Self-Expandable Metal Stents for Colorectal Cancer: From Guidelines to Clinical Practice

Manufacturing, Processing, and Characterization of Self-Expanding Metallic Stents: A Comprehensive Review

This paper aims to review the State of the Art in metal self-expanding stents made from nitinol (NiTi), showing shape memory and superelastic behaviors, to identify the challenges and the opportunities for improving patient outcomes. A significant contribution of this paper is its extensive coverage of multidisciplinary aspects, including design, simulation, materials development, manufacturing, bio/hemocompatibility, biomechanics, biomimicry, patency, and testing methodologies. Additionally, the paper offers in-depth insights into the latest practices and emerging trends, with a special emphasis on the transformative potential of additive manufacturing techniques in the development of metal stents. By consolidating existing knowledge and highlighting areas for future innovation, this review provides a valuable roadmap for advancing nitinol stents.

Outcomes After Colonic Self-Expanding Metal Stent Insertion Without Fluoroscopy: A Surgeon-Led 10-Year Experience

INTRODUCTION

Colonic self-expanding metal stents (SEMS) can be used to relieve malignant and benign large bowel obstruction (LBO) as a bridge to surgery (BTS) and for palliation. Guidelines suggest the use of fluoroscopic guidance for deployment. This may be difficult to obtain after hours and in certain centers. We aimed to determine the outcomes of stenting under endoscopic guidance alone.

METHODS

All patients who underwent SEMS insertion in our tertiary referral center between August 2010 and June 2021 were identified from a prospectively maintained database. Patient demographics (age/gender), disease characteristics (benign versus malignant/location/stage), stenting intent (BTS versus palliative), and outcomes (technical success/stoma/time from stenting to resection/death/study end) were analyzed.

RESULTS

Fifty-three (n = 39, 73.6% male) patients underwent SEMS insertion. Indications included colorectal carcinoma (n = 48, 90.6%), diverticular stricture (n = 3), and gynecological malignancy (n = 2). In five (9.4%) patients (four BTS and one palliative), SEMSs deployment was not completed because of the inability to pass the guidewire. All underwent emergency surgery. In the BTS cohort (n = 29, median 70.4 [range 40.3-91.8] years), 10 patients underwent neoadjuvant chemoradiotherapy. The permanent stoma rate was 20.7% (n = 6). There was no 30- or 90-d mortality. In the palliative cohort (n = 24, median age 77.1 [range 54.4-91.9]), 16 (66.7%) were deceased at the study end. The median time from stenting to death was 5.2 (2.3-7.9) months.

CONCLUSIONS

SEMS placed under endoscopic visualization alone, palliatively and as a BTS, had acceptable stoma, morbidity, and mortality rates. These results show that SEMS insertion can be safely performed without fluoroscopy.

Colonic stent vs surgical resection of the primary tumor. Effect on survival from stage-IV obstructive colorectal cancer

BACKGROUND AND OBJECTIVES

the impact of surgical primary tumor resection on survival of obstructive metastatic colorectal cancer remains controversial. The primary goal of this study was to analyze survival in patients with obstructive metastatic colorectal cancer after treatment with either resection surgery or a colonic stent.

MATERIAL AND METHODS

a prospective study was performed of all patients with stage-IV colorectal cancer and obstructive manifestations, diagnosed from 2005 to 2012 and managed with either resection surgery or a colonic stent. Cases with a perforation, abscess, right colon or distal rectal malignancy, multiple colorectal cancer or derivative surgery were excluded.

RESULTS

a total of 95 patients were included, 49 were managed with resection surgery and 46 with a colonic stent. The colonic stent group had a higher Charlson index (9.5 ± 2.1 vs 8.6 ± 1.5, p = 0.01), a shorter time to oral intake (0.9 ± 1.1 vs 16.4 ± 53.5 days, p = 0.05), a shorter hospital stay (4 ± 4.8 vs 16.7 ± 15.5 days, p = 0.0001), less need for stomata (11.1 % vs 32.7 %, p = 0.01), fewer early complications (4.3 % vs 46.9 %, p = 0.0001) and more late complications (33.3 % vs 6.4 %, p = 0.001). Undergoing chemotherapy (p = 0.008) was the only independent factor related to increased survival. In the subgroup of patients managed with chemotherapy, surgical primary tumor resection was an independent factor associated with increased survival.

CONCLUSION

both treatments are effective for resolving obstructive manifestations in patients diagnosed with stage-IV obstructive colorectal cancer. Resection surgery has no positive impact on survival and thus cannot be recommended as a therapy of choice.

Colonic stenting as a bridge to surgery in malignant large bowel obstruction: oncological outcomes

INTRODUCTION

Stenting of obstructing colorectal cancers obviates the need for emergency surgery, reducing initial morbidity and mortality rate associated with emergency surgery and facilitates full staging of the neoplastic process with an opportunity to optimize the patient for surgery. Some recent publications have suggested however that this approach may be associated with higher local recurrence rates. We examined our outcomes following colonic stenting as a bridge to resection.

METHODS

A database was reviewed (2006-2018) of patients presenting with acute colorectal obstruction that proceeded to endoscopic stenting. We assessed the bridge to surgery strategy, its success, complication rate, and impact on recurrence and survival.

RESULTS

Of a total of 103 patients who presented with acute malignant large bowel obstruction over this time period, 26 patients had potentially curable disease at presentation and underwent stenting as a bridge to surgery. The technical success rate for stenting in those managed as a bridge to surgery was 92% (n = 24/26) with 7.69% (n = 2/26) having a complication. There was one stent-related perforation. Median follow-up of this cohort was 31 months, with a 5-year overall survival of 53.5%.

CONCLUSION

Colorectal stenting as a bridge to resection is a successful management strategy for those presenting with obstructing colorectal obstruction. Selective use is associated with lower rates of stoma formation, greater rates of laparoscopic resections with low complication rates, and acceptable oncological outcomes.

Colonic Stent Use in Patients With Malignant Flexure Tumors Presenting With Obstruction

Background and Objective:

Colonic stenting in left-sided tumor is being commonly used. However, placing a stent in the flexure tumors is rare because it is technically more difficult. In this study, we aimed to retrospectively screen patients with flexure tumors admitted to our clinic who were treated using a colonic stent and discuss our findings.

Methods:

Patients admitted to the emergency department for obstructive colonic tumors between 2012 and 2017 were retrospectively evaluated, and 21 patients treated using stents were included in the study. The expandable metal stent (Wallflex®, Boston Scientific, Marlborough, MA, USA) was placed at the obstruction through the lead wire.

Results:

The mean age of the patients was 62 years, and the ratio of females to males was 3:18. Splenic flexure tumors were detected in 18 patients and hepatic flexure tumors in 3 patients. Seven of the patients were stented for palliative purposes. Fourteen of the cases underwent surgery. Three of them underwent laparoscopic surgery and eleven underwent open surgery.

Conclusions:

Preoperative stenting in colonic flexura tumors is associated with faster healing, less postoperative complications, lower rates of colostomy, and higher rates of minimally invasive surgery, and can be safely used at experienced centers.

Successful treatment of obstructing colonic cancer by combining self-expandable stent and neoadjuvant chemotherapy: A case report

BACKGROUND

Surgery 5-10 d after stent insertion was recommended by the European Society of Gastrointestinal Endoscopy for obstructing colonic cancer. For some obstructive patients, this may be not a good choice. Here, we report the successful treatment of obstructing colonic cancer by combining self-expandable stent and neoadjuvant chemotherapy.

CASE SUMMARY

The patient was a 72-year-old man who was admitted with a chief complaint of abdominal pain for more than 1 mo. Computed tomography (CT) scanning revealed that there was a mass in the descending colon, which led to intestinal obstruction. On admission, a series of therapeutic measures, such as fasting and water deprivation, gastrointestinal decompression, total parenteral nutrition, and octreotide acetate, were taken to improve the obstructive symptoms. At the same time, a self-expandable metal stent was successfully placed across the stenosis, and a biopsy was obtained and diagnosed as adenocarcinoma. CT scanning 14 d after insertion of the stent revealed that the intestine was swollen significantly. Systemic chemotherapy with modified FOLFOX6 (mFOLFOX6) was administered. After two courses of mFOLFOX6, CT scanning showed clearly that swelling of the intestine was improved. Subsequently, the patient underwent left hemi-colectomy without stoma placement. The postoperative course was uneventful, and he has been disease-free for 6 mo after surgery.

CONCLUSION

This modified treatment strategy may provide an alternative therapy for patients with obstructing colonic cancers.