Long-term survival after hepatectomy for metachronous liver metastasis of pancreatic ductal adenocarcinoma: a case report

Background: Pancreatic ductal adenocarcinoma (PDAC) is among the most aggressive malignancies. The prognosis for recurrence after surgery is extremely unfavorable, and liver metastasis of PDAC confers poor prognosis despite resection. Case presentation: A 69-year-old man was admitted to our hospital for further examination and treatment, including surgery for a pancreatic tumor. On close inspection, he was suspected to have pancreatic head cancer without enlarged lymph nodes or distant metastasis, and pancreatoduodenectomy with D2 lymph node dissection was performed. A postoperative pathological examination revealed well-differentiated invasive ductal adenocarcinoma with lymph node metastasis (stage IIB; pT2N1M0). Postoperatively, he received adjuvant chemotherapy containing gemcitabine for 1 year. Eight years after the radical surgery, his serum carbohydrate antigen 19-9 level was elevated, and computed tomography (CT) and magnetic resonance imaging revealed a well-circumscribed 10-mm mass in liver segment 5. Positron emission tomography/CT also revealed high fluorine-18-fluorodeoxyglucose uptake only in this hepatic tumor. Accordingly, the patient was diagnosed with a solitary liver metastasis of PDAC. As the liver metastasis was isolated and identified long after the initial surgery, we decided to resect it using laparoscopic partial hepatectomy of segment 5. Histopathological examination confirmed liver metastasis of PDAC and the patient received adjuvant chemotherapy containing S-1. No evidence of recurrence has been seen for 11 years since the pancreatoduodenectomy and 3 years since the hepatic resection. Conclusions: Cases of metachronous liver metastasis of PDAC after radical surgery, in which patients exhibit long-term survival without recurrence after hepatectomy, are extremely rare. Hepatectomy may confer long-term survival, and the time to postoperative recurrence and the number of liver metastases may be useful criteria for deciding whether to perform hepatic resection.