopted for MORC.

METHODS

A total of 1785 patients who underwent curative surgery for stage II or III colon cancer in seven hospitals were reviewed retrospectively. Seventy-four of 1785 patients had MORC. We compared the postoperative outcome and long-term oncologic outcome between the emergency surgery (ES) group (49 patients) and the bridge to surgery (BS) group (25 patients) for 74 patients with MORC.

RESULTS

There were no differences in the length of the distal and proximal resection margin (p = 0.820 and p = 0.620) or the number of metastatic lymph nodes (p = 0.221). There were no differences in flatus passage (p = 0.242), start of diet (p = 0.336), hospital stay (p = 0.444), or postoperative morbidity (p = 0.762). The 5-year overall survival rates were 73.2 % in the ES group and 90.7 % in the BS group (p = 0.172). Moreover, the 5-year disease-free survival rates were 71.9 % in the ES group and 76.2 % in the BS group (p = 0.929).

CONCLUSIONS

On the basis of the above results, the postoperative course of the ES group was similar to that of the BS group. In addition, the long-term oncologic outcome of the BS group was similar or slightly better than that of the ES group. BS after colonic stent may be an alternative option for MORC.

Stents for colorectal obstruction: Past, present, and future

Since the development of uncovered self-expanding metal stents (SEMS) in the 1990s, endoscopic stents have evolved dramatically. Application of new materials and new designs has expanded the indications for enteral SEMS. At present, enteral stents are considered the first-line modality for palliative care, and numerous types of enteral stents are under development for extended clinical usage, beyond a merely palliative purpose. Herein, we will discuss the current status and the future development of lower enteral stents.

Emergency resection versus bridge to surgery with stenting in patients with acute right-sided colonic obstruction: a systematic review focusing on mortality and morbidity rates

PURPOSE

No consensus exists on the optimal treatment of acute malignant right-sided colonic obstruction (RSCO). This systematic review aims to compare procedure-related mortality and morbidity rates between primary resection and stent placement as a bridge to surgery followed by elective resection for patients with acute RSCO.

METHODS

PubMed, Embase and Cochrane library were searched for all relevant literature. Primary endpoints were procedure-related mortality and morbidity. Methodological quality of the included studies was assessed using the MINORS criteria.

RESULTS

Fourteen cohort studies were eligible for analysis. A total of 2873 patients were included in the acute resection group and 155 patients in the stent group. Mean mortality rate for patients who underwent acute resection with primary anastomosis was 10.8% (8.1-18.5%). Overall mortality for patients initially treated with a colonic stent followed with elective resection was 0%. Major morbidity was 23.9% (9.3-35.6%) and 0.8% (0-4.8%), respectively. Both mortality and major morbidity were significantly different. In addition, stent placement shows lower rates of anastomotic leakages (0 vs 9.1%) and fewer permanent ileostomies (0 vs 1.0%).

CONCLUSION

Primary resection for patients with acute RSCO seems to be associated with higher mortality and major morbidity rates than stent placement and elective resection. In addition, stent placement resulted in fewer anastomotic leakages and permanent ileostomies. However, as no high-level studies are available on the optimal treatment of RSCO and proximal stenting is considered technically challenging, future comparative studies are warranted for the development of an evidence-based clinical decision guideline.

Novel stenting method for malignant right colonic stenosis using ultra-thin endoscopy: Report of four cases

Placement of a self-expandable metallic stent (SEMS) is recognized as a safe and effective procedure for patients with malignant severe colonic stenosis. However, reports of this stent for right-sided colonic stenosis are limited, possibly as a result of technical difficulties. We report a new method for delivering SEMS to the site of right-sided colonic stenosis in four patients with malignant right-sided colonic stenosis. Technical success was obtained with sequential use of a double-balloon endoscope and ultrathin endoscope, while we also injected non-ionic contrast agent into the submucosal layer as a marker for stenting under fluoroscopy. There were no adverse events noted during the procedure and clinical improvement was seen in all four cases. In conclusion, SEMS placement for right-sided malignant colonic stenosis with our newly developed method appears to be safe and effective, and can be used for decompression of the right colon.

Retrospective evaluation of endoscopic stenting of combined malignant common bile duct and gastric outlet-duodenum obstructions

Malignant dual obstruction in the common bile duct and gastric outlet-duodenum can cause difficulties in palliative treatment. The purpose of this study was to summarize our successful experience with the endoscopic stenting procedure for the palliative treatment of malignant biliary and gastric outlet-duodenum obstruction. Seventeen patients who underwent dual stenting procedures for the common bile duct and duodenum were retrospectively reviewed. The success rate of placement, palliative effect for biliary and duodenal obstruction, incidence of complication and restricture and stent patency were analyzed. Stent placement achieved a 100% success rate. Total bilirubin decreased from 263.4±62.5 to 157.6±25.1 μmol/l, direct bilirubin decreased from 233.2±66.5 to 130.9±27.7 μmol/l and alkaline phosphatase from 534.2±78.7 to 216.3±23.3 IU/l. The differences between the preoperative and postoperative results were statistically significant (P<0.01). The gastric outlet obstruction score increased significantly from 0.9±1.1 to 2.1±0.7 points (P<0.01). The general nutritional status of the patients was improved. No serious complications occurred in any of the patients, and the survival time of patients following stenting ranged between 70 and 332 days with a mean survival time of 192 days. In conclusion, our methodology for combined biliary and enteral stenting is highly effective for the palliation of malignant biliary and gastric outlet-duodenal obstruction.

Analysis of risk factors associated with complications of colonic stenting for malignant obstruction

Self expanding metalic stent (SEMS) application can cause serious problems up to one third of the patients and some studies reported negative effect of SEMSs on survival in patients with malignancy. The SEMS type especially the rigid one like Wall-stent rather than more flexible type Ultraflex was also reported to have bad impact on the risk of perforation we believe that stent based management protocol for patients with non-perforating left sided obstructing colorectal cancer is a complex method that needs qualified medical and technical team.

Self-expanding metallic stents for palliation and as a bridge to minimally invasive surgery in colorectal obstruction

Self-expanding metallic stents are effective for the palliation of malignant obstruction. This study indicates that stents for bowel obstruction may allow for minimally invasive surgical intervention with a shorter hospital stay, lower stoma rate, and earlier chemotherapy administration.

Background and Objectives:

Acute colorectal obstruction is a potentially life-threatening emergency that requires immediate surgical treatment. Emergency procedures had an associated mortality rate of 10% to 30%. This encouraged development of other options, most notably self-expanding metallic stents. The primary endpoint of this study to is to report our group's experience.

Methods:

We performed a retrospective review of 37 patients who underwent self-expanding metallic stent placement for colorectal obstruction between July 2000 and May 2012. Data collected were age, comorbidities, diagnosis, intent of intervention (palliative vs bridge to surgery), complications, and follow-up.

Results:

The study comprised 21 men (56.76%) and 16 women (43.24%), with a mean age of 67 years. The intent of the procedure was definitive treatment in 22 patients (59.46%) and bridge to surgery in 15 (40.54%). The highest technical success rate was at the rectosigmoid junction (100%). The causes of technical failure were inability of the guidewire to traverse the stricture and bowel perforation related to stenting. The mean follow-up period was 9.67 months. Pain and constipation were the most common postprocedure complications.

Discussion:

The use of a self-expanding metallic stent has been shown to be effective for palliation of malignant obstruction. It is associated with a lower incidence of intensive care unit admission, shorter hospital stay, lower stoma rate, and earlier chemotherapy administration. Laparoscopic or robotic surgery can then be performed in an elective setting on a prepared bowel. Therefore the patient benefits from advantages of the combination of 2 minimally invasive procedures in a nonemergent situation. Further large-scale prospective studies are necessary.

Angular positioning of stent increases bowel perforation after self-expandable metal stent placement for malignant colorectal obstruction

Background/Aims

Some factors like stent wires, balloon dilatation and use of guide wires seems to increase perforation after self-expandable metal stent (SEMS) placement, but few studies mentioned about the relationship between angulation of malignant stricture and perforation. The present study aimed to confirm that more angular positioning of stents increases perforation.

Methods

This study was conducted with retrospectively evaluation at Digestive Disease Center, CHA Bundang Medical Center, CHA University. Between January 2002 and August 2011, SEMS was inserted in 130 patients with malignant colorectal obstruction. We studied the difference in the angle of stenosis between perforation and non-perforation groups using fluorography images.

Results

SEMS insertion was performed in 130 cases of obstruction due to colon cancer. Perforation occurred in eight patients (6.2%) of them. Thirteen cases were excluded from the analysis due to poor fluoroscopic images. Among the eight patients with perforation, the mean stenosis angle was 109.9° compared to 153.1° in the nonperforation group, indicating that the angle was more acute in the perforation group (p=0.016).

Conclusions

This study shows that more angular positioning of stent increases bowel perforation after SEMS placement for malignant colorectal obstruction.

Comparison of treatment outcomes of endoscopic stenting for colonic and extracolonic malignant obstruction

BACKGROUND

Self-expandable metal stents (SEMS) have been used as a bridging or palliative treatment for malignant colorectal obstruction. Colonic obstruction also may arise from advanced extracolonic malignancy, but the clinical outcomes of stent placement for extracolonic malignancy are unclear. This study compared the clinical outcomes of SEMS between patients with colorectal cancer and those with extracolonic malignancy.

METHODS

Patients who underwent endoscopic SEMS placement for a malignant colorectal obstruction were enrolled at Seoul National University Hospital from April 2005 and August 2011. Their medical records were retrospectively reviewed in terms of success rate, complications, and duration of stent patency.

RESULTS

Endoscopic SEMS placements were performed for colorectal cancer in 149 patients and for extracolonic malignancy in 60 patients. The causes of obstruction in extracolonic malignancy were advanced gastric cancer in 39 patients (65%), pancreatic cancer in nine patients (15%), ovarian cancer in three patients (5%) and other causes in nine patients (15%). The clinical success rates were similar between the two groups (92.6 vs 86.7%; p = 0.688), and multivariate analysis showed no significant risk factor for unsuccessful endoscopic SEMS placement. Reobstruction in palliative endoscopic SEMS placement occurred for 16 patients with colorectal cancer (21.9%) and 18 patients with extracolonic malignancy (30%) during a median follow-up period of 90 days (p = 0.288). The rates did not differ significantly between the two groups (4.1 vs 8.3%; p = 0.467). The median duration of stent patency was 193 ± 42 days for the patients with colorectal cancer and 186 ± 31 days for the patients with extracolonic malignancy (p = 0.253). The duration of stent patency was not affected by underlying malignancy, previous surgery, or palliative chemotherapy.

CONCLUSIONS

Endoscopic SEMS placement is highly effective and comparable for palliation of obstruction in extracolonic malignancy and colorectal cancer in terms of clinical success, complications, and duration of patency.

The learning curve for colorectal stent insertion for the treatment of malignant colorectal obstruction

BACKGROUND/AIMS

We aimed to assess the effectiveness of self-expanding metal stent (SEMS) insertion by evaluating the learning curve in relation to the experience of an endoscopist.

METHODS

We retrospectively analyzed the outcomes of 120 SEMS insertion procedures performed by one endoscopist in patients with malignant colorectal obstruction. We compared the technical and clinical success rates, complication rates, and duration of the procedures by quartiles.

RESULTS

The mean age of the patients (76 men and 44 women) was 64.6 years. The overall technical success rate was 95.0% (114/120), and the clinical success rate was 90.0% (108/120). The median procedure duration was 16.2 minutes (range, 3.4 to 96.5 minutes). From the first to the last quartile, the technical success rates were 90.0%, 96.7%, 96.7%, and 96.7% (p=0.263), and the clinical success rates were 90.0%, 90.0%, 96.7%, and 83.3% (p=0.588), respectively. Procedure-related complications were observed in 28 patients (23.3%). The complication rates for SEMS insertion when patients were divided by quartiles were 26.7%, 23.3%, 10.0%, and 33.3% (p=0.184), respectively. Moreover, the number of stents per procedure was 1.13, 1.03, 1.00, and 1.00 (p=0.029), respectively. The median duration of SEMS insertion decreased significantly, 20.9 to 14.8 minutes after the first 30 procedures (p=0.005).

CONCLUSIONS

An experienced endoscopist was able to perform the SEMS insertion procedure easily and effectively after performing 30 SEMS insertions.

Endoskopische Möglichkeiten der Behandlung von Nahtinsuffizienzen im Rektum

<b><i>Hintergrund: </i></b>Anastomoseninsuffizienzen stellen eine gefürchtete Komplikation der kolorektalen Chirurgie dar. Endoskopische Techniken haben sich in der Therapie der Leckagen zunehmend etabliert. In dieser Übersicht möchten wir einen Überblick der wichtigsten endoskopischen Verfahren geben. <b><i>Methode: </i></b>Systematische Recherche der vorhandenen Literatur. <b><i>Ergebnisse: </i></b>Die bedeutendsten endoskopischen Verfahren zur Behandlung der kolorektalen Anastomoseninsuffizienzen stellen die Fibrininjektion, die Vakuumschwammtherapie (Endo-Sponge), spezielle Clip-Systeme (OTSC) sowie die Stentimplantation dar. Der breiten klinischen Anwendung dieser Verfahren steht jedoch eine unzureichende Studienlage gegenüber. <b><i>Schlussfolgerung: </i></b>Die Einschätzung der Wertigkeit der einzelnen endoskopischen Verfahren untereinander und in speziellen therapeutischen Situationen hängt im Wesentlichen von der Erfahrung der Untersucher ab. Es bedarf der Durchführung randomisierter, prospektiver Studien, um diese Erfahrungen zu objektivieren.

Likelihood-based association analysis for nuclear families and unrelated subjects with missing genotype data

Missing data occur in genetic association studies for several reasons including missing family members and uncertain haplotype phase. Maximum likelihood is a commonly used approach to accommodate missing data, but it can be difficult to apply to family-based association studies, because of possible loss of robustness to confounding by population stratification. Here a novel likelihood for nuclear families is proposed, in which distinct sets of association parameters are used to model the parental genotypes and the offspring genotypes. This approach is robust to population structure when the data are complete, and has only minor loss of robustness when there are missing data. It also allows a novel conditioning step that gives valid analysis for multiple offspring in the presence of linkage. Unrelated subjects are included by regarding them as the children of two missing parents. Simulations and theory indicate similar operating characteristics to TRANSMIT, but with no bias with missing data in the presence of linkage. In comparison with FBAT and PCPH, the proposed model is slightly less robust to population structure but has greater power to detect strong effects. In comparison to APL and MITDT, the model is more robust to stratification and can accommodate sibships of any size. The methods are implemented for binary and continuous traits in software, UNPHASED, available from the author.