Multidisciplinary treatment with conversion surgery after radiological complete response of liver metastasis to gemcitabine, cisplatin, and durvalumab in metastatic distal cholangiocarcinoma.

INTRODUCTION: Distant metastasis in distal cholangiocarcinoma (DCC) generally precludes curative treatment. However, chemo-immunotherapy may enable multidisciplinary treatment with curative intent in selected patients. We report a rare case of metastatic DCC with liver metastasis that achieved radiological complete response after gemcitabine, cisplatin, and durvalumab (GCD) therapy, followed by resection of the residual primary lesion. CASE PRESENTATION: A 73-year-old woman with a history of total gastrectomy presented with DCC and a solitary liver metastasis. Following endoscopic ultrasound-guided hepaticojejunostomy and eight cycles of gemcitabine, cisplatin, and durvalumab (GCD) therapy, the liver metastasis achieved a radiological complete response. After 16 cycles of durvalumab maintenance therapy, conversion pancreaticoduodenectomy without hepatectomy was performed because disease remained controlled despite residual primary disease. Pathological examination revealed residual viable tumor (ypT2N2M0). Immunohistochemistry suggested differences in the immune microenvironment between the primary tumor and liver metastasis. The patient remained recurrence-free 15 months after surgery. CONCLUSIONS: This rare case highlights the heterogeneous response between the primary tumor and liver metastasis after GCD therapy and demonstrates the potential role of conversion surgery in selected patients with metastatic DCC. It provides important insight into treatment decision-making in this clinical setting.