Remission from the 5-Fu-Based Chemotherapy to Gemcitabine-Based Chemotherapy-Based on the Pathological Classification of Periampullary Carcinoma: A Case Report and Literature Review.

Background: Periampullary carcinoma, which includes ampullary carcinoma, pancreatic head cancer, distal common bile duct cancer, and duodenal papillary cancer, is a relatively rare malignancy with uncertain therapeutic options. Although several studies have investigated the efficacy of multiple adjuvant chemotherapy regimens for periampullary carcinoma treatment, the optimal regimen remains to be determined. The inherent heterogeneity of the mucosal origin divides periampullary carcinoma into intestinal and pancreaticobiliary types. Therefore, the selection of chemotherapy regimens based on pathological type may have potential therapeutic significance.

Case Presentation: A 72-year-old woman with moderately differentiated periampullary adenocarcinoma experienced disease progression after receiving FOLFOX regimen. Subsequently, the sample was subtyped first by H&E evaluation and then by the evaluation of an IHC panel composed of CK20, CDX2, MUC1, MUC2, and MUC5AC. The pathologists concluded that the patient's sample was of the pancreaticobiliary (PB) subtype. The subsequent change to gemcitabine plus S-1 adjuvant therapy achieved remission of liver metastases based on the pathological classification of the cancer.

Conclusion: Based on the pathological classification, adjuvant chemotherapy with gemcitabine may be beneficial for patients with PB subtype periampullary carcinoma. 5-Fu-based adjuvant chemotherapy may be beneficial for patients with intestinal subtype periampullary carcinoma.