Abstract
BACKGROUND: The incidence of brain metastasis of pancreatic cancer has been reported to be approximately 0.3%. The blood-brain barrier of the central nervous system restricts the transfer of substances, including chemotherapeutic agents, from the bloodstream. It is hypothesized that brain metastasis may occur despite successful chemotherapy for the primary tumor. Herein, we report a case of brain metastases of pancreatic cancer that occurred after chemotherapy and discuss relevant literature. CASE PRESENTATION: A 64-year-old man underwent distal pancreatectomy with D2 lymph node dissection for resectable pancreatic tail cancer. Invasive ductal carcinoma of pancreas, pT3N2M0 pStageIII (TNM Classification of Malignant Tumors, UICC 8th edition) was diagnosed. S-1 adjuvant chemotherapy was initiated. Three months postoperatively, CA19-9 had increased to 619 U/mL. Additionally, contrast-enhanced computed tomography (CT) and fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT revealed local recurrence in the para-aortic lymph nodes. Chemotherapy was revised to a combined regimen of gemcitabine and nab-paclitaxel. After 4 cycles, tumor markers were normalized. After 5 cycles, recurrence could not be identified on contrast-enhanced CT; therefore, the patient was adjudged to be in complete remission. However, after 29 cycles of chemotherapy, the patient had symptoms of raised intracranial pressure. Magnetic resonance imaging showed two metastatic lesions of 20 mm and 32 mm in the left frontal lobe and cerebellum, respectively. Quasi-emergency resection of the metastatic brain tumors was performed. Pathological examination revealed that the resected specimens originated from primary pancreatic cancer. The patient was discharged on postoperative day 12, without any complications. Postoperatively, a total of 53 Gy of local brain radiation therapy was added. On postoperative day 30, blood carcinoembryonic antigen level had decreased to 5.4 ng/dl and all other tumor markers were negative. Additionally, tumor markers of the cerebrospinal fluid were markedly reduced and the cytology was negative for tumor cells. These results suggested complete resection of the metastatic brain tumors. CONCLUSIONS: Aggressive resection and salvage stereotactic radiotherapy for metastatic brain tumors may lead to complete cure and a good long-term prognosis.