Background: Owing to the special features of biologics, deficient mismatch repair (dMMR) in patients with colon cancer has achieved little treatment efficacy from chemoradiotherapy. Immunotherapy has shown promising results for the treatment of colon cancer. The high response rate observed suggests a great option for patients presenting with unresectable tumors, as it allows for better oncological resection. Here, we aimed to highlight the significant effects of immunotherapy on dMMR in colon cancer.
Case summary: A 54-year-old man diagnosed with locally unresectable dMMR colon cancer received preoperative immunotherapy (three cycles of pembrolizumab) and achieved a pathological complete response after surgery.
Conclusion: Immunotherapy can be used as a conversion treatment for locally unresectable colon cancer with dMMR.
Keywords: Case report; Colon cancer; Immunotherapy; Pathological complete response.
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