Global Outcomes Benchmarks in Laparoscopic Liver Surgery for Segments 7 and 8: International Multicenter Analysis.

BACKGROUND: In recent years, there has been growing interest in laparoscopic liver resection (LLR) and the audit of the results of surgical procedures. The aim of this study was to define reference values for LLR in segments 7 and 8. METHODS: Data on LLR in segments 7 and 8 between January 2000 and December 2020 were collected from 19 expert centers. Reference cases were defined as no prior hepatectomy, ASA <3, body mass index <35 kg/m2, no chronic kidney disease, no cirrhosis and portal hypertension, no chronic obstructive pulmonary disease (FEV1<80%), and no cardiac disease. Reference values were obtained from the 75th percentile of the medians of all reference centers. RESULTS: Of 585 patients, 461 (78.8%) met the reference criteria. The overall complication rate was 27.5% (6% were Clavien-Dindo≥3a) with a mean CCI of 7.5 ± 16.5. At 90-day follow-up, the references values for overall complications were 31%, Clavien≥3a 7.4%, conversion 4.4%, hospital stay < 6 days, and readmission rate < 8.33%, respectively. Eastern centers patients categorized as low risk had a lower rate of overall complications (20.9% vs 31.2%, p=0.01) with similar Clavien-Dindo≥3a (5.5% and 4.8%, p=0.83) compared to Western centers, respectively. CONCLUSION: This study shows the need to establish standards for the postoperative outcomes in LLR based on the complexity of the resection and the location of the lesions.

Novel method of intraoperative liver tumour localisation with indocyanine green and near-infrared imaging.

INTRODUCTION: Fluorescence imaging (FI) with indocyanine green (ICG) is increasingly implemented as an intraoperative navigation tool in hepatobiliary surgery to identify hepatic tumours. This is useful in minimally invasive hepatectomy, where gross inspection and palpation are limited. This study aimed to evaluate the feasibility, safety and optimal timing of using ICG for tumour localisation in patients undergoing hepatic resection. METHODS: From 2015 to 2018, a prospective multicentre study was conducted to evaluate feasibility and safety of ICG in tumour localisation following preoperative administration of ICG either on Day 0-3 or Day 4-7. RESULTS: Among 32 patients, a total of 46 lesions were resected: 23 were hepatocellular carcinomas (HCCs), 12 were colorectal liver metastases (CRLM) and 11 were benign lesions. ICG FI identified 38 (82.6%) lesions prior to resection. The majority of HCCs were homogeneous fluorescing lesions (56.6%), while CLRM were homogeneous (41.7%) or rim-enhancing (33.3%). The majority (75.0%) of the lesions not detected by ICG FI were in cirrhotic livers. Most (84.1%) of ICG-positive lesions detected were < 1 cm deep, and half of the lesions ≥ 1 cm in depth were not detected. In cirrhotic patients with malignant lesions, those given ICG on preoperative Day 0-3 and Day 4-7 had detection rates of 66.7% and 91.7%, respectively. There were no adverse events. CONCLUSION: ICG FI is a safe and feasible method to assist tumour localisation in liver surgery. Different tumours appear to display characteristic fluorescent patterns. There may be no disadvantage of administering ICG closer to the operative date if it is more convenient, except in patients with liver cirrhosis.

Current Status of Laparoscopic and Robotic Pancreatic Surgery and Its Adoption in Singapore.

Despite the potential clinical advantages offered by laparoscopic pancreatic surgery (LPS), the main obstacle to its widespread adoption is the technically demanding nature of the procedure and its steep learning curve. LPS and robotic pancreatic surgery (RPS) have been proven to result in superior short-term perioperative outcomes and equivalent long-term oncological outcomes compared to the conventional open approach, with the caveat that they are performed by expert surgeons who have been trained to perform such procedures. The primary challenge faced by most pancreatic surgeons is the steep learning curve associated with these complex procedures and the need to undergo surgical training, especially with regards to laparoscopic and robotic pancreaticoduodenectomy. Current evidence suggests that RPS may help to shorten the lengthy learning curve required for LPS. More robust evidence-in the form of large randomised controlled trials-is needed to determine whether LPS and RPS can be safely adopted universally.

First experience with robotic pancreatoduodenectomy in Singapore.

INTRODUCTION: Recent studies reported that laparoscopic pancreatoduodenectomy (LPD) is associated with superior perioperative outcomes compared to the open approach. However, concerns have been raised about the safety of LPD, especially during the learning phase. Robotic pancreatoduodenectomy (RPD) has been reported to be associated with a shorter learning curve compared to LPD. We herein present our initial experience with RPD. METHODS: A retrospective review of a single-institution prospective robotic hepatopancreaticobiliary (HPB) surgery database of 70 patients identified seven consecutive RPDs performed by a single surgeon in 2016-2017. These were matched at a 1:2 ratio with 14 open pancreatoduodenectomies (OPDs) selected from 77 consecutive pancreatoduodenectomies performed by the same surgeon between 2011 and 2017. RESULTS: Seven patients underwent RPD, of which five were hybrid procedures with open reconstruction. There were no open conversions. Median operative time was 710.0 (range 560.0-930.0) minutes. Two major morbidities (> Grade 2) occurred: one gastrojejunostomy bleed requiring endoscopic haemostasis and one delayed gastric emptying requiring feeding tube placement. There were no pancreatic fistulas, reoperations or 90-day/in-hospital mortalities in the RPD group. Comparison between RPD and OPD demonstrated that RPD was associated with a significantly longer operative time. Compared to open surgery, there was no significant difference in estimated blood loss, blood transfusion, postoperative stay, pancreatic fistula rates, morbidity and mortality rates, R0 resection rates, and lymph node harvest rates. CONCLUSION: Our initial experience demonstrates that RPD is feasible and safe in selected patients. It can be safely adopted without any compromise in patient outcomes compared to the open approach.

Multidimensional analyses reveal distinct immune microenvironment in hepatitis B virus-related hepatocellular carcinoma.

BACKGROUND AND AIMS: Chronic inflammation induced by chronic hepatitis B virus (HBV) infection increases the risk of hepatocellular carcinoma (HCC). However, little is known about the immune landscape of HBV-related HCC and its influence on the design of effective cancer immunotherapeutics. METHODS: We interrogated the immune microenvironments of HBV-related HCC and non-viral-related HCC using immunohistochemistry and cytometry by time-of-flight (CyTOF). On identifying unique immune subsets enriched in HBV-related HCC, we further interrogated their phenotypes and functions using next-generation sequencing (NGS) and in vitro T-cell proliferation assays. RESULTS: In-depth interrogation of the immune landscapes showed that regulatory T cells (TREG) and CD8+ resident memory T cells (TRM) were enriched in HBV-related HCC, whereas Tim-3+CD8+ T cells and CD244+ natural killer cells were enriched in non-viral-related HCC. NGS of isolated TREG and TRM from HBV-related HCC and non-viral-related HCC identified distinct functional signatures associated with T-cell receptor signalling, T-cell costimulation, antigen presentation and programmed cell death protein 1 (PD-1) signalling. TREG and TRM from HBV-related HCC expressed more PD-1 and were functionally more suppressive and exhausted than those from non-virus-related HCC. Furthermore, immunosuppression by PD-1+ TREG could be reversed with anti-PD-1 blockade. Using multiplexed tissue immunofluorescence, we further demonstrated that TREG and TRM contributed to overall patient survival: TREG were associated with a poor prognosis and TRM were associated with a good prognosis in HCC. CONCLUSION: We have shown that the HBV-related HCC microenvironment is more immunosuppressive and exhausted than the non-viral-related HCC microenvironment. Such in-depth understanding has important implications in disease management and appropriate application of immunotherapeutics.

Pre-operative predictors of early recurrence/mortality including the role of inflammatory indices in patients undergoing partial hepatectomy for spontaneously ruptured hepatocellular carcinoma.

BACKGROUND AND OBJECTIVES: Spontaneous rupture of Hepatocellular Carcinoma (srHCC) is a life-threatening emergency. We sought to identify the pre-operative predictors of early tumor recurrence/mortality including the role of inflammatory indices after partial hepatectomy for srHCC. METHODS: Between 2000-2015, 79 patients with srHCC were identified to have undergone upfront partial hepatectomy following srHCC. Clinicopathologic data were retrospectively analyzed to identify pre-operative predictors of early (<1 year) recurrence and mortality. RESULTS: Seventy-nine patients were identified to have undergone partial hepatectomy for srHCC. The 1-year mortality and 1-year recurrence rate in our series was 30.3% and 41.8% respectively. On multivariate analyses, free tumor rupture and a tumor size > 10 cm were identified to be independent predictors of early recurrence while an alpha fetoprotein (AFP) > 200 ng/mL was an independent predictor of early mortality. Neutrophil-to-lymphocyte ratio > 3 and prognostic nutritional index < 40 were predictors of early recurrence while PLR > 180 was a predictor of early mortality on univariate analyses but not multivariate analyses. CONCLUSIONS: Tumor size > 10 cm, free tumor rupture, and an AFP > 200 ng/mL were useful predictors in avoiding "futile surgery" in patients with srHCC undergoing a partial hepatectomy. Preoperative inflammatory markers appear to be less useful as predictors of early recurrence/mortality in this cohort of patients.

Early experience with robot-assisted laparoscopic hepatobiliary and pancreatic surgery in Singapore: single-institution experience with 20 consecutive patients.

INTRODUCTION: Experience with robot-assisted laparoscopic (RAL) hepatobiliary and pancreatic (HPB) surgery remains limited worldwide. In this study, we report our early experience with RAL HPB surgery in Singapore. METHODS: A retrospective review of the first 20 consecutive patients who underwent RAL HPB surgery at a single institution over a 34-month period from February 2013 to November 2015 was conducted. The 20 cases were performed by three principal surgeons, of which 17 (85.0%) were performed by a single surgeon. RESULTS: The median age of patients was 56 (range 22-75) years and median tumour size was 4.0 (range 1.2-7.5) cm. The surgeries performed included left-sided pancreatectomies (n = 10), hepatectomies (n = 7), triple bypass with bile duct exploration for obstructing pancreatic head cancer with choledocholithiasis (n = 1), cholecystectomy for Mirizzi's syndrome (n = 1) and gastric resection for gastrointestinal stromal tumour (n = 1). The median operation time was 445 (range 80-825) minutes and median blood loss was 350 (range 0-1,200) mL. There was only 1 (5%) open conversion. There were 2 (10.0%) major morbidities (> Grade II on the Clavien-Dindo classification) and no 30-day/in-hospital mortalities. There was no reoperation for postoperative complications. The median postoperative stay was 5.5 (range 3-22) days. CONCLUSION: Our initial experience confirms the feasibility and safety of RAL HPB surgery.

Evolution of laparoscopic liver resection at Singapore General Hospital: a nine-year experience of 195 consecutive resections.

INTRODUCTION: We aimed to analyse the changing trends, safety and outcomes associated with the adoption of laparoscopic liver resection (LLR) at a single centre. METHODS: A retrospective review of patients who underwent LLR from 2006 to 2014 at our institution was performed. To explore the evolution of LLR, the study was divided into three equal consecutive time periods (Period 1: 2006-2008, Period 2: 2009-2011, and Period 3: 2012-2014). RESULTS: Among 195 patients who underwent LLR, 24 (12.3%) required open conversions, 68 (34.9%) had resection of tumours in the difficult posterosuperior segments and 12 (6.2%) underwent major (≥ 3 segments) hepatectomies. Median operation time was 210 (range 40-620) minutes and median postoperative stay was 4 (range 1-26) days. Major postoperative morbidity (> Grade II) occurred in 11 (5.6%) patients and 90-day/in-hospital mortality was 1 (0.5%). During the study, the number of LLRs performed showed an increasing trend (Period 1: n = 22; Period 2: n = 19; Period 3: n = 154). Other statistically significant trends were: (a) increase in malignant neoplasms resected; (b) increase in resections of difficult posterosuperior segments; (c) longer median operation time; and (d) decrease in open conversion rates. CONCLUSION: Over the study period, the number of LLRs increased rapidly. LLR was increasingly performed for malignant neoplasms and lesions located in the difficult posterosuperior segments, resulting in longer operation times. However, open conversion rates decreased, and there was no change in postoperative morbidity and other perioperative outcomes.

Prognostic significance of KIT exon 11 deletion mutation in intermediate-risk gastrointestinal stromal tumor.

AIM: Benefit of adjuvant imatinib therapy following curative resection in patients with intermediate-risk gastrointestinal stromal tumor (GIST) is unclear. GIST-specific exon mutations, in particular exon 11 deletions, have been shown to be prognostic. We hypothesize that specific KIT mutations may improve risk stratification in patients with intermediate-risk GIST, identifying a subgroup of patients who may benefit from adjuvant therapy. METHODS: In total, 142 GIST patients with complete clinicopathologic and mutational data from two sites were included. Risk classification was based on the modified National Institute of Health (NIH) criteria. RESULTS: In this cohort, 74% (n = 105) of patients harbored a KIT mutation; 61% (n = 86) were found in exon 11 of which nearly 70% were KIT exon 11 deletions (n = 60). A total of 18% (n = 25) of cases were classified as having intermediate-risk disease. Univariate analysis confirmed tumor size, mitotic index, nongastric origin, presence of tumor rupture and modified NIH criteria were adversely prognostic for relapse-free survival (RFS). Among KIT/PDGFRA mutants, KIT exon 11 deletions had a significantly worse prognosis (hazard ratio 2.31; 95% confidence interval, 1.30-4.10; P = 0.003). Multivariate analysis confirmed KIT exon 11 deletion (P = 0.003) and clinical risk classification (P < 0.001) as independent adverse prognostic factors for RFS. Intermediate-risk patients harboring KIT exon 11 deletions had RFS outcomes similar to high-risk patients. CONCLUSION: The presence of KIT exon 11 deletion mutation in patients with intermediate-risk GIST is associated with an inferior clinical outcome with RFS similar to high-risk patients.

Robotic hepatectomy: initial experience of a single institution in Singapore.

INTRODUCTION: In this study, we report our initial experience with robotic hepatectomy. METHODS: Consecutive patients who underwent robotic hepatectomy at Singapore General Hospital, Singapore, from February 2013 to February 2015 were enrolled in this study. The difficulty level of operations was graded using a novel scoring system for laparoscopic hepatectomies. RESULTS: During the two-year period, five consecutive robotic hepatectomies were performed (one left lateral sectionectomy, one non-anatomical segment II/III resection, one anatomical segment V resection with cholecystectomy, one extended right posterior sectionectomy and one non-anatomical segment V/VI resection). Two hepatectomies were performed for suspected hepatocellular carcinoma, two for solitary liver metastases and one for a large symptomatic haemangioma. The median age of the patients was 53 (range 38-66) years and the median tumour size was 2.5 (range 2.1-7.3) cm. The median total operation time was 340 (range 155-825) minutes and the median volume of blood loss was 300 (range 50-1,200) mL. There were no open conversions and no mortalities or major morbidities (> Clavien-Dindo Grade II). The difficulty level of the operations was graded as low in one case (Score 2), intermediate in three cases (Score 5, 6 and 6) and high in one case (Score 10). There was one minor morbidity, where the patient experienced Grade A bile leakage, which resolved spontaneously. The median length of postoperative hospital stay was 5 (range 4-7) days. CONCLUSION: Our initial experience confirmed the feasibility and safety of robotic hepatectomy.

First experience with robotic spleen-saving, vessel-preserving distal pancreatectomy in Singapore: a report of three consecutive cases.

INTRODUCTION: The use of laparoscopic distal pancreatectomy (LDP) has increased worldwide due to the reported advantages associated with this minimally invasive procedure. However, widespread adoption is hindered by its technical complexity. Robotic distal pancreatectomy (RDP) was introduced to overcome this limitation, but worldwide experience with RDP is still lacking. There is presently evidence that RDP is associated with decreased conversion rate and increased splenic preservation as compared to LDP. METHODS: We conducted a prospective study on our initial experience with robotic spleen-saving, vessel-preserving distal pancreatectomy (SSVP-DP) between July 2013 and April 2014. RESULTS: Three consecutive patients underwent attempted robotic SSVP-DP. The indications were a 2.1-cm indeterminate cystic neoplasm, 4.5-cm solid pseudopapillary neoplasm and 1.2-cm pancreatic neuroendocrine tumour. For all three patients, the procedure was completed without conversion, and the spleen, with its main vessels, was successfully conserved. The median total operation time, blood loss and postoperative stay were 350 (range 300-540) minutes, 200 (range 50-300) mL and 7 (range 6-14) days, respectively. Two patients had minor Clavien-Dindo Grade I complications (one Grade A pancreatic fistula and one postoperative ileus). One patient had a Clavien-Dindo Grade IIIa complication (Grade B pancreatic fistula requiring percutaneous drainage). All patients were well at the time of reporting after at least six months of follow-up. CONCLUSION: Our preliminary experience with robotic SSVP-DP confirmed the feasibility of the procedure.

High-depth sequencing of over 750 genes supports linear progression of primary tumors and metastases in most patients with liver-limited metastatic colorectal cancer.

BACKGROUND: Colorectal cancer with metastases limited to the liver (liver-limited mCRC) is a distinct clinical subset characterized by possible cure with surgery. We performed high-depth sequencing of over 750 cancer-associated genes and copy number profiling in matched primary, metastasis and normal tissues to characterize genomic progression in 18 patients with liver-limited mCRC. RESULTS: High depth Illumina sequencing and use of three different variant callers enable comprehensive and accurate identification of somatic variants down to 2.5% variant allele frequency. We identify a median of 11 somatic single nucleotide variants (SNVs) per tumor. Across patients, a median of 79.3% of somatic SNVs present in the primary are present in the metastasis and 81.7% of all alterations present in the metastasis are present in the primary. Private alterations are found at lower allele frequencies; a different mutational signature characterized shared and private variants, suggesting distinct mutational processes. Using B-allele frequencies of heterozygous germline SNPs and copy number profiling, we find that broad regions of allelic imbalance and focal copy number changes, respectively, are generally shared between the primary tumor and metastasis. CONCLUSIONS: Our analyses point to high genomic concordance of primary tumor and metastasis, with a thick common trunk and smaller genomic branches in general support of the linear progression model in most patients with liver-limited mCRC. More extensive studies are warranted to further characterize genomic progression in this important clinical population.

Mucinous nonneoplastic cyst of the pancreas: a truly novel pathological entity?

Recently, a novel and distinct pancreatic cystic tumor termed "mucinous nonneoplastic" cyst was described in the literature. We report our experience with a 71-year-old female with a cystic tumor in the body of the pancreas demonstrating features suggestive of this diagnosis. We also review the literature regarding this "novel" pathological entity and discuss critically its existence and its differential diagnoses.