World Journal of Gastrointestinal Endoscopy · 5 authors, 6 centres
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In patients with obstructing colon cancer treated with stenting as a bridge to curative surgery (SBTS), 45.2% developed metastases, with the peritoneum being the most common site (60.7% of recurrences). Over a median follow-up of 46 months, 41.9% of patients died, of which 61.5% were colorectal cancer-specific deaths. Liver-only recurrence, peritoneum-only recurrence, and two or more recurrence sites were significant predictors of colorectal cancer-specific death.
**Background:** Colorectal cancer is the second most prevalent malignancy and third leading cause of cancer-related death worldwide. Malignant bowel obstruction occurs in 8%-25% of colorectal cancer patients at presentation. Emergency surgery for obstruction carries substantial morbidity (40%-60%) and mortality (15%-34%). Self-expanding metal stents (SEMS) as a bridge to curative surgery (SBTS) offer a less morbid alternative, but concerns remain about worse long-term oncological outcomes due to potential tumour dissemination from stent-related perforations or micro-perforations. This study aimed to evaluate recurrence patterns, survival outcomes, and colorectal cancer (CRC)-specific death in patients undergoing SBTS for obstructing colon cancer (OCC), using competing risk analysis to account for other-cause mortality.
**Methods:** Data from 62 consecutive patients with non-metastatic OCC who underwent SBTS at Singapore General Hospital over ten years (2007-2016) were retrospectively analysed. Patients with stage IV disease or anastomotic recurrence were excluded. Clinical, histopathological, and oncological data were collected from electronic health records. Primary outcomes were recurrence patterns, overall survival (OS), cancer-specific survival (CSS), and CRC-specific death. OS and CSS were estimated using Kaplan-Meier curves. Competing risk analysis with cumulative incidence function (CIF) was used to estimate CRC-specific mortality, treating other cause-specific death as a competing event. Fine-Gray regressions were performed to determine prognostic factors of CRC-specific death.
**Key Results:** The median age was 70 years (range: 37-90); 59.7% were male; 87.1% had ASA I-II classification. Tumour staging was predominantly T3 (75.8%) and T4 (22.6%). The median time to elective CRC resection was 10 days (range: 5-23). Laparoscopic approach was used in 46.8% of cases. The postoperative complication rate was 21%, with 30-day and 90-day mortality rates of 1.6% and 3.2%, respectively. Adjuvant chemotherapy was given to 50% of patients. During follow-up, 28 patients (45.2%) developed metastases after a median of 16 months (range: 3-69). Among 18 patients with single-site metastases: 4 had lung-only (14.3%), 4 had liver-only (14.3%), and 10 had peritoneum-only (35.7%) metastases; 10 patients had two or more metastatic sites (35.7%). The peritoneum was the most prevalent site, involved in 17 of 28 patients (60.7%). Median follow-up was 46 months (range: 0-154). Of 62 patients, 26 (41.9%) died: 16 (61.5%) from CRC and 10 (38.5%) from other causes. The 1-, 3-, and 5-year OS probabilities were 88%, 74%, and 59%; CSS probabilities were 97%, 83%, and 67%. The CIF for CRC-specific death at 12, 36, and 60 months was 0.03, 0.16, and 0.29, respectively. The highest CIF at 60 months was for liver-only recurrence (0.69), followed by peritoneum-only recurrence (0.65), lymphovascular invasion (0.64), ≥2 recurrence sites (0.63), and T4 staging (0.62). On univariate Fine-Gray regression, poor differentiation (SHR 2.67, 95%CI: 1.50-4.76, P<0.001), lymphovascular invasion (SHR 3.99, 95%CI: 1.55-10.3, P=0.004), liver-only recurrence (SHR 4.25, 95%CI: 0.98-18.4, P=0.049), peritoneum-only recurrence (SHR 4.53, 95%CI: 1.79-11.5, P=0.001), and ≥2 recurrence sites (SHR 1.96, 95%CI: 1.19-3.23, P=0.008) were associated with CRC-specific death. On multivariate analysis, liver-only recurrence (SHR 41.0, 95%CI: 5.01-336, P<0.001), peritoneum-only recurrence (SHR 23.2, 95%CI: 2.92-185, P=0.003), and ≥2 recurrence sites (SHR 5.28, 95%CI: 1.80-15.4, P=0.002) remained significant. Lung-only recurrence was not significantly associated with CRC-specific death (P=0.570).
**Clinical Implications:** This study demonstrates that peritoneal metastases are the predominant recurrence pattern after SBTS for OCC, occurring in 60.7% of patients who developed metastases. Liver-only recurrence, peritoneum-only recurrence, and multiple recurrence sites are strong predictors of CRC-specific death. The findings raise caution about the routine use of SBTS, given the high rate of peritoneal recurrence and its association with poor survival. The competing risk analysis provides a more accurate estimate of CRC-specific mortality by accounting for other-cause death, which is particularly relevant in an older patient population with comorbidities. These results support the need for careful patient selection and close surveillance for peritoneal recurrence in patients undergoing SBTS.