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Chen YF, Huang C, Chen ZJ, Wang ZH. Significant response to tislelizumab plus bevacizumab in a patient with microsatellite instability-high colon cancer: A case report and review of literature. World J Gastroenterol 2027; 33(2): 124393 [DOI: 10.3748/wjg.124393]
World J Gastroenterol. Jan 14, 2027; 33(2): 124393 Published online Jan 14, 2027. doi: 10.3748/wjg.124393
Significant response to tislelizumab plus bevacizumab in a patient with microsatellite instability-high colon cancer: A case report and review of literature
Yun-Fei Chen, Chi Huang, Zhi-Jian Chen, Zhi-Hui Wang
Yun-Fei Chen, Chi Huang, Zhi-Jian Chen, Zhi-Hui Wang, Department of Gastrointestinal Surgery, Wuhan Central Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, Hubei Province, China
Yun-Fei Chen, Chi Huang, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, Hubei Province, China
Co-first authors: Yun-Fei Chen and Chi Huang.
Author contributions: Chen YF was the major contributor to the writing of the manuscript; Chen YF and Huang C collected the clinical data and contributed equally as co-first authors; Chen ZJ assist in performing the surgery; Wang ZH reviewed the study. All the authors have read and approved the final manuscript.
AI contribution statement: Regarding the use of AI, generative AI tool (DeepSeek) was used solely for language editing.
Informed consent statement: Informed written consent was obtained from the patient for publication of this case report and any accompanying images. The patient has consented to the submission of the case report to the journal.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Corresponding author: Zhi-Hui Wang, MD, PhD, Department of Gastrointestinal Surgery, Wuhan Central Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 26 Shengli Street, Jiang’an District, Wuhan 430000, Hubei Province, China. wangzhihui@tmu.edu.cn
Received: June 15, 2026 Revised: July 29, 2026 Accepted: September 15, 2026 Published online: January 14, 2027 Processing time: 147 Days and 1.8 Hours
Abstract
BACKGROUND
Programmed cell death protein-1 inhibitors are established treatments for advanced microsatellite instability-high (MSI-H) colorectal cancer; however, primary and acquired resistance persist. Recent studies have indicated that combining programmed cell death protein-1 inhibitors with anti-angiogenic targeted agents has been explored as a strategy to improve responses; however, evidence for this approach in MSI-H colorectal cancer remains limited.
CASE SUMMARY
We present the case of a 58-year-old female patient with previous primary ovarian and gastric malignancies who was recently diagnosed with malignant adenocarcinoma of the descending and sigmoid colons (cT4N2M1, American Joint Committee on Cancer 8th edition). Exploration revealed signs of peritoneal metastasis. The primary tumor was unresectable, and a colostomy was performed for obstruction. Next-generation sequencing revealed a KRAS mutation and MSI-H. Germline testing revealed a pathogenic MSH2 c.1216C > T p (R406*) variant, leading to a diagnosis of Lynch syndrome. Because chemotherapy was unsuitable, she received 12 cycles of tislelizumab (200 mg) plus bevacizumab (400 mg) intravenously every 3 weeks as chemotherapy-free conversion therapy. The longest diameter of the target lesion decreased from 94 to 26 mm, confirming a partial response according to Response Evaluation Criteria in Solid Tumors 1.1, which was maintained at the most recent imaging assessment. No treatment modifications due to toxicity were documented.
CONCLUSION
This case highlights the potential feasibility of combining immune checkpoint inhibitors with anti-angiogenic agents to achieve a deep radiological response and improve patient prognosis, representing a therapeutic strategy that warrants further exploration.
Core Tip: This case report describes a rare patient with triple primary malignancies, including microsatellite instability-high/KRAS-mutated advanced colorectal cancer, with a history of clinically cured gastric and ovarian cancers, who achieved marked radiological remission following conversion therapy with tislelizumab combined with bevacizumab. The target-lesion longest diameter decreased by 72.3%, meeting Response Evaluation Criteria in Solid Tumors 1.1 criteria for a confirmed partial response. Germline testing identified a pathogenic MSH2 variant, establishing Lynch syndrome. This observation highlights the potential of combining programmed death-1 inhibitors with anti-angiogenic targeted agents in selected patients with advanced microsatellite instability-high colorectal cancer and warrants further investigation.
