Three-dimensional analysis of perineural invasion in extrahepatic cholangiocarcinoma using tissue clearing.

Perineural invasion (PNI) is a characteristic invasion pattern of distal cholangiocarcinoma (DCC). Conventional histopathologic examination is a challenging approach to analyze the spatial relationship between cancer and neural tissue in full-thickness bile duct specimens. Therefore, we used a tissue clearing method to examine PNI in DCC with three-dimensional (3D) structural analysis. The immunolabeling-enabled 3D imaging of solvent-cleared organs method was performed to examine 20 DCC specimens from five patients and 8 non-neoplastic bile duct specimens from two controls. The bile duct epithelium and neural tissue were labeled with CK19 and S100 antibodies, respectively. Two-dimensional hematoxylin/eosin staining revealed only PNI around thick nerve fibers in the deep layer of the bile duct, whereas PNI was not identified in the superficial layer. 3D analysis revealed that the parts of DCC closer to the mucosa exhibited more nerves than the normal bile duct. The nerve fibers were continuously branched and connected with thick nerve fibers in the deep layer of the bile duct. DCC formed a tubular structure invading from the epithelium and extending around thin nerve fibers in the superficial layer. DCC exhibited continuous infiltration around the thick nerve fibers in the deep layer. This is the first study using a tissue clearing method to examine the PNI of DCC, providing new insights into the underlying mechanisms.

Use of time­density curves of dynamic contrast­enhanced computed tomography for determination of the histological therapeutic effects of neoadjuvant chemotherapy for pancreatic ductal adenocarcinoma.

The present study aimed to investigate the histological changes caused by neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC), and to demonstrate the use of time­density curves (TDCs) of dynamic contrast­enhanced computed tomography (CECT) for determination of the histological therapeutic effects of NAC for PDAC. A total of 96 patients with PDAC were examined; 46 underwent NAC (NAC group) and 50 did not undergo NAC (non­NAC group). Based on histological therapeutic effect and using the area of residual tumor (ART) grading system, the NAC group was divided into low­responders and high­responders. Histological analysis was used to evaluate the densities of cancer cells, cancer­associated fibroblasts (CAFs), microvessels and stromal collagen fibers in the NAC and non­NAC groups. Radiological analysis was used to evaluate the TDCs of three slopes of the NAC group, namely slopes between the non­contrast and arterial phases (δ1 and δ1'), between the arterial and portal phases (δ2 and δ2'), and between the portal and equilibrium phases (δ3 and δ3'). δ1­Î´3 were before NAC, whereas δ1'­Î´3' were after NAC. Changes in δ1, δ2 and δ3 before and after NAC were denoted as δδ1 (=δ1'­Î´1), δδ2 (=δ2'­Î´2) and δδ3 (=δ3'­Î´3). ART grading system, histological examination and radiological examination data were also statistically analyzed. Histological examination revealed a significant decrease in cancer cells and CAFs, and a significant increase in stromal collagen fibers due to NAC (P<0.01). Radiological examination revealed that δ1' was significantly higher than δ1 in low­responders (P<0.05), whereas δ2' was significantly lower than δ2 in high­responders (P<0.01). δδ2 was significantly lower and δδ3 was significantly higher in high­responders than in low­responders (P<0.01 and P<0.05, respectively). Receiver operating characteristic curve showed that δδ2 and δδ3 were effective indicators of the histological therapeutic effect of NAC. In conclusion, the TDC of dynamic CECT may be useful for determining the histological therapeutic effect of NAC for PDAC.

[Intrathoracic Migration of a Kirschner Wire Successfully Removed by Video-assisted Thoracic Surgery:Report of a Case].

A 40-year-old man who had been surgically treated for the fracture of the right humerus with two Kirschner wires (K-wires) complained of chest pain and difficulty in breathing at fourth day after surgery and visited our hospital. Chest radiography revealed dislocation of the K-wire and right pneumothorax. Video-assisted thoracic surgery( VATS) was performed immediately, and the K-wire was removed safely.

[Short-Term Results of Robot-Assisted Surgery in Patients Undergoing Neoadjuvant Chemotherapy for Rectal Cancer].

The advantages of robot-assisted surgery include: stable deployment of the robotic arm that enables excellent radical cure characteristics and preservation of function; the ability to perform precise surgery even in patients in whom performing laparoscopic surgery is difficult, such as those with pelvic or bulky tumors. However, there have been some reports on such issues as an increase in the incidence of postoperative complications and an increase in postoperative hospital stay in patients who underwent neoadjuvant chemotherapy(NAC); thus, we summarized and are reporting the short-term results of our experience in patients seen in our department to date. A total of 76 patients with rectal cancer who underwent robot-assisted surgery, and short-term postoperative results were compared between patients who underwent neoadjuvant chemotherapy (NAC group)and those who did not undergo neoadjuvant chemotherapy(non-NAC group). Of the 76 patients, 59 (77.6%)were male and 17(22.4%)were female, and 27(35.5%)in the NAC group. In the comparisons between the NAC and non-NAC groups, although the difference in operative time(523.5 vs 317.5 minutes, p<0.01)was significant, there were no significant differences in any of blood loss(59 vs 20g, p=0.22), postoperative hospital stay(14 vs 13 days: p=0.07), and onset of complications that were Clavien-Dindo Grade Ⅲa or higher(2 vs 1 patients, p=0.82). Robot- assisted surgery after NAC for rectal cancer was considered to be safe and very useful.

Short-term outcomes of robotic-assisted laparoscopic versus laparoscopic lateral lymph node dissection for advanced lower rectal cancer.

BACKGROUND: Therapeutic strategies to suppress local recurrence, including lateral lymph node metastasis, are important to improve the curability of rectal cancer. The aim of the present study was to clarify the advantages of robotic-assisted laparoscopic lateral lymph node dissection (RALLD), comparing its short-term outcomes with those of laparoscopic lateral lymph node dissection (LLLD). There are some retrospective reports comparing RALLD or LLLD and open lateral lymph node dissection (OLLD), but few reports comparing RALLD and LLND to each other. METHODS: From November 2014 to August 2020, we compared the short-term outcomes in 40 patients who underwent RALLD and 55 patients who underwent LLLD. RESULTS: The total operative time was significantly longer in the RALLD group than in the LLLD group (p < 0.001). However, lateral dissection time was not significantly different between the groups (p = 0.661). The postoperative hospital time was shorter in the RALLD group than in the LLLD group (p < 0.048). No significant differences were identified in the rates of postoperative bleeding, incisional surgical site infection (SSI), organ/space SSI, urinary disfunction, urinary infection, or small bowel obstruction between the groups. However, anastomotic leakage was significantly lower in the RALLD group than in the LLLD group (p = 0.031). CONCLUSIONS: The short-term outcomes of RALLD indicate it is feasible, and RALLD may be a useful modality for lower rectal cancer.

[Treatment for Laterally Invasive Rectal Cancer with Robot-Assisted Surgery after Preoperative Treatment].

The patient is a 40-year-old male. He was referred to our department because, after a thorough examination, he was diagnosed with rectal cancer. Preoperative imaging showed a tumor in the rectum at the level of the seminal vesicles, and left lateral invasion was suspected. In addition, lymph node metastases in the left lateral area were suspected. We performed a robot-assisted low anterior resection plus bilateral lateral dissection plus covering ileostomy for this patient after neoadjuvant chemotherapy. The operation time was 495 minutes, and the blood loss was 50 g. The histopathological diagnosis was pT3, N3(#263), M0, pStage Ⅲc, PM0, DM0, RM0, R0, Cur A. In Japan, robotic-assisted surgery for rectal cancer has been covered by insurance since April 2018, and in our department, robotic surgery is the first option for any stage or type of surgery for rectal cancer. We believe that the greatest advantages of robotic surgery for rectal cancer are in lateral dissection, ie, the better understanding of how blood vessels and nerves travel around the internal iliac vessels and the associated anatomy of pelvic organs that comes from reliable lateral dissection. We have experienced a case of safe robotic-assisted radical resection of laterally invasive rectal cancer, which is considered to be relatively difficult, and we hereby report the usefulness of the robotic-assisted modality.

[A Case of Pancreatotomy of the Pancreatic Tail with a Preserved Residual Stomach Using ICG Fluorescence Method for Pancreatic Cancer after Gastrectomy of the Pyloric Side].

A 53-year-old male had a history of gastrectomy of the pyloric side for gastric cancer and Billroth Ⅰ reconstruction done 20 years ago. The patient visited the gastrointestinal internal medical department of our hospital with abdominal pain as the chief complaint. Pancreatic cancer was diagnosed with the help of an abdominal CT, and he was then referred to our department. The preoperative disease stage was cT3, N0, M0, Stage ⅡA. As it was over 20 years since the previous surgery and the preoperative CT showed cardiac branches of the left inferior phrenic artery, we inferred that the residual stomach can be preserved. The blood flow was confirmed by the intraoperative ICG fluorescence method, and we then performed pancreatotomy of the pancreatic tail, preserving the stomach and a splenectomy. The pathologic findings were invasive ductal carcinoma, pT3, N1a, M0, Stage ⅡB, and R0. S-1 was administered orally as postoperative adjunctive chemotherapy. The postoperative course has been favorable without recurrence for 2 years. In case a pancreatotomy of the pancreatic tail is performed for cancer of the pancreatic body after gastrectomy of the pyloric side, it was considered that the intraoperative ICG fluorescence method was useful to confirm the blood flow of the residual stomach.