The use of nivolumab in colorectal cancer with Lynch syndrome. A case report

Lynch syndrome (LS) resulting from the abnormal repair of unpaired DNA bases is characterized by an increased risk of colorectal, endometrial, and urinary tract cancers. Regardless of the tumor type, immunotherapy with immune checkpoint inhibitors (ICIs) has been approved for the treatment of patients with unresectable or metastatic DNA mismatch repair-deficient (dMMR) tumors, which may present a treatment option for patients with LS. The article contains a case report of a female patient with a germline MLH1 mutation and multiple primary colonic malignancies treated with nivolumab for 26 months. This observation demonstrates the success of immunotherapy after 6 lines of chemotherapy, implying potential control of tumor growth in patients with LS.