Immune checkpoint inhibitors for dMMR/MSI localized rectal cancer: A systematic review of treatment strategies
- Study type
- Review article
- Design
- Systematic review of prospective and retrospective cohort studies (search of PubMed, Embase, Web of Science and the Cochrane Library from January 2000 to April 2025) with descriptive synthesis of the data
- Sample size
- 19 studies including 504 patients
- Source
- Critical Reviews in Oncology/Hematology · 2025
In plain words
In a small group of patients with rectal cancer whose tumour has a particular molecular feature (dMMR/MSI-H), immunotherapy before surgery can make the tumour much smaller or even make it disappear. In many of these patients, surgery or chemoradiotherapy was not needed and the organ was preserved. These results come from a review of small, non-randomised studies, so the treatment decision should be made with the care team.
Key results
Treatment arms and regimens
Dosing details in the full text of the paper.
Dual immune checkpoint blockade, chemotherapy or anti-angiogenic agents; dosing details in the full text of the paper.
Dosing details in the full text of the paper.
Source of the regimen details: Abstract of the paper
Doses are given for the information of specialists, as in this study’s protocol, and are not a prescription. Every drug must be prescribed by the treating physician for the individual patient.
Study population
Prospective or retrospective cohort studies that evaluated neoadjuvant immune checkpoint inhibitor (ICI)-based strategies in MSI-H/dMMR rectal cancer and reported clinical or pathological complete response (cCR/pCR), organ preservation or treatment-related toxicity.
Endpoints
Clinical complete response (cCR), pathological complete response (pCR), organ preservation and treatment-related toxicity. The quality of evidence was assessed with GRADE and standard risk-of-bias tools.
Safety and side effects
Combination strategies (dual checkpoint blockade, chemotherapy or anti-angiogenic agents) were associated with increased toxicity. The abstract does not report exact rates of grade 3 or higher adverse events, and the authors judged neoadjuvant PD-1 blockade to be safe.
Clinical significance and place in guidelines
This systematic review shows that neoadjuvant PD-1 inhibitor monotherapy in MSI-H/dMMR rectal cancer has the strongest evidence base and supports organ-preservation approaches and an "immunotherapy-first" strategy in selected patients. Adding CRT gave marginal benefit. The status of this approach in clinical guidelines and drug approvals should be checked separately, as the abstract does not address them.
Limitations
The review is based on prospective and retrospective cohort studies, and the data synthesis was descriptive. No randomised trial is mentioned in the abstract. The heterogeneity of regimens, dosing details and exact adverse event rates are not reported in the abstract.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.