A 73-year-old man presented to his local hospital with a 3-month history of inappetence and body weight loss. Abdominal ultrasonography revealed pancreatic body cancer, and he was referred to our hospital. He had type 2 diabetes mellitus and a history of appendectomy performed when he was 20 years of age. His family history included that his uncle has a history of gastric cancer. Laboratory data revealed a high level of hemoglobin A1c (8.1%), but tumor markers, including carcinoembryonic antigen (2.1 ng/mL), cancer antigen-19-9 (15.4 U/mL), Dupan-2 (29 U/mL), and Span-1 (11.4 U/mL), were all within normal limits. Computed tomography (CT) findings revealed a 2.5-cm mass in the pancreatic body (Fig. 1a). The celiac artery (CA), common hepatic artery (CHA), and splenic artery (SA) showed encasement by direct tumor invasion (Fig. 2a). There was no encasement of the superior mesenteric artery (SMA), but abutment of over 180° with the main tumor was seen (Fig. 2d). Magnetic resonance cholangiopancreatography revealed stenosis of the main pancreatic ducts with upstream dilatation of the pancreatic duct. Endoscopic retrograde cholangiopancreatography imaging also demonstrated pancreatic duct strictures near the pancreatic body. Endoscopic ultrasonography-guided fine needle aspiration cytology was performed, and pathological findings revealed a pancreatic adenocarcinoma. Positron emission tomography (PET) findings did not show the possibility of distant metastasis, and the maximum standard uptake value of the main tumor was 2.5. Staging laparoscopy showed no findings of peritoneal and/or liver metastasis. Additionally, washing cytology did not show malignancy. From these findings, we diagnosed the patient with unresectable locally advanced pancreatic cancer (UR LAPC).
Based on these findings, S-1 with radiation therapy was performed. Five days of S-1 intake (80 mg/m2/day) with radiation therapy (2 Gy/day) was performed per week. This treatment continued for 5 weeks, and the total radiation amount was 50 Gy. During this treatment, the patient experienced no significant adverse effects. After chemoradiation, CT findings showed that the encasement of the CA, CHA, and SA was released, but abutment to the SMA was still detected (Figs. 1a and 2b, e), so he was diagnosed as still having LAPC. Therefore, chemotherapy with gemcitabine and nab-paclitaxel followed.
At first, the standard regimen (i.e., days 1, 8, and 15: injection of gemcitabine (1000 mg/m2) and nab-paclitaxel (125 mg/m2) every 4 weeks) was proposed. However, because grade 3 thrombocytopenia was observed, biweekly chemotherapy was performed 12 times, and other side effects were not observed. After the treatments, the tumor size decreased to 1.2 cm (Fig. 1c), but abutment to the CA, CHA, SA, and SMA was still detected (Fig. 2c, f). PET findings did not show the possibility of distant metastasis, and the maximum standard uptake value for the main tumor was 2.4. Tumor markers, including carcinoembryonic antigen (2.9 ng/mL), cancer antigen-19-9 (12.4 U/mL), Dupan-2 (25.0 U/mL), and Span-1 (11.3 U/mL) were still all within normal limits.
We initially proposed embolization of the CHA and the left gastric artery before surgical treatment. However, the CHA was too short to be coiled safely and had a risk of embolization for the proper hepatic artery. Therefore, we only embolized the left gastric artery, expecting increased blood perfusion from the right gastric artery, and right gastroepiploic artery to avoid acute ischemic disease of the stomach after celiac axis resection. Six days after blocking the left gastric artery, surgical treatment was performed.
Intraoperative findings showed neither peritoneal nor liver metastasis. Intraoperative washing cytology revealed no findings of malignancy. A 2.0-cm tumor existed at the pancreatic body. It had invaded to the splenic vein, but far from the portal vein. Though abutment to SMA was still detected around the SMA by CT findings, intraoperative findings showed fibrous changes around the right half of the SMA and it could be easily separated from SMA. From these findings, we think that two thirds resection of the nerve plexus including fibrous change around the SMA was enough to achieve R0 resection. Based on these findings, we performed distal pancreatectomy with celiac axis resection with two thirds of the nerve plexus resection around the SMA (Fig. 3a, b). The total operation time was 438 min, and blood loss was 1239 mL.
Histopathological findings showed that a 0.8 × 0.5 cm, moderately differentiated tubular adenocarcinoma with marked degeneration, was present at the pancreatic body; 50–60% of the tumor was changed to fibrous tissue, defined as grade IIb in the Evans classification (Fig. 3c, d). The UICC TNM classification (7th edition) was defined as T1N0M0, stage IA. Including the nerve plexus around the SMA, there were no residual cancer cells in the dissected margin and/or the pancreatic resection margin. Therefore, we achieved R0 resection.
After surgical treatment, there were grade B complications of the pancreatic fistula, but they were controlled by percutaneous drainage not under general anesthesia (Clavien-Dindo IIIa). The patient was discharged from the hospital 52 days after surgical treatment. He has now been treated with S-1 as adjuvant chemotherapy and has done well without recurrence for more than 12 months from the initial treatment.