Complete remission in apretreated, microsatellite-stable, KRAS-mutated colon cancer patient after treatment with sintilimab and bevacizumab and platinum-based chemotherapy - a case report and literature review

Sep 21, 2026

Metastatic colon cancer remains difficult to cure, particularly in microsatellite-stable (MSS) tumors that typically show poor response to immune checkpoint inhibitors (ICIs). A reported case describes complete remission after postoperative recurrence in an MSS, KRAS-mutated patient treated with sintilimab combined with bevacizumab and platinum-based chemotherapy. The tumor microenvironment markers PD-1+CD8+ and HLA-DR-positive myeloid subsets were detected, with 43 months progression-free survival under ongoing follow-up. Findings suggest this regimen may be a promising option for pretreated MSS/KRAS-mutated metastatic colorectal cancer pending confirmation in clinical trials.

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TYPE Case Report PUBLISHED 28 March 2024 DOI 10.3389/fimmu.2024.1354613 OPEN ACCESS EDITED BY Sharon R. Pine, University of Colorado Anschutz Medical Campus, United States REVIEWED BY Arkady Bedzhanyan, Petrovsky National Research Center of Surgery, Russia Javier Ros, Vall d’ Hebron University Hospital, Spain *CORRESPONDENCE Hao Chen [ery_chenh@lzu.edu.cn](ery_chenh@lzu.edu.cn) RECEIVED 14 December 2023 ACCEPTED 01 March 2024 PUBLISHED 28 March 2024 CITATION He L, Li H, Wang Y, Li W, Gao L, Xu B, Hu J, He P, Pu W, Sun G, Wang Z, Han Q, Liu B and Chen H (2024) Complete remission in apretreated, microsatellite-stable, KRASmutated colon cancer patient after treatment with sintilimab and bevacizumab and platinum-based chemotherapy: a case report and literature review. Front. Immunol. 15:1354613 . doi: 10.3389/fimmu.2024.1354613 COPYRIGHT © 2024 He, Li, Wang, Li, Gao, Xu, Hu, He, Pu, Sun, Wang, Han, Liu and Chen. 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. Complete remission in apretreated, microsatellite-stable, KRAS-mutated colon cancer patient after treatment with sintilimab and bevacizumab and platinum-based chemotherapy: a case report and literature review Lijuan He 1,2, Haiyuan Li 1,2, Yunpeng Wang 1,2, Weidong Li 1,3, Lei Gao 1,2, Bo Xu 1,2, Jike Hu 1,2, Puyi He 1,2, Weigao Pu 1,2, Guodong Sun 1,2, Zhuanfang Wang 1,2, Qinying Han 1,2, Ben Liu 1,2 and Hao Chen 1,2,4* 1 Lanzhou University Second Hospital, Lanzhou, China, 2 Department of Surgical Oncology, Lanzhou University Second Hospital, Lanzhou, China, 3 Department of Pathology, Lanzhou University Second Hospital, Lanzhou, China, 4Gansu Provincial Key Laboratory Of Environmental Oncology, Lanzhou, China Metastatic colon cancer remains an incurable disease, and it is difﬁcult for existing treatments to achieve the desired clinical outcome, especially for colon cancer patients who have received ﬁrst-line treatment. Although immune checkpoint inhibitors (ICIs) have demonstrated durable clinical efﬁcacy in a variety of solid tumors, their response requires an inﬂammatory tumor microenvironment. However, microsatellite-stable (MSS) colon cancer, which accounts for the majority of colorectal cancers, is a cold tumor that does not respond well to ICIs. Combination regimens open the door to the utility of ICIs in cold tumors. Although combination therapies have shown their advantage even for MSS colon cancer, it remains unclear whether combination therapies show their advantage in patients with pretreated metastatic colon cancer. Wereport a patient who has achieved complete remission and good tolerance with sintilimab plus bevacizumab and platinum-based chemotherapy after postoperative recurrence. The patient had KRAS mutation and MSS-type colon cancer, and his PD-1+CD8+ and CD3 − CD19 − CD14+CD16 − HLA-DR were both positive. He has achieved a progression-free survival of 43 months and is still being followed up at our center. The above results suggest that this therapeutic regimen is a promising treatment modality for the management of pretreated, MSS-type and KRAS-mutated metastatic colorectal cancer although its application to the general public still needs to be validated in clinical trials. KEYWORDS colon cancer, MSS, KRAS mutation, immunotherapy, bevacizumab, sintilimab, recurrence, metastasis Frontiers in Immunology 01 [frontiersin.org](frontiersin.org) Introduction Colon cancer (CC) is the third most common type of cancer and the second leading cause of cancer-related deaths worldwide (1) . Radical surgery alon

FAQs

Why are immune checkpoint inhibitors less effective in microsatellite-stable colon cancer?

MSS colon cancer is a “cold tumor” with an inflammatory tumor microenvironment that is less favorable for ICI response, leading to poor clinical benefit in patients with MSS disease.

What treatment led to complete remission in the reported patient?

The patient achieved complete remission after postoperative recurrence using sintilimab combined with bevacizumab and platinum-based chemotherapy, applied to an MSS-type, KRAS-mutated colon cancer.

How durable was disease control in the case and what follow-up was reported?

Progression-free survival of 43 months was achieved, and the patient continued to be followed at the treating center at the time of reporting.

Sep 21, 2026

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