A 61-year-old man with no significant medical history presented to our hospital with back pain that started a week prior to his visit. Physiological and laboratory examinations were unremarkable except for elevated serum carbohydrate antigen 19-9 (CA19-9) and s-pancreas-1 antigen (SPan-1) levels (CA19-9, 141 U/mL; SPan-1, 110.8 U/mL). Contrast-enhanced abdominal computed tomography (CT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) revealed the presence of a 35-mm hypovascular tumor in the head and body of the pancreas, with dilatation of the main pancreatic duct and atrophy of the pancreatic tail. The tumor was observed to be in contact with the entire length of the common hepatic artery (CHA), the proximal portion of the proper hepatic artery (PHA), the gastroduodenal artery (GDA), and the root of the splenic artery (SPA) (Fig. 1). Distant metastasis was not observed. Based on these findings, the patient was diagnosed with unresectable LAPC.
We performed systemic chemotherapy consisting of gemcitabine plus nab-paclitaxel (GnP) (gemcitabine 1000 mg/m2 and nab-paclitaxel 125 mg/m2 on days 1, 8, and 15 every 4 weeks). After two treatment cycles, the tumor decreased in size from 35 to 20 mm. While CT revealed that the tumor was still in contact with the CHA, PHA, and SPA, contrast-enhanced MRI revealed a gap between the tumor and these arteries (Fig. 2). No distant metastasis was observed. The CA19-9 and SPan-1 levels decreased and then returned to their normal range. Based on these findings, we decided to perform conversion surgery. Next, the patient underwent another two cycles (a total of four cycles) of GnP therapy prior to surgery.
The CHA was invaded by the tumor over its entire length before chemotherapy; therefore, combined resection of the hepatic artery was considered more desirable for curability and safety. Furthermore, the patient had an aberrant A2 that had bifurcated from the left gastric artery. Therefore, we planned PD with hepatic arterial resection without reconstruction. We opted to perform preoperative hepatic arterial embolization to prevent postsurgical ischemic complications. Angiography after CHA and PHA embolization immediately confirmed collateral arterial flow to the whole liver fed by the aberrant A2 and right inferior phrenic artery (Rt. IPA) (Fig. 3). Moreover, dynamic CT conducted after embolization confirmed uniform intrahepatic arterial blood flow to the whole liver.
Nineteen days after embolization, we performed PD, PV resection with reconstruction, hepatic arterial resection without reconstruction (to preserve the aberrant A2), and D2 lymphadenectomy. The tissues around the CHA and the root of the SPA that were invaded before chemotherapy became extremely stiff; however, those around the embolized PHA were not very stiff. Therefore, the CHA was transected at its root. The distal part of the hepatic artery was transected at the root of the right, middle, and left hepatic arteries. The bile duct was transected below the bifurcation. The PV, superior mesenteric vein (SMV), and splenic vein were transected (4 cm in length), and end-to-end anastomosis of the PV and SMV was conducted with mobilization of the right colon and ileum (Fig. 4). At the end of the surgery, intraoperative Doppler ultrasonography revealed good arterial and portal flow to the whole liver. The total operation time was 947 min, and the total blood loss was 2972 mL.
Histopathological examination revealed an invasive ductal carcinoma, tub2 > por, Pbh, TS2 (40 mm), infiltrative type, ypT3, int, INFb, ly1, v1, ne0, mpd0, ypCH0, ypDU0, ypS0, ypRP0, ypPV1 (PVsp), ypA0, ypPL0, ypOO0, ypPCM0, ypBCM0, ypDPM0, ypN1a (3/11), ypM0, ypStage IIB according to the Japan Pancreatic Society classification, 7th edition. According to the UICC TNM classification (8th edition), the tumor was defined as T2N1M0, stage IIB. No carcinoma cells were detected in the surgical margin (R0). Histologically, this tumor was categorized as Evans grade I (Fig. 5).
Although liver enzymes levels were slightly increased and CT performed on the 7th day after surgery revealed the presence of a small ischemic area in liver segment 8, no liver abscess developed. The postoperative course was uneventful, and the patient was discharged 17 days after the surgery. He received S-1 (60 mg, orally administered twice a day for 28 days followed by a 14 day rest, every 6 weeks [one cycle]) as adjuvant chemotherapy for a year and is currently alive with no evidence of recurrence and without any ischemic liver events and cholangitis within the last 4 years since his surgery.