Discordance between radiological and pathological response to neoadjuvant immunotherapy in mismatch repair-deficient/microsatellite instability-high colorectal cancer - a meta-analysis

Q: What mismatch repair status defines the studied colorectal cancer population?

The analysis focuses on mismatch repair-deficient (dMMR) and microsatellite instability-high (MSI-H) colorectal cancer.

Q: How was discordance between radiological and pathological responses evaluated?

Studies reporting both imaging data and pathological results after neoadjuvant immune checkpoint inhibitor therapy were pooled using a random-effects model to estimate odds ratios and confidence intervals.

Q: Why does the paper emphasize combining radiological assessment with additional modalities?

Radiological assessment alone did not reliably reflect treatment efficacy, especially in colon cancer, because confirmed pathological complete responses were often incorrectly diagnosed as residual disease.

Sep 22, 2026

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Systematic review and meta-analysis evaluate whether radiological and pathological assessments match after neoadjuvant immunotherapy in nonmetastatic mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer. Evidence from studies published February 2015 to February 2025 was retrieved from PubMed, Embase, and Web of Science and synthesized using random-effects models. Twelve studies (396 patients) showed substantial discordance (59.6%), with colon cancer displaying higher discordance than rectal cancer. Radiology alone frequently misclassified confirmed pathological complete response as residual disease; heterogeneity was high (I2=85%).

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Introduction

Rationale for radiological vs pathological response assessment in dMMR/MSI-H CRC

Methods

Search strategy and study selection

Statistical synthesis and subgroup analyses

Results

Included studies and pooled discordance rate

Discordance by tumor location and response category

Misclassification of pCR by radiological assessment

Conclusion

Recommended integration of modalities for treatment efficacy appraisal

TYPE Review PUBLISHED 09 February 2026 DOI 10.3389/fimmu.2026.1680500 OPEN ACCESS EDITED BY Abhishek Mahajan, The Clatterbridge Cancer Centre, United Kingdom REVIEWED BY Chintamani Godbole, Jaslok Hospital, India Andre´ Filipe Oliveira, Hospital do Divino Esprito Santo, Portugal *CORRESPONDENCE Wu Jiang [jiangwu@sysucc.org.cn](jiangwu@sysucc.org.cn)[ ](jiangwu@sysucc.org.cn)Peirong Ding [dingpr@sysucc.org.cn](dingpr@sysucc.org.cn) †These authors have contributed equally to this work and share ﬁrst authorship RECEIVED 06 August 2025 REVISED 20 January 2026 ACCEPTED 23 January 2026 PUBLISHED 09 February 2026 CITATION Xie Y, Liao L, Ding P and Jiang W (2026) Discordance between radiological and pathological response to neoadjuvant immunotherapy in mismatch repair-deﬁcient/ microsatellite instability-high colorectal cancer: a meta-analysis. Front. Immunol. 17:1680500 . doi: 10.3389/fimmu.2026.1680500 COPYRIGHT © 2026 Xie, Liao, Ding and Jiang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Discordance between radiological and pathological response to neoadjuvant immunotherapy in mismatch repair-deﬁcient/microsatellite instability-high colorectal cancer: a meta-analysis Yilin Xie 1,2,3,4†, Leen Liao 1,2,3,4†, Peirong Ding 1,2,3,4* and Wu Jiang 1,2,3,4* 1 Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China, 2Sun Yat-sen University Cancer Center, Guangzhou, China, 3State Key Laboratory of Oncology in South China, Guangzhou, China, 4Collaborative Innovation Center for Cancer Medicine, Guangzhou, China Background: Mismatch repair deﬁciency (dMMR) and microsatellite instability (MSI-H) cancers exhibit high immunogenicity and are highly responsive to immune checkpoint inhibitors. In patients with locally advanced dMMR/MSI-H colorectal cancer (CRC), neoadjuvant immunotherapy (NIT) has demonstrated unprecedented pathological complete response (pCR) rates, suggesting nonoperative management strategies may be possible . There remains a discrepancy between radiological assessment and pathological responses to NIT in CRC. Methods: We conducted a systematic review and meta-analysis of studies published between February 2015 and February 2025 to determine if radiological and pathological assessments following neoadjuvant immune checkpoint inhibitor therapy (NIT) were consistent in patients with nonmetastatic dMMR/MSI-H CRC. Using PubMed, Embase, and Web of Science, the literature was retrieved, with inclusion criteria focusing on studies that reported both imaging data and pathological results. A random-effects model was used to calculate pooled odds ratios (ORs) and 95% conﬁdence intervals (CIs) . Subgroup analyses were conducted based on tumor location (colon versus rectum) and type of response (cCR versus pCR) . Results: In 12 studies, 396 patients were included. A total rate of 59 . 6% discordance was found between radiological and pathological responses . Compared to rectal cancer patients (34.9%), colon cancer patients exhibited asigniﬁcantly higher rate of discordance (64 . 2%) . A total of 238 patients with conﬁrmed pCR were incorrectly diagnosed as having residual disease on radiological assessment (OR = 61 .41; 95% CI: 10 .05–375. 27;P < 0 . 00001) . A high level of heterogeneity was observed across studies (I2 = 85%), but no publication bias was observed. Frontiers in Immunology 01 [frontiersin.org](frontiersin.org) Conclusion: In dMM

FAQs

What mismatch repair status defines the studied colorectal cancer population?

The analysis focuses on mismatch repair-deficient (dMMR) and microsatellite instability-high (MSI-H) colorectal cancer.

How was discordance between radiological and pathological responses evaluated?

Studies reporting both imaging data and pathological results after neoadjuvant immune checkpoint inhibitor therapy were pooled using a random-effects model to estimate odds ratios and confidence intervals.

Why does the paper emphasize combining radiological assessment with additional modalities?

Radiological assessment alone did not reliably reflect treatment efficacy, especially in colon cancer, because confirmed pathological complete responses were often incorrectly diagnosed as residual disease.

Sep 22, 2026

Upload by Miles