Introduction

The use of self-expandable metal stents (SEMS) as a bridge-to-surgery (BTS) for acute malignant large bowel obstruction has seen an increase in recent years, with high rates of technical and clinical success¹. However, the long-term oncological prognostic impact of colonic stenting has received mixed reviews in the literature, with concerns about lymphovascular and perineural invasion at the tumour site, which could potentially lead to increased risk of metastatic recurrence and poorer long-term oncological outcomes.

Aims & Methods

We examined the risk of metastatic disease occurrence in a single tertiary centre in Singapore by performing an audit on outcomes over a 10-year period following SEMS insertion as BTS. Data of patients who underwent SEMS insertion for malignant bowel obstruction (MBO) between September 2013 – December 2023 were retrospectively reviewed. The occurrence of metastases on computed tomography (CT) scan was documented and the time to disease occurrence noted. Overall survival, metastases-free survival and occurrence of metastatic disease were analysed using Kaplan-Meier estimates. Potential factors associated with metastatic occurrence, namely American Joint Committee on Cancer (AJCC) staging and completion of adjuvant chemotherapy, were analysed using Fisher’s exact test and Kaplan–Meier estimator respectively.

Results

A total of 132 patients underwent SEMS placement from September 2013 to December 2023 for MBO. We excluded 31 patients who had metastatic disease at diagnosis or who underwent colonic stenting for palliative decompression, and five who were lost to follow up. Of the 96 remaining patients who underwent colonic stenting as BTS, the mean age was 68.4 years and 47 (49.0%) were male. The median length of follow-up was 32 months. Overall survival and disease-free survival were 90.9% and 66.2% respectively. Mean overall survival time was 86.8 months (95% CI [75.1-98.6]), mean metastases-free survival was 95.6 months (95% CI [88.7-102.5]). 24 patients (31%) developed distant metastases during the follow-up period. Median time to metastases was 14.1 months. Of these 24 patients, 20 (83.3%) were AJCC stage 3, and four patients (16.7%) were AJCC stage 2. In addition, 11 patients (45.8%) completed adjuvant chemotherapy; 13 patients (54.1%) declined adjuvant chemotherapy or had attenuated doses. Using Kaplan–Meier estimates, overall survival and occurrence of metastases were not found to be significantly associated with completion of adjuvant chemotherapy (P values of 0.056 and 0.114 respectively). Keeping in mind the relatively small sample size, these results need to be interpreted with caution. A positive association was found with higher AJCC staging and occurrence of metastases using Fisher analysis, with a P value of 0.037.

Conclusion

The rate of occurrence of distant metastases was similar to prior reported literature. The majority of patients who developed metastatic occurrence were AJCC stage 3 who declined or had attenuated adjuvant chemotherapy. The data suggests that colonic stenting as BTS does not worsen long-term oncological outcome. Disease recurrence was related to disease stage and lack of effective adjuvant chemotherapy.

References

1. Li, James Weiquan FRCPEd, FAMS1; Ngu, James Chi-Yong FRCS, MBBS2; Lim, Kok Ren FRCS, MBBS2; Tay, Shu Wen MRCP, MBBS1; Jiang, Bochao MRCP, MBBS1; Wijaya, Ramesh FRCS, MBBS2; Yusof, Sulaiman FRCS, MBBS2; Ong, Calvin Jianming FRCS, MBBS2; Kwek, Andrew Boon Eu MRCP, MBBS1; Ang, Tiing Leong FRCPEd, FAMS1. Colonic stenting in acute malignant large bowel obstruction: audit of efficacy and safety in a Singapore tertiary referral centre. Singapore Medical Journal 64(10):p 603-608, October 2023. | DOI: 10.11622/smedj.2021127

Disclosure

None