Preoperative risk factors for skeletal muscle mass loss in patients with biliary tract cancer.

BACKGROUND: Endoscopic retrograde cholangiography (ERC)-related procedures, usually performed before biliary tract cancer (BTC) surgery, are associated with increased risk for various complications, which can cause sarcopenia. No study has previously elucidated the relationship between preoperative ERC-related procedures and sarcopenia/skeletal muscle mass loss. METHODS: Patients with BTC who underwent radical surgical resection following ERC-related procedures were included. Skeletal muscle mass was evaluated using the psoas muscle mass index (PMI), which was determined using computed tomography images, and the change in PMI before the initial pre-ERC and surgery (ΔPMI) was calculated. Risk factors for advanced skeletal muscle mass loss, defined as a large ΔPMI, were evaluated. RESULTS: The study cohort included 90 patients with a median age of 72 (interquartile range, 65-75) years. The median PMI pre-ERC and surgery was 4.40 and 4.15 cm2/m2, respectively (p < .01). The median ΔPMI was -6.2% (interquartile range, -10.9% to 0.5%). By multivariate analysis, post-ERC pancreatitis and cholangitis before surgery were independent predictive factors for large PMI loss (odds ratio, 4.57 and 3.18, respectively; p = .03 and p = .02, respectively). CONCLUSIONS: Skeletal muscle mass decreases preoperatively in most patients with BTC undergoing ERC. Post-ERC pancreatitis and cholangitis before surgery were independent risk factors for large skeletal muscle mass loss.

Impact of Neutrophil Extracellular Traps Identified by Citrullinated Histone H3 Immunohistochemistry for Postoperative Prognosis in Patients with Extrahepatic Cholangiocarcinomas.

BACKGROUND: Neutrophil extracellular traps (NETs) are extracellular chromatin structures composed of cytoplasmic, granular, and nuclear components of neutrophils. Recently, NETs have received much attention for their role in tumor biology; however, their impact on the postoperative prognosis of patients with extrahepatic cholangiocarcinomas (EHCCs) remains unclear. The purpose of this study was to clarify the impact of NETs identified by immunohistochemical citrullinated histone H3 (Cit-H3) staining on postoperative overall survival (OS) in patients with perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC). METHODS: This study included 318 patients with EHCC (PHCC, n = 192; DCC, n = 126) who underwent surgical resection with curative intent. Neutrophils and NETs were identified by immunohistochemistry using antibodies against CD15 and Cit-H3, respectively. Based on the distribution of CD15 and Cit-H3 expression in the tumor bed, the patients were classified into four groups: one negative group and three subgroups of the positive group (diffuse, intermediate, and focal subgroups). RESULTS: No significant difference was found in the postoperative OS rate depending on the distribution of CD15 expression in patients with PHCC or DCC. However, the three subgroups with positive Cit-H3 expression had significantly poorer OS than the negative group for both PHCC and DCC. Moreover, positive Cit-H3 was an independent OS factor in the multivariable analyses of PHCC (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.11-2.59, P = 0.0115) and DCC (HR 2.03; 95% CI 1.21-3.42, P = 0.0057). CONCLUSIONS: The presence of NETs in the tumor microenvironment may have adverse prognostic effects in patients with EHCCs.

The Short- and Long-Term Surgical Results of Consecutive Hepatopancreaticoduodenectomy for Wide-Spread Biliary Malignancy.

BACKGROUND: Cancer-free resection (R0) is one of the most important factors for the long-term survival of biliary carcinoma. For some patients with widespread invasive cancer located between the hilar and intrapancreatic bile duct, hepatopancreaticoduodenectomy (HPD) is considered a radical surgery for R0 resection. However, HPD is associated with high morbidity and mortality rates. Furthermore, previous reports have not shown lymph node metastasis (LNM) status, such as the location or number, which could influence the prognosis after HPD. In this study, first, we explored the prognostic factors for survival, and second, we evaluated whether the LNM status (number and location of LNM) would influence the decision on surgical indications in patients with widely spread biliary malignancy. METHODS: We retrospectively reviewed the medical records of 54 patients who underwent HPD with hepatectomy in ≥2 liver sectors from January 2003 to December 2021 (HPD-G). We also evaluated 54 unresectable perihilar cholangiocarcinoma patients who underwent chemotherapy from January 2010 to December 2021 (CTx-G). RESULTS: R0 resection was performed in 48 patients (89%). The median survival time (MST) and 5-year overall survival rate of the HPD-G and CTx-G groups were 36.9 months and 31.1%, and 19.6 months and 0%, respectively. Univariate and multivariate analyses showed that pathological portal vein involvement was an independent prognostic factor for survival (MST: 18.9 months). Additionally, patients with peripancreatic LNM had worse prognoses (MST: 13.3 months) than CTx-G. CONCLUSIONS: Patients with peripancreatic LNM or PV invasion might be advised to be excluded from surgery-first indications for HPD.

Validation study for prognostic scoring system for perihilar cholangiocarcinoma surgery using preoperative factors.

PURPOSE: Recently, systemic inflammatory responses (SIR) have been shown to play a pivotal role in the development and progression of cancer. We previously reported that four factors, serum carcinoembryonic antigen (> 7 ng/dL), serum albumin (< 3.5 g/dL), C-reactive protein (> 0.5 mg/dL), and platelet-lymphocyte ratio (PLR; > 150), were independent prognostic factors after perihilar cholangiocarcinoma (PHCC) surgery. We also advocated a prognosis predictive preoperative prognostic score (PPS) using these four factors and showed that PPS could predict patients' prognosis on survival. This retrospective study sought to validate preoperatively available prognostic factors for survival after major hepatectomy as reported previously, including PPS for PHCC. METHODS: We retrospectively validated our PPS score and reported SIR scoring systems using the data of 125 consecutive patients who underwent PHCC surgery from January 2010 to November 2020. RESULTS: PPS was an independent preoperative prognostic factors for survival. The T and N categories were independent prognostic factors. Other SIR scores were not independent preoperative factors in the univariate analysis. Among SIR scores, only the PPS was found to be associated with OS and disease-free survival. The PPS was also associated with histopathological factors (T and N categories). CONCLUSION: PPS could be useful in predicting long-term survival after PHCC and may be a more useful scoring system than other SIR systems.

Surgical skills assessment of pancreaticojejunostomy using a simulator may predict patient outcomes: A multicenter prospective observational study.

BACKGROUND: Pancreatoduodenectomy, an advanced surgical procedure with a high complication rate, requires surgical skill in performing pancreaticojejunostomy, which correlates with operative outcomes. We aimed to analyze the correlation between pancreaticojejunostomy assessment conducted in a simulator environment and the operating room and patient clinical outcomes. METHODS: We recruited 30 surgeons (with different experience levels in pancreatoduodenectomy) from 11 institutes. Three trained blinded raters assessed the videos of the pancreaticojejunostomy procedure performed in the operating room using a simulator according to an objective structured assessment of technical skill and a newly developed pancreaticojejunostomy assessment scale. The correlations between the assessment score of the pancreaticojejunostomy performed in the operating room and using the simulator and between each assessment score and patient outcomes were calculated. The participants were also surveyed regarding various aspects of the simulator as a training tool. RESULTS: There was no correlation between the average score of the pancreaticojejunostomy performed in the operating room and that in the simulator environment (r = 0.047). Pancreaticojejunostomy scores using the simulator were significantly lower in patients with postoperative pancreatic fistula than in those without postoperative pancreatic fistula (P = .05). Multivariate analysis showed that pancreaticojejunostomy assessment scores were independent factors in postoperative pancreatic fistula (P = .09). The participants highly rated the simulator and considered that it had the potential to be used for training. CONCLUSION: There was no correlation between pancreaticojejunostomy surgical performance in the operating room and the simulation environment. Surgical skills evaluated in the simulation setting could predict patient surgical outcomes.

CCR7 Mediates Cell Invasion and Migration in Extrahepatic Cholangiocarcinoma by Inducing Epithelial-Mesenchymal Transition.

The epithelial-mesenchymal transition (EMT) contributes to the metastatic cascade in various tumors. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine (C-C motif) ligand 19 (CCL19), to promote EMT. However, the association between EMT and CCR7 in extrahepatic cholangiocarcinoma (EHCC) remains unknown. This study aimed to elucidate the prognostic impact of CCR7 expression and its association with clinicopathological features and EMT in EHCC. The association between CCR7 expression and clinicopathological features and EMT status was examined via the immunohistochemical staining of tumor sections from 181 patients with perihilar cholangiocarcinoma. This association was then investigated in TFK-1 and EGI-1 EHCC cell lines. High-grade CCR7 expression was significantly associated with a large number of tumor buds, low E-cadherin expression, and poor overall survival. TFK-1 showed CCR7 expression, and Western blotting revealed E-cadherin downregulation and vimentin upregulation in response to CCL19 treatment. The wound healing and Transwell invasion assays revealed that the activation of CCR7 by CCL19 enhanced the migration and invasion of TFK-1 cells, which were abrogated by a CCR7 antagonist. These results suggest that a high CCR7 expression is associated with an adverse postoperative prognosis via EMT induction and that CCR7 may be a potential target for adjuvant therapy in EHCC.

Identification of antibody against wingless­type MMTV integration site family member 7B as a biliary cancer tumor marker.

Biliary cancer has a poor prognosis due to a lack of specific biomarkers and difficulty in diagnosis. The present study aimed to identify serum tumor markers for the diagnosis of biliary cancer via serological identification of antigens by recombinant cDNA expression cloning. Wingless­type MMTV integration site family, member 7 (WNT7B) was identified as a target antigen, suggesting the presence of serum antibodies against this antigen. Deletion mutants were then prepared to evaluate the response to serum antibodies. When serum antibody levels against WNT7B deletion mutants (WNT7B-92­2, -92­260, 2-260 and 184-260) were examined using amplified luminescence proximity homogeneous assay­linked immunosorbent assay, the levels of the antibody against WNT7B with amino acids 184­260 were higher in patients with biliary cancer than in healthy donors. Therefore, the region covering residues 184­260 of WNT7B was decomposed to generate seven peptides, and the levels of antibodies against these peptides were measured. Among them, the levels of antibodies against WNT7B234­253 and WNT7B244­260 were higher in patients with biliary cancers than in healthy donors (WNT7B234­253, P=0.0009; WNT7B244­260, P=0.0005). The levels of the antibody against the former were specifically high in patients with biliary cancer but not in those with esophageal, gastric, colorectal, pancreatic, or breast cancer. Furthermore, analysis by the cutoff value of WNT7B234­253 defined by ROC showed a high sensitivity of 70% in patients with biliary cancer. Therefore, the serum levels of the antibody against WNT7B234­253 may be useful as a marker for biliary cancer diagnosis.

Validation study of postoperative liver failure and mortality risk scores after liver resection for perihilar cholangiocarcinoma.

Background: Surgery for perihilar cholangiocarcinoma (PHCC) remains a challenging procedure with high morbidity and mortality. The Academic Medical Center (Amsterdam UMC) and Memorial Sloan Kettering Cancer Center proposed a postoperative mortality risk score (POMRS) and post-hepatectomy liver failure score (PHLFS) to predict patient outcomes. This study aimed to validate the POMRS and PHLFS for PHCC patients at Hokkaido University. Methods: Medical records of 260 consecutive PHCC patients who had undergone major hepatectomy with extrahepatic bile duct resection without pancreaticoduodenectomy at Hokkaido University between March 2001 and November 2018 were evaluated to validate the PHLFS and POMRS. Results: The observed risks for PHLF were 13.7%, 24.5%, and 39.8% for the low-risk, intermediate-risk, and high-risk groups, respectively, in the study cohort. A receiver-operator characteristic (ROC) analysis revealed that the PHLFS had moderate predictive value, with an analysis under the curve (AUC) value of 0.62. Mortality rates based on the POMRS were 1.7%, 5%, and 5.1% for the low-risk, intermediate-risk, and high-risk groups, respectively. The ROC analysis demonstrated an AUC value of 0.58. Conclusions: This external validation study showed that for PHLFS the threshold for discrimination in an Eastern cohort was reached (AUC >0.6), but it would require optimization of the model before use in clinical practice is acceptable. The POMRS were not applicable in the eastern cohort. Further external validation is recommended.

Concomitant Hepatic Artery Resection for Advanced Perihilar Cholangiocarcinoma: A Narrative Review.

Perihilar cholangiocarcinoma (PHCC) is one of the most intractable gastrointestinal malignancies. These tumours lie in the core section of the biliary tract. Patients who undergo curative surgery have a 40-50-month median survival time, and a five-year overall survival rate of 35-45%. Therefore, curative intent surgery can lead to long-term survival. PHCC sometimes invades the surrounding tissues, such as the portal vein, hepatic artery, perineural tissues around the hepatic artery, and hepatic parenchyma. Contralateral hepatic artery invasion is classed as T4, which is considered unresectable due to its "locally advanced" nature. Recently, several reports have been published on concomitant hepatic artery resection (HAR) for PHCC. The morbidity and mortality rates in these reports were similar to those non-HAR cases. The five-year survival rate after HAR was 16-38.5%. Alternative procedures for arterial portal shunting and non-vascular reconstruction (HAR) have also been reported. In this paper, we review HAR for PHCC, focusing on its history, diagnosis, procedures, and alternatives. HAR, undertaken by established biliary surgeons in selected patients with PHCC, can be feasible.

Clinical Features of Pancreatic Neuroendocrine Microadenoma: A Single-Center Experience and Literature Review.

OBJECTIVES: Pancreatic neuroendocrine microadenoma (NEMA) is a nonfunctioning neuroendocrine tumor of less than 5 mm. Most studies of NEMA were based on autopsies, and few reports have revealed the clinical frequency of NEMA. We investigated the clinicopathological features of NEMA. METHODS: The pathological results of the pancreatic resection specimens of patients, older than 18 years, who underwent pancreatic resection at Hokkaido University Hospital between April 2008 and December 2020 were retrospectively reviewed. The NEMAs were re-examined in detail and examined by immunohistochemical staining. RESULTS: Among 850 patients enrolled in this study, 24 NEMAs were identified in 12 patients (1.4%). Of the 12 patients, 2 patients had multiple endocrine neoplasia type 1, and the others had no hereditary disease, including 2 patients with multiple NEMAs. A difference in the number of NEMA was observed between patients with multiple endocrine neoplasia type 1 and sporadic NEMA. Intratumoral Ki-67 heterogeneity was correlated with the Ki-67 index. One grade 2 NEMA (Ki-67 index, 4.6%) was detected, but ATRX and DAXX labeling showed intact nuclear protein expression. CONCLUSIONS: Multiple sporadic NEMAs and grade 2 NEMAs were observed, suggesting that NEMA may have malignant potential. Thus, NEMAs should be carefully monitored for lymph node metastasis and postoperative recurrence.

Predictors of Long-Term Survival in Pancreatic Ductal Adenocarcinoma after Pancreatectomy: TP53 and SMAD4 Mutation Scoring in Combination with CA19-9.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is a fatal cancer for which even unfavorable clinicopathological factors occasionally fail to preclude long-term survival. We sought to establish a scoring system that utilizes measurable pre-intervention factors for predicting survival following surgical resection. METHODS: We retrospectively analyzed 34 patients who died from short-term recurrences and 32 long-term survivors among 310 consecutively resected patients with PDA. A logistic regression model was used to define factors related to clinical parameters, molecular profiles of 18 pancreatic cancer-associated genes, and aberrant expression of major tumor suppressors. RESULTS: Carbohydrate antigen 19-9 (CA19-9) had the best ability to classify patients with short-term recurrence and long-term survivors [odds ratio 21.04, 95% confidence interval (CI) 4.612-96.019], followed by SMAD4 and TP53 mutation scoring (odds ratio 41.322, 95% CI 3.156-541.035). Missense TP53 mutations were strongly associated with the nuclear expression of p53, whereas truncating mutations were associated with the absence of nuclear p53. The former subset was associated with a worse prognosis. The combination of aberrant SMAD4 and mutation types of TP53 exhibited a better resolution for distinguishing patients with short-term recurrences from long-term survivors (compared with the assessment of the number of mutated KRAS, CDKN2A, TP53, and SMAD4 genes). Calibration of mutation scores combined with CA19-9 in a logistic regression model setting demonstrated a practical effect in classifying long survivors and patients with early recurrence (c-statistic = 0.876). CONCLUSIONS: Genetic information, i.e., TP53 mutation types and SMAD4 abnormalities, combined with CA19-9, will be a valuable tool for improving surgical strategies for pancreatic cancer.

Bacteremia after hepatectomy and biliary reconstruction for biliary cancer: the characteristics of bacteremia according to occurrence time and associated complications.

PURPOSE: Bacteremia occurring after extensive hepatic resection and biliary reconstruction (Hx + Bx) for biliary cancer is a critical infectious complication. This study evaluated postoperative bacteremia and examined the potential usefulness of surveillance cultures. METHODS: We retrospectively reviewed 179 patients who underwent Hx + Bx for biliary cancer from January 2008 to December 2018 in our department. RESULTS: Bacteremia occurred in 41 (23.0%) patients. Patients with bacteremia had a longer operation time and more frequent intraoperative transfusion and more frequently developed organ/space surgical site infection (SSI) than those without bacteremia. The most frequently isolated bacterial species from blood cultures were Enterococcus faecium (29.3%), Enterobacter cloacae (24.4%), and Enterococcus faecalis (22.0%). The SIRS duration of bacteremia associated with organ/space SSI was significantly longer than that of other infectious complications (median 96 h vs. 48 h; p = 0.043). Bacteremia associated with organ/space SSI occurred most often by postoperative day (POD) 30. The concordance rate of bacterial species between blood and surveillance cultures within POD 30 was 67-82%. CONCLUSIONS: Bacteremia associated with organ/space SSI required treatment for a long time and typically occurred by POD 30. Postoperative surveillance cultures obtained during this period may be useful for selecting initial antibiotic therapy because of their high concordance rate with blood cultures.

A novel laparoscopic near-infrared fluorescence spectrum system with indocyanine green fluorescence overcomes limitations of near-infrared fluorescence image-guided surgery.

BACKGROUND: Near-infrared (NIR) fluorescence image-guided surgery (FIGS) introduces a revolutionary new approach to address this basic challenge in minimally invasive surgery. However, current FIGS systems have some limitations - the infrared rays cannot detect and visualise thick tissues with low concentrations of the fluorescent agent. We established a novel laparoscopic fluorescence spectrum (LFS) system using indocyanine green (ICG) fluorescence to overcome these limitations. MATERIALS AND METHODS: Bovine serum albumin (BSA) was conjugated to ICG, and the mixtures were serially diluted at 5 × 10-8-5 × 10-1 mg/mL. We used the LFS system and a NIR camera system (NLS; SHINKO OPTICAL CO., LTD Tokyo, Japan) to determine the optical dilution for the fluorescence detection. BSA was conjugated to ICG (5.0 × 10-2 mg/mL) and used to coat the clips. We attempted to identify the fluorescence-coated clip from the serosal side of the cadaveric porcine stomach tissues using the LFS system and the NIR camera system. We measured the depth of the cadaveric porcine stomach wall at the thickest part that could be confirmed. RESULTS: We could not visualise fluorescence concentrations <2.5 × 10-3 mg/mL using the NIR camera system. The spectrum was detected at a concentration <2.5 × 10-3 mg/mL. We were able to identify the spectrum of ICG (829 nm) to a 13-mm depth of cadaveric porcine stomach wall by using the LFS system but could not identify the same with the NIR camera system regardless of wall thickness. CONCLUSIONS: The novel LFS system with NIR fluorescence imaging in this ex vivo and cadaveric porcine model was confirmed useful at deeper depths and lower concentrations. Based on these findings, we anticipate that the LFS system can be integrated and routinely used in minimally invasive surgery.

Outcomes of laparoscopic total gastrectomy in elderly patients: a propensity score matching analysis.

PURPOSE: This study evaluated the short-term outcomes and prognosis after laparoscopic total gastrectomy (LTG) in elderly patients aged ≥ 80 years in a multicenter retrospective cohort study using propensity score matching. METHODS: We retrospectively enrolled 440 patients who underwent curative LTG for gastric cancer at six institutions between January 2004 and December 2018. Patients were categorized into an elderly patient group (EG; age ≥ 80 years) and non-elderly patient group (non-EG; age < 80 years). Patients were matched using the following propensity score covariates: sex, body mass index, American Society of Anesthesiologists physical status, extent of lymph node dissection, and Japanese Classification of Gastric Carcinoma stage. Short-term outcomes and prognoses were compared. RESULTS: We identified 37 propensity score-matched pairs. The median operative time was significantly shorter, and postoperative stay was longer in the EG. In terms of postoperative outcomes, the rates of all complications were comparable. The median follow-up period of the EG and non-EG was 11.5 (1-106.4) months and 35.7 (1-110.0) months, respectively; there were significant differences in 5-year overall survival between the two groups (EG, 58.5% vs. non-EG, 91.5%; P = 0.031). However, there were no significant differences in 5-year disease-specific survival (EG, 62.1% vs. non-EG, 91.5%; P = 0.068) or 5-year disease-free survival (EG, 52.9% vs. non-EG, 60.8%; P = 0.132). CONCLUSIONS: LTG seems to be safe and feasible in elderly patients. LTG had a limited effect on morbidity, disease recurrence, and survival in elderly patients. Therefore, age should not prevent elderly patients from benefitting from LTG.

Clinical and oncological benefits of left hepatectomy for Bismuth type I/II perihilar cholangiocarcinoma.

PURPOSE: This retrospective study aimed to clarify whether the postoperative prognosis differs between right and left hepatectomy for Bismuth type I/II perihilar cholangiocarcinoma. METHODS: Preoperative images of 195 patients with perihilar cholangiocarcinoma were reexamined. Patients with Bismuth type I/II perihilar cholangiocarcinoma without a difference in extraductal tumor invasion between the right and left sides of the hepatic portal region were classified into those undergoing left (L group) or right (R group) hepatectomy. RESULTS: Twenty-three patients (11.8%) were classified into the L group and 33 (16.9%) into the R group. All eight patients with pTis/1 belonged to the L group. The L group had significantly less liver failure than the R group (p = 0.001). One patient (4.3%) in the L group and four patients (12.1%) in the R group died from postoperative complications. Among 48 patients with pT2, the L group tended to have better overall survival (median, 12.2 vs. 5.6 years; p = 0.072), but not recurrence-free survival (median, 9.1 vs. 3.6 years; p = 0.477), in comparison to the R group. CONCLUSIONS: Postoperative survival after left hepatectomy for Bismuth type I/II perihilar cholangiocarcinoma is expected to be as long as that after right hepatectomy.

Targeted amplicon sequencing for primary tumors and matched lymph node metastases in patients with extrahepatic cholangiocarcinoma.

BACKGROUND: Lymph node metastasis (LNM) is one of the most adverse prognostic factors in extrahepatic cholangiocarcinoma (EHCC) cases. As next-generation sequencing technology has become more widely available, the genomic profile of biliary tract carcinoma has been clarified. However, whether LNMs have additional genomic alterations in patients with EHCC has not been investigated. Here, we aimed to compare the genomic alterations between primary tumors and matched LNMs in patients with EHCC. METHODS: Sixteen patients with node-positive EHCCs were included. Genomic DNA was extracted from tissue samples of primary tumors and matched LNMs. Targeted amplicon sequencing of 160 cancer-related genes was performed. RESULTS: Among the 32 tumor samples from 16 patients, 91 genomic mutations were identified. Genomic mutations were noted in 31 genes, including TP53, MAP3K1, SMAD4, APC, and ARID1A. TP53 mutations were most frequently observed (12/32; 37.5%). Genomic mutation profiles were highly concordant between primary tumors and matched LNMs (13/16; 81.3%), and an additional genomic mutation of CDK12 was observed in only one patient. CONCLUSION: Genomic mutations were highly concordant between primary tumors and matched LNMs, suggesting that genotyping of archived primary tumor samples may help predict genomic mutations of metastatic tumors in patients with EHCC.

Long-term survival after repetitive lymphadenectomy for nodal recurrence of pancreatic neuroendocrine neoplasms: a report of two cases.

Pancreatic neuroendocrine neoplasms (PNENs) are rare, but their incidence has increased in recent years. Curative surgery is recommended in several global guidelines for resectable PNENs. Lymph node recurrence after R0 resection for PNENs is infrequent, and global guidelines recommend surgical resection for recurrence, if resectable. However, data on the prognosis after surgical resection for nodal recurrence of PNENs are limited. We herein report two cases in which long-term survival was achieved after repetitive lymphadenectomy for nodal recurrence of PNENs. In both cases, the pathological findings for primary PNEN showed well-differentiated neuroendocrine neoplasms and R0 resection was successfully performed. The Ki-67 index increased with each resection in both cases. Both patients showed long-term survival (10 and 14 years, respectively). Repetitive lymphadenectomy for nodal recurrence of PNENs may improve patient prognosis.

Robot-assisted thoracoscopic esophagectomy for gastrointestinal stromal tumor of the esophagus: A case report.

INTRODUCTION: A gastrointestinal stromal tumor (GIST) often arises in the stomach and small intestine, while esophageal GIST is rare. The first-choice treatment is surgical resection, but there is no standard technique. Herein, we describe our experience in the treatment of esophageal GIST and discuss the usefulness of robotic esophagectomy. PRESENTATION OF CASE: The patient was a 60-year-old woman, who was diagnosed with a 30 mm GIST in the middle thoracic esophagus. We underwent robot-assisted thoracoscopic esophagectomy in the prone position. The duration of the thoracoscopic part was 69 min and the total operation time was 319 min. Total blood loss was 135 ml. The patient's postoperative course was uneventful after surgery and the patient was discharged home in good condition on the 18th postoperative day. DISCUSSION: The prognosis of esophageal GIST was less favorable compared with gastric GIST, and due to the anatomical peculiarities of the esophagus, which surgical procedure should be performed is still under debate. Robotic surgery has several technological advantages as it provides a three-dimensional view, ten times magnification, tremor control, and ambidexterity. Therefore, Robotic-assisted minimally invasive esophagectomy (RAMIE) allows achieving for safe R0 resection of esophageal GIST. CONCLUSION: RAMIE may be useful for esophageal GIST because it facilitates safe and minimally invasive surgery in a limited space of the thoracic cavity.