Systematic Review of Neoadjuvant Immunotherapy for Mismatch Repair Deficient Locally Advanced Colon Cancer: An...

Area of Science:

• Oncology
• Immunotherapy
• Gastrointestinal Cancers

Background:

• Mismatch repair deficient (dMMR) colon cancer, a distinct molecular subtype with high microsatellite instability, is responsive to immune checkpoint inhibition.
• The National Comprehensive Cancer Network now endorses neoadjuvant immunotherapy for select patients with nonmetastatic dMMR colon cancer.

Purpose of the Study:

• To review existing evidence on neoadjuvant immunotherapy for dMMR, microsatellite unstable, nonmetastatic colon cancer.
• To assess the safety and efficacy of this treatment approach.

Main Methods:

• Searches of PubMed, Embase, and Web of Science were conducted up to September 26, 2023.
• Included studies were in English, focused on adults with nonmetastatic colon cancer receiving neoadjuvant immunotherapy, and reported on at least 10 cases.
• Safety and complete pathologic responses were the primary outcome measures.

Main Results:

• Eight studies involving various immunotherapy agents, regimens, and durations were included.
• High rates of complete R0 resection (98-100%) were achieved.
• Pathologic complete response (ypT0N0) ranged from 50% to 91% in resected patients, with generally favorable safety profiles and low rates of severe postoperative complications.

Conclusions:

• Neoadjuvant immune checkpoint inhibition demonstrates high pathologic complete response rates in locally advanced colon cancer.
• The current literature is limited by small, heterogeneous, and uncontrolled studies, precluding meta-analysis.
• More research is essential to fully understand the safety and optimal role of these regimens in neoadjuvant treatment.