A single checkpoint inhibitor can be used to successfully treat two simultaneous types of primary cancer in a patient with Lynch syndrome, according to a research letter published online Sept. 25 in the Annals of Internal Medicine.
Benjamin Musher, M.D., and Ahmad Rahal, M.D., from the Baylor College of Medicine in Houston, present the case of a 55-year-old woman with extensive gastrointestinal cancer who had a family history of colon, uterine, and gastric cancer. A 5-cm mucosal lesion in the ascending colon was revealed in colonoscopy, and several additional liver masses were identified, which were confirmed as primary intrahepatic cholangiocarcinoma rather than colon cancer metastasis.
The researchers identified a deleterious mutation in MLH1, which confirmed that both types of cancer were caused by Lynch syndrome. The patient elected to start treatment with a checkpoint inhibitor and started intravenous pembrolizumab. A dramatic and progressive response to therapy was observed for the tumor. The colon cancer was no longer seen during colonoscopy at 16 months after pembrolizumab initiation; no hypermetabolic activity was seen in positron emission tomography in any previously documented site of disease. No cancer-related symptoms were seen at 18 months of therapy.
"This case emphasizes the importance of eliciting a thorough family history in patients with cancer and considering the presence of multiple types of primary cancer in a patient with an extensive family history of cancer," the authors write.
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