The impact of hospital volume on liver resection: A systematic review and Bayesian network meta-analysis

BACKGROUND

This study aims to compare the outcomes of high-volume, medium-volume, and low-volume hospitals performing hepatic resections using a network meta-analysis.

METHODS

A literature search until June 2023 was conducted across major databases to identify studies comparing outcomes in high-volume, medium-volume, and low-volume hospitals for liver resection. Bayesian network meta-analysis was conducted, and surface under cumulative ranking area values, odds ratio, and mean difference with 95% credible intervals were reported for postoperative mortality, failure-to-rescue, morbidity, length of stay, and hospital costs.

RESULTS

Twenty studies comprising 248,707 patients undergoing liver resection were included. For the primary mortality outcome, overall and subgroup analyses were performed: group I: high-volume = 5 to 20 resections/year; group II: high-volume = 21 to 49 resections/year; group III: high-volume ≥50 resections/year. Results demonstrated a significant association between hospital volume and mortality (overall-high-volume versus medium-volume: odds ratio 0.66, 95% credible interval 0.49-0.87; high-volume versus low-volume: odds ratio 0.52, 95% credible interval 0.41-0.65; group I-high-volume versus low-volume: odds ratio 0.34, 95% credible interval 0.22-0.50; medium-volume versus low-volume: odds ratio 0.56, 95% credible interval 0.33-0.92; group II-high-volume versus low-volume: odds ratio 0.67, 95% credible interval 0.45-0.91), as well as length of stay (high-volume versus low-volume: mean difference -1.24, 95% credible interval -2.07 to -0.41), favoring high-volume hospitals. No significant difference was observed in failure-to-rescue, morbidity, or hospital costs across the 3 groups.

CONCLUSION

This study supports a positive relationship between hospital volume and surgical outcomes in liver resection. Patients from high-volume hospitals experience superior outcomes in terms of lower postoperative mortality and shorter lengths of stay than medium-volume and low-volume hospitals.

Factors affecting overall survival and disease-free survival after surgery for hepatocellular carcinoma: a nomogram-based prognostic model-a Western European multicenter study

Few studies have assessed the clinical implications of the combination of different prognostic indicators for overall survival (OS) and disease-free survival (DFS) of resected hepatocellular carcinoma (HCC). This study aimed to evaluate the prognostic factors in HCC patients for OS and DFS outcomes and establish a nomogram-based prognostic model to predict the DFS of HCC. A multicenter, retrospective European study was conducted through the collection of data on 413 consecutive treated patients with a first diagnosis of HCC between January 2010 and December 2020. Univariate and multivariate Cox regression analyses were performed to identify all independent risk factors for OS and DFS outcomes. A nomogram prognostic staging model was subsequently established for DFS and its precision was verified internally by the concordance index (C-Index) and externally by calibration curves. For OS, multivariate Cox regression analysis indicated Child-Pugh B7 score (HR 4.29; 95% CI 1.74-10.55; p = 0.002) as an independent prognostic factor, along with Barcelona Clinic Liver Cancer (BCLC) stage ≥ B (HR 1.95; 95% CI 1.07-3.54; p = 0.029), microvascular invasion (MVI) (HR 2.54; 95% CI 1.38-4.67; p = 0.003), R1/R2 resection margin (HR 1.57; 95% CI 0.85-2.90; p = 0.015), and Clavien-Dindo Grade 3 or more (HR 2.73; 95% CI 1.44-5.18; p = 0.002). For DFS, multivariate Cox regression analysis indicated BCLC stage ≥ B (HR 2.15; 95% CI 1.34-3.44; p = 0.002) as an independent prognostic factor, along with multiple nodules (HR 2.04; 95% CI 1.25-3.32; p = 0.004), MVI (HR 1.81; 95% CI 1.19-2.75; p = 0.005), satellite nodules (HR 1.63; 95% CI 1.09-2.45; p = 0.018), and R1/R2 resection margin (HR 3.39; 95% CI 2.19-5.25; < 0.001). The C-Index of the nomogram, tailored based on the previous significant factors, showed good accuracy (0.70). Internal and external calibration curves for the probability of DFS rate showed optimal consistency and fit well between the nomogram-based prediction and actual observations. MVI and R1/R2 resection margins should be considered as significant OS and DFS predictors, while satellite nodules should be included as a significant DFS predictor. The nomogram-based prognostic model for DFS provides a more effective prognosis assessment for resected HCC patients, allowing for individualized treatment plans.

Extending surgical resection for hepatocellular carcinoma beyond Barcelona Clinic for Liver Cancer (BCLC) stage A: A novel application of the modified BCLC staging system

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Background: Intermediate hepatocellular carcinoma is a heterogenous group of disease. We aimed to prognosticate survival after surgical resection of HCC stratified by stage with amalgamation of the modified Barcelona Clinic Liver Cancer (BCLC) staging system and location of tumour. Methods: This single-institutional retrospective cohort study included patients with HCC who underwent surgical resection between 1st January 2000 to 30th June 2016. Participants were divided into 6 different subgroups based on the Milan Criteria (MC), the “Up-to-7” criteria, and location of lesions: A-u) Within MC with Unilobar lesions; A-b) Within MC + Bilobar lesions; B1-u) Out of MC + within Up-To-7 + Unilobar lesions; B1-b) Out of MC + within Up-to-7 + Bilobar lesions; B2-u) Out of MC + Out of Up-To-7 + Unilobar lesions; B2-b) Out of MC + Out of Up-To-7 + Bilobar lesions. A separate survival analysis was conducted for solitary HCC lesions according to three subgroups: A-S (Within MC); B1-S (Out of MC + within Up-To-7); B2-S (Out of MC + out of Up-To-7). The respective primary and secondary time-to-event outcomes were overall survival (OS) and recurrence-free survival (RFS). Results: 794 of 1043 patients with surgical resection for HCC were analysed. Groups A-u (64.6 %), A-b (58.4 %) and B1-u (56.2 %) had 5-year cumulative overall survival (OS) rates above 50% after surgical resection and median OS exceeding 60 months (P=0.0001). The 5-year cumulative recurrence-free survival rates (RFS) were 40.4% (group A-u), 38.2% (group A-b), 36.3% (group B1-u), 24.6% (group B2-u), and 7.3% (group B2-b)(P=0.0001). For solitary lesions, the 5-year OS for the subgroups were A-S (65.1%), B1-S (56.0%) and B2-S (47.1%) (P=0.0003). Compared to A-S, there was also a significant trend towards relatively poorer OS as the lesion sizes increased in B1-S (HR 1.46, 95%CI 1.03 – 2.08) and B2-S (HR 1.65, 95%CI 1.25 – 2.18). Conclusions: We adopted a novel approach combining the modified BCLC B sub-classification and dispersion of tumour to show that surgical resection may be curative in a select subgroup of patients with intermediate HCC that fall outside BCLC Stage A, specifically those with unilobar lesions and are within the “up-to-7” criteria. Furthermore, We found that size prognosticates resection outcomes in solitary tumours.

Extending Surgical Resection for Hepatocellular Carcinoma Beyond Barcelona Clinic for Liver Cancer (BCLC) Stage A: A Novel Application of the Modified BCLC Staging System

Objective

We aimed to prognosticate survival after surgical resection of HCC stratified by stage with amalgamation of the modified Barcelona Clinic Liver Cancer (BCLC) staging system and location of tumour.

Methods

This single-institutional retrospective cohort study included patients with HCC who underwent surgical resection between 1st January 2000 to 30th June 2016. Participants were divided into 6 different subgroups: A-u) Within MC with Unilobar lesions; A-b) Within MC + Bilobar lesions; B1-u) Out of MC + within Up-To-7 + Unilobar lesions; B1-b) Out of MC + within Up-to-7 + Bilobar lesions; B2-u) Out of MC + Out of Up-To-7 + Unilobar lesions; B2-b) Out of MC + Out of Up-To-7 + Bilobar lesions. A separate survival analysis was conducted for solitary HCC lesions according to three subgroups: A-S (Within MC); B1-S (Out of MC + within Up-To-7); B2-S (Out of MC + out of Up-To-7).

Results

A total of 794 of 1043 patients with surgical resection for HCC were analysed. Groups A-u (64.6%), A-b (58.4%) and B1-u (56.2%) had 5-year cumulative overall survival (OS) rates above 50% after surgical resection and median OS exceeding 60 months (P = 0.0001). The 5-year cumulative recurrence-free survival rates (RFS) were 40.4% (group A-u), 38.2% (group A-b), 36.3% (group B1-u), 24.6% (group B2-u), and 7.3% (group B2-b)(P=0.0001). For solitary lesions, the 5-year OS for the subgroups were A-S (65.1%), B1-S (56.0%) and B2-S (47.1%) (P = 0.0003). Compared to A-S, there was also a significant trend towards relatively poorer OS as the lesion sizes increased in B1-S (HR 1.46, 95% CI 1.03–2.08) and B2-S (HR 1.65, 95% CI 1.25–2.18).

Conclusion

We adopted a novel approach combining the modified BCLC B sub-classification and dispersion of tumour to show that surgical resection in intermediate stage HCC can be robustly prognosticated. We found that size prognosticates resection outcomes in solitary tumours.

Resected pancreatic adenocarcinoma: An Asian institution's experience

BACKGROUND

Pancreatic adenocarcinoma (PDAC) is highly lethal. Surgery offers the only chance of cure, but 5-year overall survival (OS) after surgical resection and adjuvant therapy remains dismal. Adjuvant trials were mostly conducted in the West enrolling fit patients. Applicability to a general population, especially Asia has not been described adequately.

AIM

We aimed to evaluate the clinical outcomes, prognostic factors of survival, pattern, and timing of recurrence after curative resection in an Asian institution.

METHODS AND RESULTS

The clinicopathologic and survival outcomes of 165 PDAC patients who underwent curative resection between 1998 and 2013 were reviewed retrospectively. Median age at surgery was 62.0 years. 55.2% were male, and 73.3% had tumors involving the head of pancreas. The median OS of the entire cohort was 19.7 months. Median OS of patients who received adjuvant chemotherapy was 23.8 months. Negative predictors of survival include lymph node ratio (LNR) of >0.3 (HR = 3.36, P = .001), tumor site involving the body or tail of pancreas (HR = 1.59, P = .046), presence of perineural invasion (PNI) (HR = 2.36, P = .018) and poorly differentiated/undifferentiated tumor grade (HR = 1.86, P = .058). The median time to recurrence was 8.87 months, with 66.1% and 81.2% of patients developing recurrence at 12 months and 24 months respectively. The most common site of recurrence was the liver.

CONCLUSION

The survival of Asian patients with resected PDAC who received adjuvant chemotherapy is comparable to reported randomized trials. Clinical characteristics seem similar to Western patients. Hence, geographical locations may not be a necessary stratification factor in RCTs. Conversely, lymph node ratio and status of PNI ought to be incorporated.

Time-varying prognostic effects of primary tumor sidedness and grade after curative liver resection for colorectal liver metastases

BACKGROUND

The veracity of the proportional hazards (PH) requirement is rarely scrutinized in most areas of cancer research, although fulfilment of this assumption underpins widely-used Cox survival models. We sought to critically appraise the existence of prognostic factors with time-dependent effects and to characterize their impact on survival among CLM patients.

METHODS

Consecutive patients who underwent liver resection with curative intent for CLM at the Singapore General Hospital were identified from a prospectively-maintained database. We evaluated PH of 55 candidate variables, and parameters which departed significantly from proportionality were included in Cox models that incorporated an interaction term to account for time-dependent effects. As sensitivity analyses, we fitted Weibull mixture 'cure' models to handle long plateaus in the tails of survival curves, and also analyzed the restricted mean survival time.

RESULTS

318 consecutive patients who underwent curative liver resection for CLM between Jan 2000 and Nov 2016 were included in this analysis. Hazard ratios for tumor grade (poorly-versus well- and moderately-differentiated) were found to decrease from 3.135 (95% CI: 1.637-6.003) at 12 months to 2.048 (95% CI: 1.038-4.042) after 24 months, and ceased to be significant at 26 months. Compared to left-sided tumors, a right-sided tumor location was found to portend worse prognosis for the first 10 months after resection but subsequently confer a survival benefit due to a crossing of survival curves. Corroborating this observation, long-term cure fractions were estimated to be 25.5% (95% CI: 17.4%-33.6%) and 34.2% (95% CI: 17.4%-50.9%) among patients with left-sided and right-sided primary disease respectively.

CONCLUSION

Primary tumor sidedness and grade appear to exert time-varying prognostic effects in CLM patients undergoing curative liver resection.

Elevated Right Hemidiaphragm: A Clue in Acute Cholecystitis?

Two patients presented to the Emergency Department with sepsis and vague localising complaints. Both of them had a new elevation of the right hemidiaphragm on chest radiography and were eventually diagnosed with complicated acute cholecystitis on CT imaging. In both cases, the hemidiaphragmatic elevation could not be explained by mass effect as there was no sizable intra-abdominal collection. One of the patients was initially misdiagnosed with pneumonia, resulting in clinical deterioration due to delay in definitive management. Awareness of this phenomenon is essential to avoid pitfalls in patients with acute cholecystitis, especially for those who do not present in a typical manner.

Comparison between long and short-term venous patencies after pancreatoduodenectomy or total pancreatectomy with portal/superior mesenteric vein resection stratified by reconstruction type

Background

Venous reconstruction has been recently demonstrated to be safe for tumours with invasion into portal vein and/or superior mesenteric vein. This study aims to compare the patency between various venous reconstructions.

Methods

This is retrospective study of 76 patients who underwent pancreaticoduodenectomy or total pancreatectomy with venous reconstruction from 2006 to 2018. Patient demographics, tumour histopathology, morbidity, mortality and patency were studied. Kaplan-Meier estimates were performed for primary venous patency.

Results

Sixty-two patients underwent pancreaticoduodenectomy and 14 underwent total pancreatectomy. Forty-seven, 19 and 10 patients underwent primary repair, end-to-end anastomosis and interposition graft respectively. Major morbidity (Clavien-Dindo >grade 2) and 30-day mortality were 14/76(18.4%) and 1/76(1.3%) respectively. There were 12(15.8%) venous occlusion including 4(5.3%) acute occlusions. Overall 6-month, 1-year and 2-year primary patency was 89.1%, 92.5% and 92.3% respectively. 1-year primary patency of primary repair was superior to end-to-end anastomosis and interposition graft (primary repair 100%, end-to-end anastomosis 81.8%, interposition graft 66.7%, p = 0.045). Pairwise comparison also demonstrated superior 1-year patency of primary repair (adjusted p = 0.037). There was no significant difference between the cumulative venous patency for each venous reconstruction method: primary repair 84±6%, end-to-end anastomosis 75±11% and interposition graft 76±15% (p = 0.561).

Conclusion

1-year primary venous patency of primary repair is superior to end-to-end anastomosis and interposition graft.

Adoption of Robotic Liver, Pancreatic and Biliary Surgery in Singapore: A Single Institution Experience with Its First 100 Consecutive Cases

INTRODUCTION

Presently, robotic hepatopancreatobiliary surgery (RHPBS) is increasingly adopted worldwide. This study reports our experience with the first 100 consecutive cases of RHPBS in Singapore.

METHODS

Retrospective review of a single-institution prospective database of the first 100 consecutive RHPBS performed over 6 years from February 2013 to February 2019. Eighty-six cases were performed by a single surgeon.

RESULTS

The 100 consecutive cases included 24 isolated liver resections, 48 pancreatic surgeries (including 2 bile duct resections) and 28 biliary surgeries (including 8 with concomitant liver resections). They included 10 major hepatectomies, 15 pancreaticoduodenectomies, 6 radical resections for gallbladder carcinoma and 8 hepaticojejunostomies. The median operation time was 383 minutes, with interquartile range (IQR) of 258 minutes and there were 2 open conversions. The median blood loss was 200ml (IQR 350ml) and 15 patients required intra-operative blood transfusion. There were no post-operative 90-day nor in-hospital mortalities but 5 patients experienced major (> grade 3a) morbidities. The median post-operative stay was 6 days (IQR 5 days) and there were 12 post-operative 30-day readmissions. Comparison between the first 50 and the subsequent 50 patients demonstrated a significant reduction in blood loss, significantly lower proportion of malignant indications, and a decreasing frequency in liver resections performed.

CONCLUSION

Our experience with the first 100 consecutive cases of RHPBS confirms its feasibility and safety when performed by experienced laparoscopic hepatopancreatobiliary surgeons. It can be performed for even highly complicated major hepatopancreatobiliary surgery with a low open conversion rate.

Impact of multidisciplinary tumour boards (MTB) on the clinicopathological characteristics and outcomes of resected colorectal liver metastases across time

Background

Resection of colorectal liver metastases (CLM) has been established as the standard of care. This study aims to compare the change in clinicopathological characteristics of patients who underwent curative resection of CLM across two time periods—2000 to 2010 (P1) and 2011 to 2016 (P2) and evaluate the prognostic impact of these characteristics on survival outcomes.

Methods

Patients who undergo liver resection for CLM at Singapore General Hospital from January 2000 to December 2016 were identified from a prospectively maintained database. The primary end point was overall survival.

Results

There were 183/318 (57.5%) patients and 135/318 (42.5%) patients in P1 and P2, respectively. There was a lower proportion of patients who had nodal metastases from primary colorectal cancer and clinical risk score (CRS) less than 3 in P2 when compared to P1. There was no difference in survival between both time periods. Independent predictors of survival for the cohort were CEA levels ≥ 200 ng/ml, primary tumour grade and lymph nodal status. Independent predictors of poor survival in P1 were poorly differentiated colorectal cancer and nodal metastases while in P2, independent predictors of poor survival were multiple liver metastases and nodal metastases.

Conclusion

Nodal metastases from primary colorectal cancer are an independent predictor of poor survival across time for resectable CLM. Although there is no difference in survival between the two time periods, patients with multiple liver metastases should be carefully considered prior to surgery as it is also an independent predictor of overall survival.

Effect of remote ischemic preConditioning on liver injury in patients undergoing liver resection: the ERIC-LIVER trial

OBJECTIVE

Novel hepatoprotective strategies are needed to improve clinical outcomes during liver surgery. There is mixed data on the role of remote ischemic preconditioning (RIPC). We investigated RIPC in partial hepatectomy for primary hepatocellular carcinoma (HCC).

METHODS

This was a Phase II, single-center, sham-controlled, randomized controlled trial (RCT). The primary hypothesis was that RIPC would reduce acute liver injury following surgery indicated by serum alanine transferase (ALT) 24 h following hepatectomy in patients with primary HCC, compared to sham. Patients were randomized to receive either four cycles of 5 min/5 min arm cuff inflation/deflation immediately prior to surgery, or sham. Secondary endpoints included clinical, biochemical and pathological outcomes. Liver function measured by Indocyanine Green pulse densitometry was performed in a subset of patients.

RESULTS

24 and 26 patients were randomized to RIPC and control groups respectively. The groups were balanced for baseline characteristics, except the duration of operation was longer in the RIPC group. Median ALT at 24 h was similar between groups (196 IU/L IQR 113.5-419.5 versus 172.5 IU/L IQR 115-298 respectively, p = 0.61). Groups were similar in secondary endpoints.

CONCLUSION

This RCT did not demonstrate beneficial effects with RIPC on serum ALT levels 24 h after partial hepatectomy.

Early Prediction of Post-hepatectomy Liver Failure in Patients Undergoing Major Hepatectomy Using a PHLF Prognostic Nomogram

BACKGROUND

Liver resection (LR) is the main modality of treatment for hepatocellular carcinoma (HCC) and colorectal liver metastasis (CRLM). Post-hepatectomy liver failure (PHLF) remains the most dreaded complication. We aim to create a prognostic score for early risk stratification of patients undergoing LR.

METHODOLOGY

Clinical and operative data of 472 patients between 2000 and 2016 with HCC or CRLM undergoing major hepatectomy were extracted and analysed from a prospectively maintained database. PHLF was defined using the 50-50 criteria.

RESULTS

Liver cirrhosis and fatty liver were histologically confirmed in 35.6% and 53% of patients. 4.7% (n = 22) of patients had PHLF. A 90-day mortality was 5.1% (n = 24). Pre-operative albumin-bilirubin score (p = 0.0385), prothrombin time (p < 0.0001) and the natural logarithm of the ratio of post-operative day 1 to pre-operative serum bilirubin (SB) (ln(_POD1Bil/_pre-opBil); p < 0.0001) were significantly independent predictors of PHLF. The PHLF prognostic nomogram was developed using these factors with receiver operating curve showing area under curve of 0.88. Excellent sensitivity (94.7%) and specificity (95.7%) for the prediction of PHLF (50-50 criteria) were achieved at cut-offs of 9 and 11 points on this model. This score was also predictive of PHLF according to _PeakBil > 7 and International Study Group for Liver Surgery criteria, intensive care unit admissions, length of stay, all complications, major complications, re-admissions and mortality (p < 0.05).

CONCLUSIONS

The PHLF nomogram ( https://tinyurl.com/SGH-PHLF-Risk-Calculator ) can serve as a useful tool for early identification of patients at high risk of PHLF before the 'point of no return'. This allows enforcement of closer monitoring, timely intervention and mitigation of adverse outcomes.

Survival Advantage of Laparoscopic Versus Open Resection For Colorectal Liver Metastases: A Meta-analysis of Individual Patient Data From Randomized Trials and Propensity-score Matched Studies

OBJECTIVE

To perform an individual participant data meta-analysis using randomized trials and propensity-score matched (PSM) studies which compared laparoscopic versus open hepatectomy for patients with colorectal liver metastases (CLM).

BACKGROUND

Randomized trials and PSM studies constitute the highest level of evidence in addressing the long-term oncologic efficacy of laparoscopic versus open resection for CLM. However, individual studies are limited by the reporting of overall survival in ways not amenable to traditional methods of meta-analysis, and violation of the proportional hazards assumption.

METHODS

Survival information of individual patients was reconstructed from the published Kaplan-Meier curves with the aid of a computer vision program. Frequentist and Bayesian survival models (taking into account random-effects and nonproportional hazards) were fitted to compare overall survival of patients who underwent laparoscopic versus open surgery. To handle long plateaus in the tails of survival curves, we also exploited "cure models" to estimate the fraction of patients effectively "cured" of disease.

RESULTS

Individual patient data from 2 randomized trials and 13 PSM studies involving 3148 participants were reconstructed. Laparoscopic resection was associated with a lower hazard rate of death (stratified hazard ratio = 0.853, 95% confidence interval: 0.754-0.965, P = 0.0114), and there was evidence of time-varying effects (P = 0.0324) in which the magnitude of hazard ratios increased over time. The fractions of long-term cancer survivors were estimated to be 47.4% and 18.0% in the laparoscopy and open surgery groups, respectively. At 10-year follow-up, the restricted mean survival time was 8.6 months (or 12.1%) longer in the laparoscopy arm (P < 0.0001). In a subgroup analysis, elderly patients (≥65 years old) treated with laparoscopy experienced longer 3-year average life expectancy (+6.2%, P = 0.018), and those who live past the 5-year milestone (46.1%) seem to be cured of disease.

CONCLUSIONS

This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for CLM in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.

Pre-operative Imaging Characteristics in Histology-Proven Resected Intrahepatic Cholangiocarcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common primary liver cancers. With the increasing incidence of ICC over the past two decades in Asia, it is essential to differentiate between HCC and ICC. However, ICC may mimic the radiological appearance of HCC on computed tomography scans (CT) and magnetic resonance imaging (MRI), leading to misdiagnosis of ICC. The objective of this study is to evaluate and describe the association of specific pre-operative imaging characteristics (arterial enhancement, portal venous washout) in patients with histologically proven resected ICC in our centre.

METHODS

Data on patients with histology-proven ICC and mixed hepatocellular-cholangiocarcinomas (HCC-CC) who had undergone surgical resection at Singapore General Hospital (SGH) were identified from a prospectively maintained database. Pre-operative cross-sectional imaging reports were analysed.

RESULTS

Ninety-one patients underwent resection between 1 January 2000 and 31 December 2016. Among those with no risk factors for HCC, a significant percentage of patients with ICC (24.3%) show imaging characteristics of both arterial phase hyperenhancement and non-peripheral venous washout. Among patients with risk factors for HCC, between 20.0 and 33.3% of patients with pure ICC fulfilled the imaging criteria for HCC, and this proportion was generally even higher in the mixed HCC-CC group.

CONCLUSIONS

A significant proportion of patients with pure ICC showed pre-operative imaging characteristics which fulfilled the diagnostic criteria for HCC. The differential of ICC should be borne in mind in populations where both malignancies are endemic.

Outcome of minimally-invasive versus open pancreatectomies for solid pseudopapillary neoplasms of the pancreas: A 2:1 matched case-control study

Backgrounds/Aims

Solid pseudopapillary neoplasm (SPPN) is typically seen in young healthy females who would likely benefit from minimally-invasive pancreatectomy (MIP). A few comparative studies have suggested that MIP is associated with favorable outcomes when compared to the open approach for SPPN. This study aims to mitigate potential selection bias by performing a matched case-control study comparing MIP vs open pancreatectomy (OP) for SPPN.

Methods

We performed a single-institution retrospective electronic chart review of all patients who underwent surgery for pathologically confirmed SPPN between 2000 and 2017. A 2:1 matched comparison using age, gender, tumor size and the type of pancreatectomy was performed between OP and MIP.

Results

A total of 40 patients with a median age of 40.3 years (range 16.5-64.4) and female sex predominance (n=34, 85.0%) underwent surgery during the study period. Nine patients underwent MIP. Matched comparison between 18 OP and 9 MIP demonstrated that MIP was associated with a longer median operating time (305 vs 180 min, p=0.046) and shorter median postoperative stay (6 vs 9 days, p=0.015). There were no significant differences in intraoperative blood loss, blood transfusion requirements, postoperative morbidity (including postoperative pancreatic fistula) and mortality, resection margins, lymph node yield and long-term survival.

Conclusions

MIP is a safe and viable option in the management of SPPN with the benefit of a shorter postoperative length of stay at the expense of a longer operation time. There was no significant difference in oncologic outcomes between both groups of patients.

Liver Resection for Nonalcoholic Fatty Liver Disease-Associated Hepatocellular Carcinoma

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (HCC) is on the rise worldwide, but data on long-term outcomes after curative operations are limited. The primary aim of this study was to characterize the perioperative and long-term outcomes after liver resection. The secondary aim was to investigate the influence of the histologic severity of nonalcoholic steatohepatitis and its impact on perioperative outcomes and long-term survival.

METHODS

A total of 996 patients who underwent liver resection for HCC in our institution were analyzed. Patients were categorized into subgroups of NAFLD vs non-NAFLD HCC based on histologic evidence of hepatic steatosis. Comparisons of patients' demographic, clinical, and surgical characteristics; postoperative complications; and survival outcomes were performed.

RESULTS

Eight hundred and forty-four patients had non-NAFLD HCC and 152 patients had NAFLD HCC. Comorbidities were significantly more common in the NAFLD group (p < 0.0001). In the non-NAFLD group, larger median tumor size, higher liver cirrhosis, and lower median neutrophil to lymphocyte ratio were observed (p < 0.0001). The NAFLD group had a greater amount of intraoperative blood loss, more postoperative complications, and longer length of stay. Five-year overall survival was significantly better in the NAFLD group (p = 0.0355). Significant factors that contribute to poorer survival outcomes include age, congestive cardiac failure, Child-Pugh's class B, cirrhosis, tumor size, multinodularity, and R1 resection. For NAFLD group, patients with abnormal parenchyma showed poorer survival and 5-year overall survival rates (64.8% vs 75.6%; p = 0.2291).

CONCLUSIONS

Nonalcoholic fatty liver disease-related HCC is associated with greater surgical morbidity and post-hepatectomy liver failure. Despite this, long-term survival outcomes are favorable compared with non-NAFLD etiologies.

Laparoscopic Liver Resection Difficulty Score-a Validation Study

OBJECTIVE(S)

The technical complexity of laparoscopic liver resection (LLR) poses unique challenges distinct from open surgery. An objective scoring system was developed that preoperatively quantifies the difficulty of LRR to help guide surgeon decision-making regarding the feasibility and safety of minimally invasive approaches. The aim of this multiinstitutional study was to externally validate this scoring system.

METHODS

Patients who underwent LLR at two institutions were reviewed. LLR difficulty score (LDS) was calculated based on patient, tumor, and anatomic characteristics by two independent, blinded hepatobiliary surgeons. Surrogates of case complexity (e.g., conversion rate, operative time) were used for validation of this index.

RESULTS

From 2006 to 2016, 444 LLR were scored as low (n = 94), intermediate (n = 98), and high difficulty (n = 152) with respective conversion rates of 5.3%, 15.7%, and 25%. Cases of higher LDS correlated with larger mean blood loss (203 ml vs. 331 ml vs. 635 ml). Mean operative and Pringle maneuver used were associated with increasing LDS (155 min vs. 202 min vs. 315 min and 14.4% vs. 29.7% vs. 45.1% respectively). These operative surrogates of difficulty correlated significantly with the LDS (all p < 0.0001).

CONCLUSIONS

This comprehensive external validation of the LDS is robust and applicable in diverse patient populations. This LDS serves as a useful objective predictor of technical difficulty for LLR to help surgeons in selecting patients according to their individual operative experience and is valuable for preoperative risk estimation and stratification in randomized trials.

A retrospective review of correlative radiological assessment and surgical exploration for hilar cholangiocarcinoma

Backgrounds/Aims

Hilar cholangiocarcinomas (HCCAs) are tumors that involve the biliary confluence; at present, radical surgery offers the only chance of long-term survival, but this can be challenging given the complexity of the hilar anatomy. Blumgart and Jarnagin described a preoperative staging system that incorporates the effect of local tumor extent and its impact on adjacent structures and that has been demonstrated to correlate better with actual surgical resectability. The primary aim of this study is to describe the correlation between preoperative Blumgart-Jarnagin staging and its correlation with surgical resectability.

Methods

Patients who underwent surgical resection for hilar cholangiocarcinoma at Singapore General Hospital between January 1, 2002, and January 1, 2013, were identified from a prospectively maintained institutional database. All patients were staged based on the criteria described by Blumgart and Jarnagin. Correlation with surgical resectability was then determined.

Results

A total of 19 patients were identified. Overall resectability was 57.8% (n=11). Patients with Blumgart-Jarnagin stage T1 had the highest rates of resectability at 80%; patients with stage T2 and T3 disease had resectability rates of 25% and 40% respectively. Median overall survival was 13.6 months.

Conclusions

The Blumgart-Jarnagin staging system is useful for predicting tumor resectability in HCCA.

Predictors of post-hepatectomy liver failure in patients undergoing extensive liver resections for hepatocellular carcinoma

Backgrounds/Aims

To determine the prevalence of post-hepatectomy liver failure/insufficiency (PHLF/I) in patients undergoing extensive hepatic resections for hepatocellular carcinoma (HCC) and to assess the predictive value of preoperative factors for post-hepatectomy liver failure or insufficiency (PHLF/I).

Methods

A retrospective review of patients who underwent liver resections for HCC between 2001 and 2013 was conducted. Preoperative parameters were assessed and analyzed for their predictive value of PHLF/I. Definitions used included the 50–50, International Study Group of Liver Surgery (ISGLS) and Memorial Sloan Kettering Cancer Centre (MSKCC) criteria.

Results

Among the 848 patients who underwent liver resections for HCC between 2001 and 2013, 157 underwent right hepatectomy (RH) and extended right hepatectomy (ERH). The prevalence of PHLF/I was 7%, 41% and 28% based on the 50–50, ISGLS and MSKCC criteria, respectively. There were no significant differences in PHLF/I between RH and ERH. Model for End-Stage Liver Disease (MELD) score and bilirubin were the strongest independent predictors of PHLF/I based on the 50–50 and ISGLS/MSKCC criteria, respectively. Predictive models were developed for each of the criteria with multiple logistic regression.

Conclusions

MELD score, bilirubin, alpha-fetoprotein and platelet count showed significant predictive value for PHLF/I (all p<0.05). A composite score based on these factors serves as guideline for physicians to better select patients undergoing extensive resections to minimize PHLF.

Changes in operative experience after the introduction of residency: an objective comparison of surgical and endoscopic volumes

INTRODUCTION

The SingHealth Residency General Surgery Programme replaced the basic and advanced specialist training (AST) system in Singapore in 2010. The relative merits of both systems continue to be debated, especially the operational readiness of graduating residents. We set out to compare the operative and endoscopic volumes of graduates from the AST system with those from the first graduating batch of the residency programme during their registrar (or equivalent) years, as a reflection of procedural experience gained during traineeship.

METHODS

Operative and endoscopic records of four graduating residents and seven AST system trainees were extracted from the cluster-wide Operating Theatre Management system and compared. Surgeries were analysed as registrar-level operations and their corresponding subspecialties.

RESULTS

Registrars and senior residents performed a mean of 1,182 and 533 general surgical operations, respectively. Median percentage loss in operative volume was 50.6% (range 9.6%-75.5%). The mean number of total gastroscopies and colonoscopies performed by registrars (total gastroscopy, n = 819; total colonoscopy, n = 743) and senior residents (total gastroscopy, n = 376; total colonoscopy, n = 412) indicated a mean loss of 54.1% and 44.6%, respectively, in gastroscopic and colonoscopic experience.

CONCLUSION

The residency programme aims to provide robust and complete surgical training. The operational readiness of its graduates is often scrutinised against that from the old system. Although a significant difference in surgical and endoscopic volumes was observed between the two trainee groups, this is only one marker of surgical experience and technical competence.

Prediction of Hepatocellular Carcinoma Recurrence Beyond Milan Criteria After Resection: Validation of a Clinical Risk Score in an International Cohort

OBJECTIVE

This study aims to validate a previously reported recurrence clinical risk score (CRS).

SUMMARY OF BACKGROUND DATA

Salvage transplantation after hepatocellular carcinoma (HCC) resection is limited to patients who recur within Milan criteria (MC). Predicting recurrence patterns may guide treatment recommendations.

METHODS

An international, multicenter cohort of R0 resected HCC patients were categorized by MC status at presentation. CRS was calculated by assigning 1 point each for initial disease beyond MC, multinodularity, and microvascular invasion. Recurrence incidences were estimated using competing risks methodology, and conditional recurrence probabilities were estimated using the Bayes theorem.

RESULTS

From 1992 to 2015, 1023 patients were identified, of whom 613 (60%) recurred at a median follow-up of 50 months. CRS was well validated in that all 3 factors remained independent predictors of recurrence beyond MC (hazard ratio 1.5-2.1, all P < 0.001) and accurately stratified recurrence risk beyond MC, ranging from 19% (CRS 0) to 67% (CRS 3) at 5 years. Among patients with CRS 0, no other factors were significantly associated with recurrence beyond MC. The majority recurred within 2 years. After 2 years of recurrence-free survival, the cumulative risk of recurrence beyond MC within the next 5 years for all patients was 14%. This risk was 12% for patients with initial disease within MC and 17% for patients with initial disease beyond MC.

CONCLUSIONS

CRS accurately predicted HCC recurrence beyond MC in this international validation. Although the risk of recurrence beyond MC decreased over time, it never reached zero.

Genomic and proteomic characterization of ARID1A chromatin remodeller in ampullary tumors

AT rich interactive domain 1A (ARID1A) is one of the most commonly mutated genes in a broad variety of tumors. The mechanisms that involve ARID1A in ampullary cancer progression remains elusive. Here, we evaluated the frequency of ARID1A and KRAS mutations in ampullary adenomas and adenocarcinomas and in duodenal adenocarcinomas from two cohorts of patients from Singapore and Romania, correlated with clinical and pathological tumor features, and assessed the functional role of ARID1A. In the ampullary adenocarcinomas, the frequency of KRAS and ARID1A mutations was 34.7% and 8.2% respectively, with a loss or reduction of ARID1A protein in 17.2% of the cases. ARID1A mutational status was significantly correlated with ARID1A protein expression level (P=0.023). There was a significant difference in frequency of ARID1A mutation between Romania and Singapore (2.7% versus 25%, P=0.04), suggestive of different etiologies. One somatic mutation was detected in the ampullary adenoma group. In vitro studies indicated the tumor suppressive role of ARID1A. Our results warrant further investigation of this chromatin remodeller as a potential early biomarker of the disease, as well as identification of therapeutic targets in ARID1A mutated ampullary cancers.

A case of small bowel metastasis from spinal Ewing sarcoma causing intussusception in an adult female

Background

Ewing sarcomas are highly aggressive malignant tumours occurring predominantly in the long bones of the extremities in children and young adults. About 20 % of patients will present with metastases at diagnosis with the commonest sites being the lungs, bone and bone marrow. Cases of primary small bowel Ewing sarcomas have been described but are nonetheless exceedingly rare, even more so cases of metastasis to the small bowel.

Case Presentation

We describe a case of vertebral Ewing sarcoma in a 44 year-old female which metastasized to the jejunum causing intussusception.

Conclusions

Ewing’s sarcoma is highly aggressive and presence of metastases, overt or subclinical, is thought to be present in almost all patients at diagnosis. As evidenced by our patient, metastatic disease can progress rapidly to cause further complications and confer a poorer survival. The possibility of metastasis, no matter how rare or unlikely the site is, should be considered and actively investigated to expedite treatment of the primary disease.

Laparoscopic liver resection for posterosuperior and anterolateral lesions-a comparison experience in an Asian centre

BACKGROUND

Minimally invasive surgery has been one of the recent developments in liver surgery, laparoscopic liver resection (LLR) was initially performed for benign lesions at easily accessible locations. As the surgical techniques, technology and experience improved over the past decades, LLR surgery had evolved to tackle malignant lesions, major resections and even in difficult locations without compromising safety and principles of oncology. It was also shown to be beneficial in cirrhotic patients. We describe our initial experience with LLR in a population with significant proportion having cirrhosis, emphasising our approach for lesions in the posterosuperior (PS) segments of the liver (segments 1, 4a, 7, and 8).

METHODS

A review of patients undergoing LLR in single institution from 2006 to 2015 was performed from a prospective surgical database. Clinicopathological, operative and perioperative parameters were analyzed to compare outcomes in patients who underwent LLR for PS vs. anterolateral lesions (AL).

RESULTS

LLR was performed in consecutive 197 patients, with a mean age of 60 years. The indications for resection were hepatocellular carcinoma (HCC) (n=105; 53%), colorectal cancer liver metastasis (n=31; 16%), other malignancies (n=19; 10%) and benign lesions (n=42; 21%). A significant proportion had liver cirrhosis (25.9%). More females underwent surgery in the AL group and indications for surgery were similar between both groups. Major liver resection was performed more frequently for the PS group than for the AL group (P<0.001) and significantly more PS resections was performed in our latter experience (P=0.02). The mean operative time and the conversion rate were significantly greater in the PS group than in the AL group (P≤0.001 and 0.03, respectively). However, the estimated blood loss (EBL), rate of blood transfusion and mean postoperative stay were similar in the two groups (P=0.04, 0.88 and 0.92, respectively). The overall 90-day morbidity and mortality rate was 21.3% and 0.5% respectively, with no differences between the two groups. Surrogates of difficulty such as operative time, blood loss, conversion and outcomes e.g., morbidity and mortality, were similar in patients who underwent PS resections with or without cirrhosis.

CONCLUSIONS

LLR in selected patients is technically feasible and safe including cirrhotic patients with lesions in the PS segments.

Underlying liver disease influences volumetric changes in the spared hemiliver after selective internal radiation therapy with 90Y in patients with hepatocellular carcinoma

OBJECTIVE

Hypertrophy of the contralateral liver lobe after treatment with yttrium-90 ((90)Y) microspheres has recently been reported. This study aimed to quantify left hepatic lobe hypertrophy after right-sided radioembolization for hepatocellular carcinoma (HCC) and to identify pretreatment predictive factors of hypertrophy in an Asian population.

METHODS

A retrospective review of patients with inoperable HCC undergoing selective internal radiation treatment (SIRT) with (90)Y microspheres at a single institution from January 2008 to January 2012 was performed. Only patients who had treatment delivered via the right hepatic artery alone were included.

RESULTS

In all, 17 patients fulfilling the study criteria were identified. The mean percentage of left-lobe hypertrophy was 34.2% ± 34.9% (range 19.0-106.5%) during a median of 5-month follow-up. Patients with hepatitis B were found to experience a significantly greater degree of hypertrophy than those with hepatitis C or alcoholic liver cirrhosis. There were no cases of acute liver failure after the administration of SIRT in this study and none of the patients developed disease in the contralateral lobe over the study period.

CONCLUSIONS

Administration of unilobar SIRT to the right liver lobe in patients with HCC resulted in a significant degree of contralateral left lobe hypertrophy. Patients with hepatitis B experienced a greater degree of hypertrophy than those with hepatitis C or alcoholic liver cirrhosis.

Treatment of right-sided hepatocellular carcinoma with uni-lobar y-90 radioembolisation and induction of hypertrophy in the the contralateral left lobe

e15102

Background: Yttrium-90 microsphere (Y90) is currently used to treat locally advanced hepatocellular carcinoma (HCC) including those where resection is precluded because of inadequate future remnant liver. Hypertrophy of the contralateral lobe after Y90 treatment has been reported. This study aims to quantify this hypertrophy and identify factors predictive of this response. Methods: Radiological review of patients undergoing Y-90 with treatment delivered via right hepatic artery for advanced HCC between January 2008 – January 2012 was performed. Diagnosis of HCC was by AASLD criteria and patients must have at least one follow-up scan in our institution. Excluded were: tumour in the contralateral lobe, concomitant other treatment for HCC, patients enrolled in clinical trials. Pre- and post-treatment images were reviewed and volumes were measured using 3D software. Statistical analysis was conducted using SPSS version 16.0. Results: During this period 50 patients treated with Y90 for HCC had follow-up imaging at our institution. Of 37 patients with right-sided Y90 treatment, 11 had concomitant left-sided disease treated with TACE and RFA, 7 had follow-up scans of inadequate quality to perform accurate volumetric assessment, 2 had pre-treatment scans performed at another institution which were not accessible for study purposes. Seventeen (17) patients thus fulfilled criteria. Mean and median left-lobe hypertrophy were 34.2% (SD±35.9%) and 31.7% (range -19.0 – 106.5%) respectively at a median of 5 months post-treatment. Univariate analysis identified no specific pre-treatment factor predictive of the degree of left lobe hypertrophy. There were no cases of acute liver failure after administration of SIRT in this study and none of the patients developed disease in the contralateral lobe over the study period. Conclusions: In patients with HCC receiving SIRT to the right lobe via the right hepatic artery, a significant degree of left lobe hypertrophy results. This opens the possibility of the utilisation of SIRT as neoadjuvant therapy for borderline resectable HCC, thus increasing the pool of potentially operable and curable patients.

Male Breast Cancer in Singapore: 15 Years of Experience at a Single Tertiary Institution

Introduction: Male breast cancer is a rare disease entity, with little data from the Southeast Asian perspective. Hence, this study aims to review the data from our local experience in order to better delineate the disease characteristics in our population. Materials and Methods: Male patients with histologically proven breast cancer were identified from a prospectively collected database. The clinical, histopathological and survival data were reviewed retrospectively and analysed. Results: Twenty-one patients were identified. The median age at diagnosis was 68 years. Eighteen patients underwent simple mastectomy with curative intent, with the remaining patients having metastatic disease at presentation. Almost half of the patients presented with stage III or IV disease. At the time of analysis, median overall survival was 50 months and median disease-free survival was 47.5 months. None of the patients had any documented family history or risk factors for male breast cancer. Conclusion: The disease appears to be a sporadic and rare occurrence in the local male population. A high index of suspicion should be maintained in males presented with a unilateral breast lump so that appropriate treatment can be instituted. Key words: Asian, Clinical characteristics, Prognosis, Treatment

Male breast cancer in Singapore: 15 years of experience at a single tertiary institution

INTRODUCTION

Male breast cancer is a rare disease entity, with little data from the Southeast Asian perspective. Hence, this study aims to review the data from our local experience in order to better delineate the disease characteristics in our population.

MATERIALS AND METHODS

Male patients with histologically proven breast cancer were identified from a prospectively collected database. The clinical, histopathological and survival data were reviewed retrospectively and analysed.

RESULTS

Twenty-one patients were identified. The median age at diagnosis was 68 years. Eighteen patients underwent simple mastectomy with curative intent, with the remaining patients having metastatic disease at presentation. Almost half of the patients presented with stage III or IV disease. At the time of analysis, median overall survival was 50 months and median disease-free survival was 47.5 months. None of the patients had any documented family history or risk factors for male breast cancer.

CONCLUSION

The disease appears to be a sporadic and rare occurrence in the local male population. A high index of suspicion should be maintained in males presented with a unilateral breast lump so that appropriate treatment can be instituted.

Colonic perforation caused by direct trauma during computed tomographic colonography performed via end colostomy

We report the case of a woman with a history of abdominoperineal resection for cancer, who had an inadvertent perforation during screening computed tomographic colonography performed via end colostomy. Revision of the stoma was promptly performed, which prevented a full laparotomy. We reviewed the literature on the subject and found that such perforations may be more common than previously thought. With appropriate precautions, such occurrences can be minimised in the future.