[A Case of Hilar Cholangiocarcinoma Arising during Long-Term Follow-Up of Hepatolithiasis].

A 91-year-old man had a history of cholecystectomy and choledochostomy for cholecystolithiasis and choledocholithiasis. Eleven years earlier, intrahepatic stones were found in the posterior bile duct, and he did not wish to undergo treatment. Over time, worsening of the intrahepatic stones and dilation of the intrahepatic bile duct were observed. At 91 years old, enhanced abdominal CT revealed wall thickening of the hilar bile duct, and MRCP showed stenosis of the hilar bile duct. Endoscopic retrograde cholangiography showed no contrast in the right intrahepatic bile duct and marked dilation of the left intrahepatic bile duct. Brush cytology confirmed adenocarcinoma, leading to a diagnosis of hilar cholangiocarcinoma. He underwent open right and caudal lobectomy with biliary reconstruction. Histopathological examination revealed a hilar cholangiocarcinoma, T3N1M0, Stage Ⅲc, mainly located at the confluence of the right and left hepatic ducts. This case suggests a potential association between hepatolithiasis and hilar cholangiocarcinoma, emphasizing the importance of regular imaging examinations for timely surgical resection. Early intervention, including liver resection, is recommended for the management of hepatolithiasis.

[Long-Term Complete Response by CapeOX plus Nivolumab Chemotherapy for Postoperative Recurrence of Gastric Cancer-A Case Report].

A 73-year-old man underwent upper gastrointestinal endoscopy during a medical check-up that revealed a Type 2 lesion in the anterior wall of the gastric body. The biopsy confirmed tub2. A contrast-enhanced CT scan revealed focal wall thickening and lymphadenopathy in the gastric body. The patient was diagnosed with gastric cancer(M, ante, Type 2, T4aN1M0, Stage ⅢA). Laparotomy total gastrectomy D2 dissection and Roux-en-Y reconstruction were performed. Pathological results were tub1, int, INF b, ly0, v1, pT4aN0M0, pStage ⅡB. S-1(100 mg/day)was started as adjuvant chemotherapy but discontinued after 3 courses due to anorexia(Grade 2). Multiple pulmonary metastases(both lungs, 5)were confirmed by CT examination 9 months after the operation. A diagnosis of gastric cancer recurrence was made, and CapeOX plus nivolumab was started as first-line therapy. After 2 courses, lung metastases tended to shrink. The lesion developed a complete response(CR)after 3 months. After that, CapeOX plus nivolumab was continued, but peripheral neuropathy(Grade 2)was observed in the 15th course. With continued capecitabine monotherapy and nivolumab(impaired liver function [Grade 3]for irAE), despite the maintenance of CR, hepatic function increased repeatedly(Grade 3)and led to the discontinuation of chemotherapy upon patient's request. Currently, CR has been maintained for 5 years and 6 months after recurrence.

[A Case of Conversion Surgery for Stage â £ ATP-Producing Gastric Cancer with Distant Metastasis].

We report a case in which a patient with advanced gastric cancer with liver metastasis and bulky N showed marked tumor shrinkage with chemotherapy, and underwent conversion surgery. A 77-year-old male. Patient was referred to our department because of advanced gastric cancer. Upper gastrointestinal endoscopy revealed type 2 advanced cancer in the posterior wall of the gastric antrum. Abdominal CT showed thickening of the gastric wall in the same region and bulky lymph node enlargement and para-aortic lymphadenopathy behind the stomach. Staging laparoscopy showed the primary tumor and bulky lymph nodes forming a single mass, invading the pancreas, jejunum, and mesentery, and a solitary mass in the hepatic S3. Biopsy pathology revealed adenocarcinoma. We diagnosed the advanced gastric cancer cT4b(pancreas, jejunum), N2M1 (LYM, HEP), P0CY0, Stage ⅣB. After 2 courses of systemic chemotherapy FOLFOX/nivolumab, total gastrectomy, D2 node dissection, splenectomy pancreas tail resection, cholecystectomy, hepatic resection, partial transverse colon resection, partial jejunum resection, Roux-en-Y reconstruction. R0 resection was performed. The operative time was 620 minutes and blood loss was 1,025 mL. Pathologically, the patient was diagnosed with hepatoid adenocarcinoma, ypT4bN1M1(LYM, HEP), ypStage Ⅳ. The pathological efficacy evaluation was Grade 1a in the primary tumor. The patient has been recurrence-free for 9 months since the initial diagnosis.

Minimally invasive liver resection for cholangiolocellular carcinoma: A single-institution experience.

INTRODUCTION: Cholangiolocellular carcinoma (CoCC) resembles cholangiocellular carcinoma (CCC) and presents a variety of imaging findings; thus, preoperative diagnosis is often difficult. METHODS: We retrospectively studied patients who were diagnosed with CoCC at the Kansai Rosai Hospital from 2006 to 2021 and treated by laparoscopic liver resection (LLR) or open liver resection (OLR). RESULT: Among 918 liver resections, 15 patients were diagnosed with CoCC: 11 underwent LLR and 4 OLR. For LLR and OLR, respectively, patient age was 69.9 ± 6.8 and 72.8 ± 10.6, sex was M/F: 10/1 and 2/2, Child-Pugh was A/B/C: 10/1/0 and 4/0/0, liver damage was A/B/C: 8/3/0 and 4/0/0, preoperative diagnosis was CoCC/CCC/HCC: 1/2/8 and 2/2/0, pathological stage of Union for International Cancer Control (UICC) was IA/IB/II/IIIA/IIIB/IV: 8/0/2/1/0/0 and 0/0/3/0/1/0 (p = .0312), and extent of liver resection was Hr0/HrS/Hr1/Hr2/: 3/0/5/3 and 1/1/0/2. In LLR and OLR, respectively, operation time was 417.5 ± 191.0 and 407.5 ± 187.9 min, blood loss was 123.3 ± 217.4 and 1385.0 ± 1038.7 mL, and postoperative hospital stay was 12.2 ± 13.7 and 15.0 ± 6.6 days. For stages I and II/III, respectively, the 5-year disease-free survival rates were 100.0% and 34.3%, and the 5-year overall survival rates were 100.0% and 55.6%. For stage II/III LLR and OLR, respectively, the 3-year disease-free survival rates were 33.3% and 37.5% (p = .8418), and the 5-year overall survival rates were 66.7% and 50.0% (p = .8084). CONCLUSION: Although further studies are still needed to confirm, minimally invasive liver resection without lymph node dissection is one of a safe and effective approach to the management of CoCC.

Usefulness of blood flow evaluation by indocyanine green fluorescence in laparoscopic or robot-assisted surgery for colorectal cancer with persistent descending mesocolon.

A persistent descending mesocolon is defined as a congenital fixation anomaly caused by the defective membrane fusion of the descending colon and the lateral abdominal wall. Anatomically, in persistent descending mesocolon, the left colonic artery is often shortened, and joins the marginal artery soon after its bifurcation from the inferior mesenteric artery, while the colonic mesentery often adheres firmly to the mesentery of the small intestine. As a result of these characteristics, anatomical knowledge of the persistent descending mesocolon and preservation of bowel blood flow are important during surgery for left-sided colorectal cancer to avoid adverse events. Moreover, indocyanine green based blood flow assessment is useful for the detailed evaluation of bowel ischemia at the anastomotic site. Here we report the usefulness of blood flow evaluation using indocyanine green fluorescence in laparoscopic or robot-assisted surgery for three patients with colorectal cancer and persistent descending mesocolons.

[A Case of Inguinal Hernial Sac Metastasis of Cecal Cancer Resected with TAPP Approach].

Malignant tumor occurring in the inguinal region are relatively infrequent, and metastatic tumor is extremely rare. We report a case of inguinal hernial sac metastasis of cecal cancer resected with TAPP approach. The case is a 80's man. One year and 6 months after cecal cancer surgery, contrast-enhanced computer tomography(CT)examination revealed a solitary tumor in the right inguinal canal. We diagnosed inguinal hernia sac metastasis of cecal cancer and performed surgery. The mass in the hernia sac was resected with the TAPP approach. Histopathological findings were consistent with peritoneal metastasis directly to the inguinal hernia sac. The patient has been alive without 2 years after metastasectomy. It is necessary to treat patients with a history of malignant disease with keeping the possibility of inguinal hernia sac metastasis in mind.

[A Case of Sister Mary Joseph's Nodule after Radiation Therapy for Cervical Cancer].

An umbilical metastasis from an internal malignancy is called Sister Mary Joseph's nodule(SMJN)and has a poor prognosis. Herein, we report a case of umbilical metastasis of cervical cancer. A woman in her eighties underwent radiation therapy for cervical cancer(cT3bN0M0, cStage ⅢB). Primary tumor shrank after treatment, suggesting that radiation therapy induced complete response. Two years and 9 months after treatment, the patient presented with umbilical pain. A CT scan showed an umbilical mass near the umbilical hernia. PET-CT demonstrated high accumulation of FDG at the mass, which led to suspicion of umbilical metastasis(SMJN). Although she underwent radical surgery, she died from cancer 8 months after surgery.

[A Case of Conversion Surgery after Long-Term Chemotherapy for Pancreatic Cancer with Peritoneal Metastasis].

A 66-year-old woman was referred to the gastroenterology division of our hospital due to elevation of serum CEA level. Contrast-enhanced CT showed a hypovascular tumor at the body of pancreas. She was diagnosed with pancreatic cancer by EUS-FNA. By laparotomy, we found white nodules on mesentery and abdominal wall, which were diagnosed as peritoneal metastasis. After systemic chemotherapy with 9 courses of gemcitabine(GEM)plus nab-paclitaxel(PTX)and 30 courses of mFOLFIRINOX, the tumor had shrunk and serum CA19-9 level were remarkably decreased. Distal pancreatectomy was performed as conversion surgery. Pathological analysis revealed no remnant cancer cells in the primary tumor or the lymph nodes, confirming a pCR. S-1 was started as adjuvant chemotherapy, and she remains alive without recurrence 8 months after surgery.

[The Investigation about Cases Performed Laparoscopic Pancreas-Sparing Duodenectomy in Our Hospital].

INTRODUCTION: There are few reports of surgery which preserve the function of pancreas for benign or low malignant tumors. While we have introduced laparoscopic pancreaticoduodenectomy (LPD), we have also performed laparoscopic pancreas-sparing duodenectomy (LPSD). In the present study, we investigated surgical techniques and results of LPSD. MATERIALS AND METHODS: Between October 2019 and January 2022, 3 patients were underwent LPSD. The procedure was performed after obtaining approval from the Ethics Review Committee of our hospital. RESULTS: Three patients conducted LPSD were all males with a median age of 74 years, and diagnoses were adenomas of duodenum in 2 cases and gastrointestinal stromal tumor of duodenum in 1 case. The median blood loss was small amount. The median operative time was 430 minutes, and the median postoperative hospital stay was 13 days. One of the cases was performed with conversion to HALS. In LPSD, an intraoperative ultrasonography and an intraoperative radiographic contrast study were performed to confirm that the ampulla of Vater was preserved. There were no postoperative complications. CONCLUSION: We experienced cases performed LPSD in our hospital. We need further research for feasibility and safety of the procedure.

[Robotic and Laparoscopic Pancreaticoduodenectomy for the Elderly Patients-A Single Institutional Experience].

INTRODUCTION: Laparoscopic pancreaticoduodenectomy(LPD)has been covered by insurance since 2016 in Japan. Advance LPD and robotic pancreaticoduodenectomy(RPD)has been also covered by insurance since 2020 in Japan. The aim of this study was to analyze the perioperative results and outcomes of RPD and LPD for the elderly patients and to compare to the non-elderly patients. PATIENTS AND METHOD: Between July 2020 and April 2023, 67 patients underwent RPD and between May 2012 and February 2021, 63 patients underwent LPD at Kansai Rosai Hospital. Sixty-seven RPD and 62 LPD patients without extended resection were divided into 2 groups those who were over 75 years old(R/LPD E)(n=55)and under 74 years old(R/LPD non-E)(n=74). Control patients who received open pancreaticoduodenectomy(OPD)without extended resection between April 2010 and April 2023 were also divided into 2 groups those who were over 75 years old(OPD E)(n =60)and under 74 years old(OPD non-E)(n=78). The patient age was 79.0 and 60.5 years, the male to female ratio was 35/20 and 45/29, disease ratio(invasive ductal carcinoma or not)was 7/48 and 9/65 in R/LPD E and R/LPD non-E groups, respectively. The patient age was 79.0 and 79.5 years, the male to female ratio was 35/20 and 31/29, disease ratio (invasive ductal carcinoma or not)was 7/48 and 30/30(p<0.0001)in R/LPD E and OPD E groups, respectively. This study was approved by the Human Ethics Review Committee of Kansai Rosai Hospital(Certificate Number: 2001019). RESULTS: The average operation time was 644.6 and 675.2 minutes, an estimated blood loss was 220.8 and 134.4 g, postoperative pancreatic fistula(ISGPS 2016, [-]/BL/Grade B/C)was 24/18/13/0 and 28/25/21/0, delayed gastric emptying(ISGPS 2007, [-]/Grade A/B/C)was 48/0/4/3 and 61/2/6/5 and postoperative hospital stay was 27.9 and 25.9 and in R/LPD E and R/LPD non-E groups, respectively. No significant differences were noted between the groups, However, postoperative complication over Ⅲa Clavien-Dindo classification was 8(15.7%)and 3(4.4%)cases(p=0.0319)in R/LPD E and R/ LPD non-E groups. The average operation time was 644.6 and 492.1 minutes(p<0.0001), an estimated blood loss was 220.8 and 534.8 g(p=0.0004), postoperative pancreatic fistula(ISGPS 2016, [-]/BL/Grade B/C)was 24/18/13/0 and 27/8/24/1(p=0.0442), postoperative hospital stay was 27.9 and 42.0(p=0.0490)in R/LPD E and OPD E groups, respectively. CONCLUSION: The R/LPD was undergone in safety, even for the over 75 years old patients.

[Robot Assisted Para-Aortic Lymphadenectomy in Gastric Cancer Surgery].

Para-aortic lymphadenectomy in gastric cancer surgery is a highly difficult surgical technique. In our hospital, we introduced robotic surgery in anticipation of the minimal invasiveness and advanced operability. We use a tunneling approach that progresses from the Treitz ligament to the peri-aorta. The transverse mesocolon is expanded with a tissue grasping clip, and the retroperitoneum is incised from the side of the Treitz ligament to approach the abdominal aorta and inferior vena cava. The No.16b1 and No.16a2 latero lymph nodes can be dissected with a good visual field. When it is judged that the visual field development of the No.16a2 inter-lymph nodes is poor, Kocher's operation is added. Since 2016, 18 patients have undergone para-aortic lymphadenectomy, 3 of whom underwent robotic surgery in our hospital. R0 resection was performed in all the cases, and 22.5 lymph nodes were dissected as No.16 lymph nodes(20.0 in all the cases included laparotomy). Although only a small number of patients were examined, robot-assisted para-aortic lymphadenectomy was considered safe.

[A Case of Small Intestinal GIST Associated with Neurofibromatosis Type 1].

A 41-year-old male, with a history of neurofibromatosis type 1(NF1)was referred for further evaluation of positive fecal occult blood test. Abdominal contrast-enhanced CT incidentally showed a mass lesion with early darkening in the small intestine. It was suspected to be a small intestinal arteriovenous malformation, and surgery was performed. The tumor in the small intestine was resected under laparoscopic assistance. The histopathological diagnosis was gastrointestinal stromal tumors associated with NF1, which are usually located in the small intestine and relatively favorable prognosis.

[A Case of TMB-High Recurrent Peritoneal Seeding in Hilar Cholangiocarcinoma Treated with Pembrolizumab Therapy].

Tumor mutation burden(TMB)-High is known to potentially elicit a favorable response to immune checkpoint inhibitors. In this report, we present a case of recurrent hilar cholangiocarcinoma with TMB-High, in which we performed comprehensive treatment including immune checkpoint inhibitor pembrolizumab. The patient was a 58-year-old male diagnosed with hilar cholangiocarcinoma who underwent extended right hepatectomy, caudate lobe resection, bile duct excision, and bile duct reconstruction. Postoperatively, peritoneal seeding recurrence and liver metastasis were observed, indicating TMB-High. Therefore, pembrolizumab therapy was administered. The tumor marker CA19-9 significantly decreased, and the peritoneal seeding and liver metastatic lesions disappeared on imaging. In this case, we experienced the use of pembrolizumab monotherapy for TMB-High recurrent bile duct cancer with early postoperative peritoneal seeding recurrence. Further accumulation of cases is needed, but pembrolizumab monotherapy holds promise as a treatment option for TMB-High bile duct cancer at the hepatic hilum.

[Clinicopathological Characteristics of Early-Onset Colorectal Cancer(EOCRC)Cases in Our Hospital].

BACKGROUND: In recent years, the number of colorectal cancer in Europe and the U. S. has been decreasing, but there are increasing reports on the trend of early-onset colorectal cancer(EOCRC), which is a rare population with no established knowledge on its characteristics. SUBJECTS AND METHODS: Of 3,501 colorectal cancer cases treated at our hospital between April 2011 and December 2021, those aged 39 years and younger were included. RESULTS: There were 32 EOCRC cases, 11 males/21 females. The histological type was tub in 31 cases and por in 1 case. Postoperative adjuvant chemotherapy was administered in 14 patients, and 12 completed the scheduled course. Twenty nine patients underwent R0 resection, of which 6 patients had recurrence and 5 patients died of primary disease. In summary, although EOCRC patients were in good general condition and had a high completion rate of adjuvant chemotherapy, the relapse rate was high, suggesting the need for aggressive adjuvant chemotherapy and careful postoperative surveillance.

[Laparoscopic Liver Resection for the Elderly Hepatocellular Carcinoma Patients-A Single Institutional Experience].

INTRODUCTION: Laparoscopic liver resection(LLR)has been reported as a safe, minimally invasive, and effective approach to the management of liver tumor. The aim of this study was to analyze the perioperative results and outcomes of LLR for the elderly hepatocellular carcinoma(HCC)patients and to compare to the non-elderly HCC patients. PATIENTS AND METHOD: Between May 2010 and November 2021, 725 patients(HCC 407, CRC Mets 171, others 147)patients underwent LLR at Kansai Rosai Hospital. 407 patients who underwent LLR for HCC were divided into 2 groups those who were over 80 years old(n=67)and under 79 years old(n=340). The patient age was 82.7 and 68.8 years, while the male to female ratio was 41/26 and 238/102 in the elderly and non-elderly groups, respectively. According to the liver cancer study group of Japan, the pathological Stage 0/Ⅰ/Ⅱ/Ⅲ/Ⅳ was 23/34/8/2 and 117/146/57/20 patients(p=0.1086)in the elderly and non- elderly groups, respectively. This study was approved by the Human Ethics Review Committee of Kansai Rosai Hospital(Certificate Number: 2101006). RESULTS: The elderly group had an average operation time of 316.1 minutes, an estimated blood loss of 277.3 g, and a hospital stay of 14.3 days. The non-elderly group had an average operation time of 347.2 minutes, an estimated blood loss of 233.7 g, and a hospital stay of 12.9 days. No significant differences were noted between the elderly patients and the non-elderly patients with respect to the rate of procedure, operation time, intraoperative blood loss, hospital stay, morbidity, and postoperative laboratory data. CONCLUSION: The LLR was undergone in safety, even for the over 80 years old patients. The results of LLR for HCC over 80 years old were comparable both in short-term results with under 79 years old group. It was considered that the minimally invasiveness of LLR allows comparable surgical treatment for the elderly with non-eldery.

[Laparoscopic Liver Resection for Liver Metastasis of Colorectal Cancer].

The laparoscopic surgery is less invasive and better cosmetic. The laparoscopic liver resection(LLR)has been accepted for the insurance in April 2010, and increasingly performed in many hospitals, and also expected in metastasis of colorectal cancer. We retrospectively examined the results of LLR for liver metastasis of colorectal cancer. From June 2010 to July 2021, 174 cases of LLR for liver metastasis of colorectal cancer were performed in our hospital. The operation time was 384.5 minutes, the blood loss was small amount, and the postoperative hospital stay was 8 days. The complications were post-bleeding in 1 case, bile leakage in 7 cases, SSI in 16 cases, and no surgery-related deaths were observed. The 3-year disease-free survival rate was 22.8%, and the 5-year overall survival rate was 53.3%. In the comparison between single LLR and multiple LLR, the operation time and the blood loss increased, but there was no significant difference in the length of postoperative hospital stay. In initial LLR and repeat LLR, there were no significant differences in the operation time, blood loss, and postoperative hospital stay. In the primary lesion and simultaneous LLR and heterochronous LLR, the operation time and blood loss were not significantly different, but postoperative intra-abdominal abscess and SSI were more happened, and the postoperative hospital stay was significantly extended. LLR for liver metastasis of colorectal cancer can be safely performed at multiple sites or multiple times, and good treatment results have been obtained, so it was considered to be an effective treatment method.

[Conversion Surgery for Stage â £ Gastric Cancer with Liver Metastases after Second-Line Chemotherapy(Ramucirumab/Paclitaxel)-A Case Report].

A 78-year-old man was diagnosed with a liver tumor on follow-up CT after thoracic aortic aneurysm surgery. Esophagogastroduodenoscopy revealed a type 2 tumor in the gastric antrum, a biopsy showed poorly differentiated adenocarcinoma, and CT revealed multiple liver metastases, resulting in a diagnosis of clinical Stage ⅣB(cT4aN0M1[HEP]). S-1/oxaliplatin (SOX)chemotherapy was started. However, after 9 courses of chemotherapy, the primary tumor continued to increase in size. Ramucirumab/paclitaxel(RAM/PTX)was started; after 3 courses, CT revealed shrinkage of the primary tumor and disappearance of multiple liver metastases. PET-CT showed no abnormal FDG accumulation in the stomach, surrounding lymph nodes, and liver. Therefore, the patient was considered to have a PR in efficacy, and a decision to perform conversion surgery was made based on the assumption that curative resection was possible. The patient underwent laparoscopic distal gastrectomy D2 lymph node dissection and Billroth Ⅰ reconstruction. The pathological result was M, Ant, type 2, por, ypT2N0M0, ypStage ⅠB, while the histological effect of the chemotherapy was Grade 0. The patient was treated with paclitaxel as adjuvant chemotherapy, which was discontinued 1 year after surgery owing to no recurrence. No recurrence has been noted during 2 years of follow-up.

[Techniques and Short-Term Outcomes of Robotic Pancreaticoduodenectomy].

INTRODUCTION: Laparoscopic pancreaticoduodenectomy(LPD)has been covered by insurance since 2016 in Japan. Advance LPD and robotic pancreaticoduodenectomy(RPD)has been also covered by insurance since 2020 in Japan. We report our technique and the short-term outcome of RPD performed in our institution. SURGICAL PROCEDURES: As a first step, the resection phase was performed laparoscopically. Pancreato-jejunostomy and choledocho-jejunostomy were performed robotically (hybrid-RPD). As a second step, Kocher maneuver and jejunal transection were performed laparoscopically. Other procedures were performed robotically(modified-RPD). As a final step, all procedures were performed robotically(pure-RPD). SURGICAL TECHNIQUES: RPD is performed in reverse Trendelenburg supine position. An extended Kocher maneuver is performed. The common bile duct is then identified and transected after proximal aspect is secured with a surgical bulldog clamp. IPDA is divided by using an energy device after clip placement. The pancreatic neck is then divided with the use of scissors. Pancreato-jejunostomy was performed by modified Blumgart and pancreatic duct to jejunal mucosa method. Choledocho- jejunostomy was performed with continuous and interrupted suturing. PATIENTS AND METHOD: Between 2020 and 2022, 45 patients underwent RPD at our institution. Cases were divided into hybrid-RPD(n=20), modified-RPD(n=9) and pure-RPD(n=16). RESULTS: No significant differences were noted between hybrid-RPD, modified-RPD and pure-RPD groups with respect to patient age(73.6, 68.7, 70.6 years old), gender(male/female 15/5, 6/3, 8/8), respectively. The operation time was longer(667, 770, 746 minutes)and the resection time was longer(286, 399, 380 minutes)in modified- RPD and pure-RPD than hybrid-RPD group. In the pure-RPD group, the resection time was decreasing(y=-12.0×+ 481.5)as a learning curve. No significant differences were noted between hybrid-RPD, modified-RPD and pure-RPD groups with respect to reconstruction time(388, 371, 367 minutes)and the estimated blood(261, 199, 293 mL), respectively. All postoperative pancreatic fistula was under Grade B. CONCLUSION: Although further studies are still needed to confirm the benefit of RPD, RPD is safe, minimally invasive, and effective approach to the management of pancreatic tumor.

A Four-Dimensional Organoid System to Visualize Cancer Cell Vascular Invasion.

Vascular invasion of cancer is a critical step in cancer progression, but no drug has been developed to inhibit vascular invasion. To achieve the eradication of cancer metastasis, elucidation of the mechanism for vascular invasion and the development of innovative treatment methods are required. Here, a simple and reproducible vascular invasion model is established using a vascular organoid culture in a fibrin gel with collagen microfibers. Using this model, it was possible to observe and evaluate the cell dynamics and histological positional relationship of invasive cancer cells in four dimensions. Cancer-derived exosomes promoted the vascular invasion of cancer cells and loosened tight junctions in the vascular endothelium. As a new evaluation method, research using this vascular invasion mimic model will be advanced, and applications to the evaluation of the vascular invasion suppression effect of a drug are expected.

Convolutional Neural Network Can Recognize Drug Resistance of Single Cancer Cells.

It is known that single or isolated tumor cells enter cancer patients' circulatory systems. These circulating tumor cells (CTCs) are thought to be an effective tool for diagnosing cancer malignancy. However, handling CTC samples and evaluating CTC sequence analysis results are challenging. Recently, the convolutional neural network (CNN) model, a type of deep learning model, has been increasingly adopted for medical image analyses. However, it is controversial whether cell characteristics can be identified at the single-cell level by using machine learning methods. This study intends to verify whether an AI system could classify the sensitivity of anticancer drugs, based on cell morphology during culture. We constructed a CNN based on the VGG16 model that could predict the efficiency of antitumor drugs at the single-cell level. The machine learning revealed that our model could identify the effects of antitumor drugs with ~0.80 accuracies. Our results show that, in the future, realizing precision medicine to identify effective antitumor drugs for individual patients may be possible by extracting CTCs from blood and performing classification by using an AI system.