Risk and Management of Bowel Obstruction in Colorectal Cancer Patients Undergoing Immunotherapy: A Cross-Sectional...

Area of Science:

• Oncology
• Gastroenterology
• Immunotherapy

Background:

• Immunotherapy demonstrates significant efficacy in mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC).
• However, patients may experience bowel obstruction during tumor regression despite treatment response.

Purpose of the Study:

• To assess the incidence and risk factors of bowel obstruction in dMMR/MSI-H CRC patients receiving immunotherapy.
• To identify clinical and molecular predictors of immunotherapy-related bowel obstruction.

Main Methods:

• A retrospective study of 196 dMMR/MSI-H CRC patients treated with immunotherapy across four centers.
• Clinicopathological and molecular data were collected, and a Bayesian model was employed to identify obstruction risk factors.

Main Results:

• Bowel obstruction occurred in 10.3% of patients during immunotherapy.
• T4 stage tumors (P=0.008), metastatic disease (P<0.001), and baseline impassable lumen (P=0.022) were associated with higher obstruction risk.
• T4 tumor status was an independent risk factor (OR: 8.36). Obstructions often occurred post-initial response but pre-best overall response.

Conclusions:

• Bowel obstruction is a frequent complication in immunotherapy-treated CRC patients.
• Baseline T4 tumor stage and metastatic disease are significant risk factors.
• Early identification of high-risk patients and timely management are crucial for preventing and mitigating obstructions.