Is colonic stenting advisable for acute malignant large bowel obstruction?

Insertion of self-expandable metal stents (SEMS) for acute malignant large bowel obstruction (MBO) results in high technical and clinical success with a favourable safety profile, as shown in a recent Singapore study.

In addition, “[m]ost patients in this audit underwent minimally invasive surgery and primary anastomosis after successful bridge to surgery (BTS),” said the researchers.

A review was conducted on the data of patients undergoing SEMS insertion for MBO. Technical success was characterized by a successful SEMS deployment across tumour without complications, while clinical success referred to colonic decompression without requiring further surgical intervention.

In addition, the researchers assessed the rates of complications, median time to surgery, types of surgery, and rates of recurrence.

Emergent SEMS placement was carried out in 72 patients (mean age 68.8 years, 54 percent male) from September 2013 to February 2020. Tumours had a mean length of 4.2 cm, and 89.9 percent of malignant strictures were found distal to the splenic flexure. [Singapore Med J 2023;64:603-608]

The rate of technical success stood at 94.9 percent, while that of clinical success was 98.7 percent. A few patients (5.1 percent) had perforations, but none of them experienced stent migration of bleeding. More than half (63.3 percent) underwent SEMS insertion as BTS, and the median time to surgery was 20 days.

Minimally invasive surgery was done in 82 percent of patients. The rate of primary anastomosis was high at 98 percent. Of the patients, 39 had follow-up beyond 1 year after surgery (median 34 months). Of note, four (10.3 percent) had local recurrence and five (12.8 percent) had distant metastasis.

“While SEMS insertion as BTS enables the surgery to be converted from an emergency to a semi-elective setting, the benefits need to be balanced against the potential risks,” the researchers said.

“Our audit revealed a perforation rate of 5.1 percent, in keeping with the rates reported in the literature, which range between 4 percent and 11 percent,” they added. [Surg Endosc 2016;30:3976-3986; Surg Oncol 2013;22:14-21; World J Gastroenterol 2014;20:13239-13245]

On the other hand, those opposed to the use of SEMS as BTS often point out oncological outcomes as a major concern, but recent studies have demonstrated that SEMS as BTS has a disease-free survival similar to emergency surgery in acute MBO. [Int J Colorectal Dis 2020;35:633-640; Int J Colorectal Dis 2019;34:1241-1250; Int J Colorectal Dis 2013;28:407-414; Int J Colorectal Dis 2019;34:1827-1838]

Furthermore, the 2020 update of the European Society of Gastrointestinal Endoscopy Guideline points towards the increasing acceptance of SEMS for BTS. [Int J Colorectal Dis 2020;35:633-640]

“As a clinical audit, our analysis suffers from the usual limitations of a retrospective study, coupled with the lack of a comparative arm—the group of patients who underwent upfront emergency surgery,” the researchers said. “However, this is currently the largest case series of SEMS in acute MBO in Singapore, and it adds valuable information in support of this multidisciplinary approach.”

“In our institution, the availability of SEMS as a BTS has resulted in a high rate of single-stage MIS resections and primary anastomoses in this group of patients,” they added.