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CASE REPORT article
Front. Immunol.
Sec. Cancer Immunity and Immunotherapy
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1571607
This article is part of the Research Topic Colorectal Cancer Immunotherapy and Immune Mechanisms View all 3 articles
Pathological Complete Response after Monotherapy with Immune Checkpoint Inhibitors for Bifocal Colon Cancer in a Patient with Lynch syndrome And Situs Inversus Totalis: A Case Report
Provisionally accepted
Jun Feng 1
Wenbo Niu 1 Juan Zhang 1 Yuanyi Ding 1 Zheng Li 1
Zhang Jianfeng 1
Baokun Li 1 Chenhui Li 1
Wang Feifei 1
Guiying Wang 1,2* Bin Yu 1*- 1 The Second Department of General Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
- 2 Second Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
Background: Lynch syndrome is the most common hereditary colorectal cancer (CRC) syndrome, accounting for 3-5% of all CRC cases. Situs inversus totalis (SIT) is a rare congenital malformation with an incidence of 1 in 8,000 to 1 in 25,000. The co-occurrence of Lynch syndrome and SIT is extremely uncommon. Immune checkpoint inhibitors (ICIs) have demonstrated significant efficacy in treating microsatellite instability-high/deficient mismatch repair (MSI-H/dMMR) CRC. Tumors associated with Lynch syndrome frequently exhibit MSI-H, providing a theoretical basis for ICI use. Case presentation: We report a case of bifocal colon cancer associated with Lynch syndrome and SIT. After seven cycles of sintilimab, the patient developed gastrointestinal perforation due to tumor regression, necessitating emergency surgery. The anatomical variations associated with SIT required the surgical team to adopt an alternative approach. Postoperatively, the patient continued sintilimab treatment for 2 years. In June 2024, he underwent a colostomy reversal and proximal colectomy. Pathological examination revealed a tumor regression grade (TRG) of 0, indicating complete pathological remission (pCR), with no recurrence or metastasis detected upon follow-up.The anatomical variations associated with SIT increase the complexity of surgical procedures. Advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) are essential for assessing fine anatomical details and facilitating surgery. ICIs are an effective treatment option for Lynch syndrome-associated CRC, as demonstrated in this
Keywords: Situs inversus totalis, Lynch Syndrome, immune checkpoint inhibitors, Pathological complete response, Colon Cancer, Microsatellite instability-high, Immune-related adverse events
Received: 05 Feb 2025; Accepted: 03 Apr 2025.
Copyright: © 2025 Feng, Niu, Zhang, Ding, Li, Jianfeng, Li, Li, Feifei, Wang and Yu. 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) or licensor 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.
* Correspondence:
Guiying Wang, Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei Province, China
Bin Yu, The Second Department of General Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
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