Oncological Outcomes of Major Liver Resection Following Portal Vein Embolization: A Systematic Review and Meta-analysis

Future liver remnant hypertrophy and postoperative outcomes: a retrospective comparison between segmental and main right portal vein embolization

OBJECTIVE

To assess the efficacy of segmental right portal vein embolization (SRPVE) versus main right portal vein embolization (MRPVE) in preoperative preparation for major hepatectomy.

METHODS

This retrospective single-center study included 220 consecutive patients who underwent portal vein embolization (PVE) before (extended) right hemihepatectomy between January 2014 and June 2021. Seventy-one patients underwent selective segmental embolization (SRPVE) and 149 patients underwent MRPVE. Volumetric analysis was conducted before PVE and before surgery. Key endpoints included evaluation of future liver remnant (FLR) hypertrophy, intraoperative complexity, and postoperative complications, technical success, clinical success, complications (Clavien-Dindo and CIRSE classifications), as well as evaluation of different factors which may influence hypertrophy of the FLR.

RESULTS

Technical success rate was 100% in the SRPVE group and 99.3% in the MRPVE group (p = 0.15). Clinical success rate was comparable between both techniques, measuring 95.8% in the SRPVE group and 95.3% in the MRPVE group (p = 0.18). Absolute hypertrophy (FLRabh) of the FLR was comparable between both techniques, measuring 47.15% in the SRPVE group and 40.78% in the MRPVE group (p = 0.54). Complication rates did not differ significantly (p = 0.12). Partial thrombosis involving the left portal vein, main portal vein, or mesentericosplenic region was observed in 2.8% of the patients in the SRPVE group vs 3.4% in the MRPVE group (p = 0.95). CIRSE Class II-VI complications were slightly higher in the MRPVE group (10.7% vs 9.8%, p = 0.82). Postoperative complications with Clavien-Dindo class ≥ IIIa occurred in 10.1% % in the MRPVE group vs 9.9% the SRPVE group (p = 0.92). Liver cirrhosis had a significant negative correlation with sFLR % increase following PVE (r = -0.54; p = 0.027). Neoadjuvant chemotherapy was also associated with reduced FLR hypertrophy following PVE, with a median sFLR% change of 63.8% (IQR: 60.8% - 75.2%) in patients who received neoadjuvant chemotherapy (n = 66 patients, 30%) compared to 82.6% (IQR: 77.4% - 84.2%) in those without chemotherapy (n = 154 patients, 70%).

CONCLUSION

Selective segmental right portal vein embolization, sparing the main right portal vein, offers a safe and effective alternative to MRPVE, achieving comparable FLR hypertrophy while potentially simplifying intraoperative procedures and reducing postprocedural complications. Future research should focus on conducting large, prospective, multicenter trials to further compare the long-term outcomes of this technique, particularly with regard to liver regeneration, postoperative liver function, complications and overall survival.

Initial experience with Double-vein Embolization in Hungary

Introduction

In recent years several new techniques have emerged to induce hypertrophy of the future liver remnant prior to major hepatectomies. We aimed to summarize our initial experience with Double-vein Embolization as the first center in Hungary.

Methods

Between March 2023 and August 2024 a total of 16 Double-vein Embolization procedures were performed in Semmelweis University. Future liver remnant volume was calculated based on computed tomography scans obtained within 4 weeks prior and 2-3 weeks after the procedure. Tc-99m mebrofenin hepatobiliary scintigraphy results were available for 12/16 patients.

Results

Technical success rate was 100 %. No major complication was observed. Successful resection rate was 93.8 %. One patient died due to post-hepatectomy liver failure. Future liver remnant volume and ratio increased significantly after the procedure compared to baseline (433.1 ± 163.8 cm3 vs. 603.5 ± 201.8 cm3, p < 0.0001 and 27.2 ± 6.5 % vs. 37 ± 8.8 %, p < 0.0001, respectively). Future liver remnant clearance improved significantly 1 and 2 weeks after the procedure (1.68 ± 0.58 %/min/m2 vs. 2.44 ± 0.64 %/min/m2 and 2.39 ± 0.31 %/min/m2, respectively). Mean function gain was 50.6 % after one week and 60.1% after two weeks, respectively.

Discussion

Volumetric and functional outcomes in the present study are comparable with results reported in the literature. Our findings provide further evidence that Double-vein Embolization is a safe procedure that offers sufficient volumetric and functional gain in most candidates for liver resection. However, further studies are needed to define the exact place of this new technique in clinical practice.

Comprehensive Review of Future Liver Remnant (FLR) Assessment and Hypertrophy Techniques Before Major Hepatectomy: How to Assess and Manage the FLR

BACKGROUND

The regenerative capacities of the liver and improvements in surgical techniques have expanded the possibilities of resectability. Liver resection is often the only curative treatment for primary and secondary malignancies, despite the risk of post-hepatectomy liver failure (PHLF). This serious complication (with a 50% mortality rate) can be avoided by better assessment of liver volume and function of the future liver remnant (FLR).

OBJECTIVE

The aim of this review was to understand and assess clinical, biological, and imaging predictors of PHLF risk, as well as the various hypertrophy techniques, to achieve an adequate FLR before hepatectomy.

METHOD

We reviewed the state of the art in liver regeneration and FLR hypertrophy techniques.

RESULTS

The use of new biological scores (such as the aspartate aminotransferase/platelet ratio index + albumin-bilirubin [APRI+ALBI] score), concurrent utilization of 99mTc-mebrofenin scintigraphy (HBS), or dynamic hepatocyte contrast-enhanced MRI (DHCE-MRI) for liver volumetry helps predict the risk of PHLF. Besides portal vein embolization, there are other FLR optimization techniques that have their indications in case of risk of failure (e.g., associating liver partition and portal vein ligation for staged hepatectomy, liver venous deprivation) or in specific situations (transarterial radioembolization).

CONCLUSION

There is a need to standardize volumetry and function measurement techniques, as well as FLR hypertrophy techniques, to limit the risk of PHLF.

CIRSE Standards of Practice on Portal Vein Embolization and Double Vein Embolization/Liver Venous Deprivation

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing liver regeneration therapies prior to major hepatectomies, including portal vein embolization, double vein embolization and liver venous deprivation. It has been developed by an expert writing group under the guidance of the CIRSE Standards of Practice Committee. It encompasses all clinical and technical details required to perform liver regeneration therapies, revising the indications, contra-indications, outcome measures assessed, technique and expected outcomes.

IL-22 promotes liver regeneration after portal vein ligation

Background

Insufficient remnant liver volume (RLV) after the resection of hepatic malignancy could lead to liver failure and mortality. Portal vein ligation (PVL) prior to hepatectomy is subsequently introduced to increase the remnant liver volume and improve the outcome of hepatic malignancy. IL-22 has previously been reported to promote liver regeneration, while facilitating tumor development in the liver via Steap4 upregulation. Here we performed PVL in mouse models to study the role of IL-22 in liver regeneration post-PVL.

Methods

Liver weight and volume was measured via magnetic resonance imaging (MRI). Immunohistochemistry for Ki67 and hepatocyte growth factor (HGF) was performed. IL-22 was analyzed by flow cytometry and quantitative polymerase chain reaction (qPCR) was used for acquisition of Il-33, Steap4, Fga, Fgb and Cebpd. To analyze signaling pathways, mice with deletion of STAT3 and a neutralizing antibody for IL-22 were used.

Results

The remnant liver weight and volume increased over time after PVL. Additionally, we found that liver regenerative molecules, including Ki67 and HGF, were significantly increased in remnant liver at day 3 post-PVL, as well as IL-22. Administration of IL-22 neutralizing antibody could reduce Ki67 expression after PVL. The upregulation of IL-22 after PVL was mainly derived from innate cells. IL-22 blockade resulted in lower levels of IL-33 and Steap4 in the remnant liver, which was also the case in mice with deletion of STAT3, the main downstream signaling molecule of IL-22, in hepatocytes.

Conclusion

IL-22 promotes liver regeneration after PVL. Thus, a combination of IL-22 supplementation and Steap4 blockade could potentially be applied as a novel therapeutic approach to boost liver regeneration without facilitating tumor progression after PVL.

The role of ischaemia-reperfusion injury and liver regeneration in hepatic tumour recurrence

The risk of cancer recurrence after liver surgery mainly depends on tumour biology, but preclinical and clinical evidence suggests that the degree of perioperative liver injury plays a role in creating a favourable microenvironment for tumour cell engraftment or proliferation of dormant micro-metastases. Understanding the contribution of perioperative liver injury to tumour recurrence is imperative, as these pathways are potentially actionable. In this review, we examine the key mechanisms of perioperative liver injury, which comprise mechanical handling and surgical stress, ischaemia-reperfusion injury, and parenchymal loss leading to liver regeneration. We explore how these processes can trigger downstream cascades leading to the activation of the immune system and the pro-inflammatory response, cellular proliferation, angiogenesis, anti-apoptotic signals, and release of circulating tumour cells. Finally, we discuss the novel therapies under investigation to decrease ischaemia-reperfusion injury and increase regeneration after liver surgery, including pharmaceutical agents, inflow modulation, and machine perfusion.

Interventional radiological therapies in colorectal hepatic metastases

Colorectal malignancy is the third most common cancer and one of the prevalent causes of death globally. Around 20-25% of patients present with metastases at the time of diagnosis, and 50-60% of patients develop metastases in due course of the disease. Liver, followed by lung and lymph nodes, are the most common sites of colorectal cancer metastases. In such patients, the 5-year survival rate is approximately 19.2%. Although surgical resection is the primary mode of managing colorectal cancer metastases, only 10-25% of patients are competent for curative therapy. Hepatic insufficiency may be the aftermath of extensive surgical hepatectomy. Hence formal assessment of future liver remnant volume (FLR) is imperative prior to surgery to prevent hepatic failure. The evolution of minimally invasive interventional radiological techniques has enhanced the treatment algorithm of patients with colorectal cancer metastases. Studies have demonstrated that these techniques may address the limitations of curative resection, such as insufficient FLR, bi-lobar disease, and patients at higher risk for surgery. This review focuses on curative and palliative role through procedures including portal vein embolization, radioembolization, and ablation. Alongside, we deliberate various studies on conventional chemoembolization and chemoembolization with irinotecan-loaded drug-eluting beads. The radioembolization with Yttrium-90 microspheres has evolved as salvage therapy in surgically unresectable and chemo-resistant metastases.

Liver Venous Deprivation Versus Portal Vein Embolization Before Major Hepatectomy for Colorectal Liver Metastases: A Retrospective Comparison of Short- and Medium-Term Outcomes

BACKGROUND

Liver venous deprivation (LVD) is a recent radiological technique performed to induce hypertrophy of the future liver remnant. Medium-term results of major hepatectomy after LVD have never been compared with the actual standard of care, portal vein embolization (PVE).

METHODS

We retrospectively compared data from 33 consecutive patients who had undergone LVD (n = 17) or PVE (n = 16) prior to a right hemi-hepatectomy or right extended hepatectomy indicated for colorectal liver metastases (CRLM) between May 2015 and December 2019.

RESULTS

The 1-year and 3-year overall survival (OS) rates in the LVD group were 81.3% (95% confidence interval [CI]: 72-90) and 54.7% (95% CI: 46-63), respectively, against 85% (95% CI: 69-101) and 77.4% (95% CI: 54-100) in the PVE group; the differences were not statistically significant (p = 0.64). The median disease-free survival (DFS) rate was also comparable: 6 months (95% CI: 4-7) in the LVD group and 12 months (95% CI: 1.5-13) in the PVE group (p = 0.29). The overall intra-operative and post-operative complication rates were similar between the two groups. The mean daily kinetic growth rate (KGR) was found to be higher after LVD than after PVE (0.2% vs. 0.1%, p = 0.05; 10 cc/day vs. 4.8 cc/day, p = 0.03), as was the mean increase in future liver remnant volume (FLR-V) (49% vs. 27%, p = 0.01).

CONCLUSIONS

The LVD technique is well tolerated in patients undergoing right hemi-hepatectomy or right extended hepatectomy for CRLM. When compared with the PVE technique, the LVD technique has similar peri-operative and medium-term outcomes, but higher KGR and FLR-V increase.

Portal Vein Embolization: Rationale, Techniques, and Outcomes to Maximize Remnant Liver Hypertrophy with a Focus on Contemporary Strategies

Hepatectomy remains the gold standard for curative therapy for patients with limited primary or metastatic hepatic tumors as it offers the best survival rates. In recent years, the indication for partial hepatectomy has evolved away from what will be removed from the patient to the volume and function of the future liver remnant (FLR), i.e., what will remain. With this regard, liver regeneration strategies have become paramount in transforming patients who previously had poor prognoses into ones who, after major hepatic resection with negative margins, have had their risk of post-hepatectomy liver failure minimized. Preoperative portal vein embolization (PVE) via the purposeful occlusion of select portal vein branches to promote contralateral hepatic lobar hypertrophy has become the accepted standard for liver regeneration. Advances in embolic materials, selection of treatment approaches, and PVE with hepatic venous deprivation or concurrent transcatheter arterial embolization/radioembolization are all active areas of research. To date, the optimal combination of embolic material to maximize FLR growth is not yet known. Knowledge of hepatic segmentation and portal venous anatomy is essential before performing PVE. In addition, the indications for PVE, the methods for assessing hepatic lobar hypertrophy, and the possible complications of PVE need to be fully understood before undertaking the procedure. The goal of this article is to discuss the rationale, indications, techniques, and outcomes of PVE before major hepatectomy.

Volume and flow modulation strategies to mitigate post-hepatectomy liver failure

INTRODUCTION

Post hepatectomy liver failure is the most common cause of death following major hepatic resections with a perioperative mortality rate between 40% to 60%. Various strategies have been devised to increase the volume and function of future liver remnant (FLR). This study aims to review the strategies used for volume and flow modulation to reduce the incidence of post hepatectomy liver failure.

METHOD

An electronic search was performed of the MEDLINE, EMBASE and PubMed databases from 2000 to 2022 using the following search strategy "Post hepatectomy liver failure", "flow modulation", "small for size flow syndrome", "portal vein embolization", "dual vein embolization", "ALPPS" and "staged hepatectomy" to identify all articles published relating to this topic.

RESULTS

Volume and flow modulation strategies have evolved over time to maximize the volume and function of FLR to mitigate the risk of PHLF. Portal vein with or without hepatic vein embolization/ligation, ALPPS, and staged hepatectomy have resulted in significant hypertrophy and kinetic growth of FLR. Similarly, techniques including portal flow diversion, splenic artery ligation, splenectomy and pharmacological agents like somatostatin and terlipressin are employed to reduce the risk of small for size flow syndrome SFSF syndrome by decreasing portal venous flow and increasing hepatic artery flow at the same time.

CONCLUSION

The current review outlines the various strategies of volume and flow modulation that can be used in isolation or combination in the management of patients at risk of PHLF.

Portal vein embolization failure: Current strategies and future perspectives to improve liver hypertrophy before major oncological liver resection

Portal vein embolization (PVE) is currently considered the standard of care to improve the volume of an inadequate future remnant liver (FRL) and decrease the risk of post-hepatectomy liver failure (PHLF). PHLF remains a significant limitation in performing major liver surgery and is the main cause of mortality after resection. The degree of hypertrophy obtained after PVE is variable and depends on multiple factors. Up to 20% of patients fail to undergo the planned surgery because of either an inadequate FRL growth or tumor progression after the PVE procedure (usually 6-8 wk are needed before surgery). The management of PVE failure is still debated, with a lack of consensus regarding the best clinical strategy. Different additional techniques have been proposed, such as sequential transarterial chemoembolization followed by PVE, segment 4 PVE, intra-portal administration of stem cells, dietary supplementation, and hepatic vein embolization. The aim of this review is to summarize the up-to-date strategies to overcome such difficult situations and discuss future perspectives on improving FRL hypertrophy.

Future remnant liver optimization: preoperative assessment, volume augmentation procedures and management of PVE failure

Surgery is the cornerstone treatment for patients with primary or metastatic hepatic tumors. Thanks to surgical and anesthetic technological advances, current indications for liver resections have been significantly expanded to include any patient in whom all disease can be resected with a negative margin (R0) while preserving an adequate future residual liver (FRL). Posthepatectomy liver failure (PHLF) is still a feared complication following major liver surgery, associated with high morbidity, mortality and cost implications. PHLF is mainly linked to both the size and quality of the FRL. Significant advances have been made in detailed preoperative assessment to predict and mitigate this complication, even if an ideal methodology has yet to be defined. Several procedures have been described to induce hypertrophy of the FRL when needed. Each technique has its advantages and limitations, and among them portal vein embolization (PVE) is still considered the standard of care. About 20% of patients after PVE fail to undergo the scheduled hepatectomy, and newer secondary procedures, such as segment 4 embolization, ALPPS and HVE, have been proposed as salvage strategies. The aim of this review was to discuss the current modalities available and new perspectives in the optimization of FRL in patients undergoing major liver resection.

Bile leak incidence, risk factors and associated outcomes in patients undergoing hepatectomy: a contemporary NSQIP propensity matched analysis

BACKGROUND

Despite advances in surgical technique, bile leak remains a common complication following hepatectomy. We sought to identify incidence of, risk factors for, and outcomes associated with biliary leak.

STUDY DESIGN

This is an ACS-NSQIP study. Distribution of bile leak stratified by surgical approach and hepatectomy type were identified. Univariate and multivariate factors associated with bile leak and outcomes were evaluated.

RESULTS

Robotic hepatectomy was associated with less bile leak (5.4% vs. 11.4%; p < 0.001) compared to open. There were no significant differences in bile leak between robotic and laparoscopic hepatectomy (5.4% vs. 5.3%; p = 0.905, respectively). Operative factors risk factors for bile leak in patients undergoing robotic hepatectomy included right hepatectomy [OR 4.42 (95% CI 1.74-11.20); p = 0.002], conversion [OR 4.40 (95% CI 1.39-11.72); p = 0.010], pringle maneuver [OR 3.19 (95% CI 1.03-9.88); p = 0.044], and drain placement [OR 28.25 (95% CI 8.34-95.72); p < 0.001]. Bile leak was associated with increased reoperation (8.7% vs 1.7%, p < 0.001), 30-day readmission (26.6% vs 6.8%, p < 0.001), 30-day mortality (2% vs 0.9%, p < 0.001), and complications (67.2% vs 23.4%, p < 0.001) for patients undergoing MIS hepatectomy.

CONCLUSION

While MIS confers less risk for bile leak than open hepatectomy, risk factors for bile leak in patients undergoing MIS hepatectomy were identified. Bile leaks were associated with multiple additional complications, and the robotic approach had an equal risk for bile leak than laparoscopic in this time period.

Imaging-guided interventions modulating portal venous flow: evidence and controversies

Portal hypertension is defined by an increase in the portosystemic venous gradient. In most cases, increased resistance to portal blood flow is the initial cause of elevated portal pressure. More than 90% of cases of portal hypertension are estimated to be due to advanced chronic liver disease or cirrhosis. Transjugular intrahepatic portosystemic shunts, a non-pharmacological treatment for portal hypertension, involve the placement of a stent between the portal vein and the hepatic vein or inferior vena cava which helps bypass hepatic resistance. Portal hypertension may also be a result of extrahepatic portal vein thrombosis or compression. In these cases, percutaneous portal vein recanalisation restores portal trunk patency, thus preventing portal hypertension-related complications. Any portal blood flow impairment leads to progressive parenchymal atrophy and triggers hepatic regeneration in preserved areas. This provides the rationale for using portal vein embolisation to modulate hepatic volume in preparation for extended hepatic resection. The aim of this paper is to provide a comprehensive evidence-based review of the rationale for, and outcomes associated with, the main imaging-guided interventions targeting the portal vein, as well as to discuss the main controversies around such approaches.

Portal vein embolization: rationale, techniques, outcomes and novel strategies

The incidence of liver cancer has grown in the past decade, with 905,677 new cases and 830,180 deaths in 2020. According to the highest annual fatality ratio, liver cancer is the third-leading cause of cancer-related deaths worldwide. Surgical resection is the mainstay treatment for long-term survival. However, only 25% of patients are surgical candidates. Recent surgical concepts, techniques and multidisciplinary management were developed, including interventional radiology procedures that improve the management algorithm, expand the indications and limit dropouts from curative treatment. This review summarizes up-to-date information on interventional radiology in the management of liver tumors.

A novel online calculator based on noninvasive markers (ALBI and APRI) for predicting post-hepatectomy liver failure in patients with hepatocellular carcinoma

BACKGROUND AND AIM

Post-hepatectomy liver failure (PHLF) remains the primary cause of in-hospital mortality after hepatectomy. Identifying predictors of PHLF is important to improve surgical safety. We sought to identify the predictive accuracy of two noninvasive markers, albumin-bilirubin (ALBI) and aspartate aminotransferase to platelet count ratio index (APRI), to predict PHLF among patients with hepatocellular carcinoma (HCC), and to build up an online prediction calculator.

METHODS

Patients who underwent resection for HCC between 2013 and 2016 at 6 Chinese hospitals were retrospectively analyzed. The independent predictors of PHLF were identified using univariate and multivariate analyses; derivative data were used to construct preoperative and postoperative nomogram models. Receiver operating characteristic (ROC) curves for the two predictive models, and ALBI, APRI, Child-Pugh, model for end-stage liver disease (MELD) scores were compared relative to predictive accuracy for PHLF.

RESULTS

Among the 767 patients in the analytic cohort, 102 (13.3%) experienced PHLF. Multivariable logistic regression analysis identified high ALBI grade (>-2.6) and high APRI grade (>1.5) as independent risk factors associated with PHLF in both the preoperative and postoperative models. Two nomogram predictive models and corresponding web-based calculators were subsequently constructed. The areas under the ROC curves for the postoperative and preoperative models, APRI, ALBI, MELD and Child-Pugh scores in predicting PHLF were 0.844, 0.789, 0.626, 0.609, 0.569, and 0.560, respectively.

CONCLUSIONS

ALBI and APRI demonstrated more accurate ability to predict PHLF than Child-Pugh and MELD. Two online calculators that combined ALBI and APRI were proposed as useful preoperative and postoperative tools for individually predicting the occurrence of PHLF among patients with HCC.

Liver regeneration and liver metastasis

Surgical resection for primary and secondary hepatic neoplasms provides the best chance of cure. Advanced surgical techniques such as portal vein embolisation, two-staged hepatectomy and associated liver partition and portal vein ligation for staged-hepatectomy (ALPPS) have facilitated hepatic resection in patients with previously unresectable, bi-lobar disease. These techniques are frequently employed to ensure favourable clinical outcomes and avoid potentially fatal post-operative complications such as small for size syndrome and post-hepatectomy liver failure. However, they rely on the innate ability of the liver to regenerate. As our knowledge of liver organogenesis, liver regeneration and hepatocarcinogenesis has expanded in recent decades it has come to light that liver regeneration may also drive tumour recurrence. Clinical studies in patients undergoing portal vein embolisation indicate that tumours may progress following the procedure in concordance with liver regeneration and hypertrophy, however overall survival in these patients has not been shown to be worse. In this article, we delve into the mechanisms underlying liver regeneration to better understand the complex ways in which this may affect tumour behaviour and ultimately inform clinical decisions.

Oncological Outcomes after Liver Venous Deprivation for Colorectal Liver Metastases: A Single Center Experience

Colorectal liver metastases (CRLM) are the major cause of death in patients with colorectal cancer (CRC). The cornerstone treatment of CRLM is surgical resection. Post-operative morbidity and mortality are mainly linked to an inadequate future liver remnant (FLR). Nowadays preoperative portal vein embolization (PVE) is the most widely performed technique to increase the size of the future liver remnant (FLR) before major hepatectomies. One method recently proposed to increase the FLR is liver venous deprivation (LVD), but its oncological impact is still unknown. The aim of this study is to report first short- and long-term oncological outcomes after LVD in patients undergoing right (or extended right) hepatectomy for CRLM. Seventeen consecutive patients undergoing LVD between July 2015 and May 2020 before an (extended) right hepatectomy were retrospectively analyzed from an institutional database. Post-operative and follow-up data were analyzed and reported. Primary outcomes were 1-year and 3-year overall survival (OS) and hepatic recurrence (HR). Postoperative complications occurred in 8 patients (47%). No deaths occurred after surgery. HR occurred in 9 patients (52.9%). 1-year and 3-year OS were 87% (95% confidence interval [CI]: ±16%) and 60.3%, respectively (95% CI: ±23%). Median Disease-Free Survival (DFS) was 6 months (CI 95%: 4.7-7.2). With all the limitations of a retrospective study with a small sample size, LVD showed similar oncological outcomes compared to literature reports for Portal Vein Embolization (PVE).

The actual management of colorectal liver metastases

Colorectal cancer is one of the most frequent cancers in the world and between 50% and 60% of patients will develop colorectal liver metastases (CRLM) during the disease. There have been great improvements in the management of CRLM during the last decades. The combination of modern chemotherapeutic and biological systemic treatments with aggressive surgical resection strategies is currently the base for the treatment of patients considered unresectable until few years ago. Furthermore, several new treatments for the local control of CRLM have been developed and are now part of the arsenal of multidisciplinary teams for the treatment of these complex patients. The aim of this review was to summarize and update the management of CRLM, its controversies and relevant evidence.

Preoperative Portal Vein Embolization Is Not Associated with Increased Postoperative Complications After Major Hepatectomy: a Study of the National Surgical Quality Improvement Database

BACKGROUND

Preoperative portal vein embolization (PVE) is selectively performed to induce hypertrophy of the future liver remnant prior to major liver resection. The primary aim of this study was to determine the association of PVE with liver-specific and overall postoperative morbidity.

METHODS

A retrospective cohort study of patients who underwent major hepatectomy from 2014 to 2016 within the ACS-NSQIP hepatectomy-specific module was performed.

RESULTS

Of the 3912 patients identified, 9.9% (N = 388) underwent PVE. Patients who underwent PVE were older (59.1 vs. 57.7 years). Most patients in the PVE cohort underwent right hepatectomy (51.8%, N = 201) or trisectionectomy (46.1%, N = 179), compared with right (49.3%, N = 1738) and left hepatectomy (29.6%, N = 1042) in the non-PVE cohort (p < 0.001). Median operative time was longer in the PVE group (310 vs. 276 min, p < 0.001). Post-hepatectomy liver failure was more common among patients undergoing PVE (18.6% (N = 72) vs. 9.9% (N = 350), p < 0.001), as was bile leak (17.3% (N = 67) vs. 12.2% (N = 428), p = 0.005). Overall complication rates were higher among patients who underwent PVE (45.9% (N = 178) vs. 34.0% (N = 1199), p < 0.001). However, on multivariable analysis controlling for patient and technical factors, PVE remained associated with an increased risk of liver-specific complications (OR 1.33, 95% CI 1.01-1.74) but not with overall complications (OR 1.17, 95% CI 0.92-1.50).

CONCLUSION

Within a national cohort, patients treated with PVE are older and undergo a more extensive liver resection. When controlling for patient and technical factors, PVE is neither associated with an increase in overall morbidity nor mortality, suggesting that PVE can be safely used in appropriate patients undergoing major hepatectomy.

How to increase the resectability of initially unresectable colorectal liver metastases: A surgical perspective

Although surgical resection is the only treatment of choice that can offer prolonged survival and a chance of cure in patients with colorectal liver metastases (CRLM), nearly 80% of patients are deemed to be unresectable at the time of diagnosis. Considerable efforts have been made to overcome this initial unresectability, including expanding the indication of surgery, the advent of conversion chemotherapy, and development and modification of specific surgical techniques, regulated under multidisciplinary approaches. In terms of specific surgical techniques, portal vein ligation/embolization can increase the volume of future liver remnant and thereby reduce the risk of hepatic insufficiency and death after major hepatectomy. For multiple bilobar CRLM that were traditionally considered unresectable even with preoperative chemotherapy and portal vein embolization, two-stage hepatectomy was introduced and has been adopted worldwide with acceptable short- and long-term outcomes. Recently, ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) was reported as a novel variant of two-stage hepatectomy. Although issues regarding safety remain unresolved, rapid future liver remnant hypertrophy and subsequent shorter intervals between the two stages lead to a higher feasibility rate, reaching 98%. In addition, adding radiofrequency ablation and vascular resection and reconstruction techniques can allow expansion of the pool of patients with CRLM who are candidates for liver resection and thus a cure. In this review, we discuss specific techniques that may expand the criteria for resectability in patients with initially unresectable CRLM.

The incidence and severity of post-hepatectomy bile leaks is affected by surgical indications, preoperative chemotherapy, and surgical procedures

Background

Bile leaks are one of the most common complications after liver resection. The International Study Group of Liver Surgery (ISGLS) established a uniform bile leak definition including a severity grading. However, a risk factor assessment according to ISGLS grading as well as the clinical implications has not been studied sufficiently so far.

Methods

The incidence and grading of bile leaks according to ISGLS were prospectively documented in 501 consecutive liver resections between July 2012 and December 2016. A multivariate regression analysis was performed for risk factor assessment. Association with other surgical complications, 90-day mortality as well as length of hospital stay (LOS) was studied.

Results

The total rate of bile leaks in this cohort was 14.0%: 2.8% grade A, 8.0% grade B, and 3.2% grade C bile leaks were observed. Preoperative chemotherapy or biliary intervention, diagnosis of hilar cholangiocarcinoma, colorectal metastasis, central minor liver resection, major hepatectomy, extended hepatectomy or two-stage hepatectomy, were some of the risk factors leading to bile leaks. The multivariate regression analysis revealed that preoperative chemotherapy, major hepatectomy and biliodigestive reconstruction remained significant independent risk factors for bile leaks. Grade C bile leaks were associated not only with surgical site infection, but also with an increased 90-day mortality and prolonged LOS.

Conclusions

The preoperative treatment as well as the surgical procedure had significant influence on the incidence and the severity of bile leaks. Grade C bile leaks were clinically most relevant, and led to significant increased LOS, rate of infection, and mortality.

Colorectal liver metastases: An update on multidisciplinary approach

Liver metastasis is the commonest form of distant metastasis in colorectal cancer. Selection criteria for surgery and liver-directed therapies have recently been extended. However, resectability remains poorly defined. Tumour biology is increasingly recognized as an important prognostic factor; hence molecular profiling has a growing role in risk stratification and management planning. Surgical resection is the only treatment modality for curative intent. The most appropriate surgical approach is yet to be established. The primary cancer and the hepatic metastasis can be removed simultaneously or in a two-step approach; these two strategies have comparable long-term outcomes. For patients with a limited future liver remnant, portal vein embolization, combined ablation and resection, and associating liver partition and portal vein ligation for staged hepatectomy have been advocated, and each has their pros and cons. The role of neoadjuvant and adjuvant chemotherapy is still debated. Targeted biological agents and loco-regional therapies (thermal ablation, intra-arterial chemo- or radio-embolization, and stereotactic radiotherapy) further improve the already favourable results. The recent debate about offering liver transplantation to highly selected patients needs validation from large clinical trials. Evidence-based protocols are missing, and therefore optimal management of hepatic metastasis should be personalized and determined by a multi-disciplinary team.

Segment 2/3 Hypertrophy is Greater When Right Portal Vein Embolisation is Extended to Segment 4 in Patients with Colorectal Liver Metastases: A Retrospective Cohort Study

Background

In patients with colorectal cancer liver metastases (CRLM), right portal vein embolisation (RPVE) is used to increase the volume of the future remnant liver (FRL) before major hepatic resection. It is not established whether embolisation of segment 4 in addition RPVE (RPVE + 4) induces greater hypertrophy of the FRL. Limitations of prior studies include heterogenous populations and use of hypertrophy metrics sensitive to baseline variables.

Methods

From 2010 to 2015, consecutive patients undergoing RPVE or RPVE + 4 for CRLM, who had not undergone prior major hepatic resection and in whom imaging was available, were included in a retrospective study. Data were extracted from hospital electronic records. Volumetric assessments of segments 2–3 were made on cross-sectional imaging before and after embolisation and corrected for standardised liver volume.

Results

Ninety-nine patients underwent PVE, and 60 met the inclusion criteria. Thirty-eight patients underwent RPVE, and 22 underwent RPVE + 4. Forty-five patients had undergone median 6 cycles of prior chemotherapy. Eighteen patients had FRL metastases at PVE, and 16 had undergone subsegmental metastasectomy in the FRL. Assessments of the degree of hypertrophy (DH) of segments 2/3 were made at median 35 (interquartile range 30–49) days after PVE. RPVE + 4 resulted in a significantly greater increase in DH than RPVE (7.7 ± 1.8% vs 11.3 ± 2.6%, p = 0.011). No confounding association between baseline variables and the decision to undertake RPVE or RPVE + 4 was identified. Median survival was 2.4 years and was not influenced by segment 4 embolisation.

Conclusion

RPVE + 4 results in greater DH of segments 2/3 than RPVE in people with CLRM.

Portal vein embolization does not affect the long-term survival and risk of cancer recurrence among colorectal liver metastases patients: A prospective cohort study

BACKGROUND

Previous studies comparing the survival outcomes of liver resections with and without preoperative portal vein embolization (PVE) for colorectal liver metastases (CLM) have linked PVE to higher rate of tumor progression, lower overall survival (OS) and lower disease-free survival (DFS). The lack of adjusted models to compare these outcomes is a limitation of these studies since patients requiring PVE may differ significantly from the ones receiving upfront surgery.

MATERIALS AND METHODS

Prospective cohort study of 128 patients undergoing CLM resection. The OS analysis followed an intent-to-treat (ITT) approach. The adjusted impact of PVE on OS and DFS was evaluated using multivariate Cox regression models.

RESULTS

Seventy-one patients underwent PVE before attempting a liver resection while 57 received upfront surgery (NoPVE). All NoPVE patients were resected while 14 PVE participants (19.7%) were not operated (tumor progression = 9/14). PVE patients had a significantly higher preoperative lesions count (3 [1.75-4] vs 1 [1-2.5]; p < 0.001), a higher prevalence of bilateral metastases (23.5% vs 8.8, p = 0.028) and a higher count of neo-adjuvant chemotherapy cycles compared to NoPVE patients. The OS of PVE patients was similar to NoPVE participants (44.7 months [26.9-69.5] vs 49.0 [24.9-64.8], p = 0.761). The DFS of resected PVE patients was higher than NoPVE patients (33.2 months [10.7-54.6] vs 23.4 months [14.1-58.1], p = 0.991). In the adjusted models, preoperative lesions count was the only significant predictor of overall mortality (HR+IC₉₅ = 1.06 (1.02-1.11) p = 0.005) and cancer recurrence (HR+IC₉₅ = 1.14 (1.03-1.27) p = 0.012).

CONCLUSION

In the context of CLM, patients requiring PVE differ significantly from patients receiving upfront surgery. This confirms the need for adjusted models when comparing the clinical outcomes of both groups. Our adjusted analysis suggests that PVE is not a significant predictor of a lower OS or DFS. PVE allowed the resection of 80% of participants with initially unresectable CLM.

INSTITUTIONAL PROTOCOL NUMBER

12.106 STUDY REGISTRATION NUMBER: NCT03168230.

Is disease progression a contraindication for the strategy of portal vein embolization followed by hepatectomy for hepatocellular carcinoma?

BACKGROUND

Portal vein embolization has been used worldwide to induce hypertrophy of the future liver remnant and to reduce the risk of hepatic insufficiency and death after major hepatectomy. However, whether disease progression after portal vein embolization can affect long-term oncologic outcomes in patients with hepatocellular carcinoma is uncertain.

METHODS

From a total of 107 patients who underwent portal vein embolization and subsequent hepatectomy between 2000 and 2016, 57 patients with hepatocellular carcinoma were enrolled. We evaluated their long-term oncologic outcomes and investigated whether the disease progression between portal vein embolization and subsequent hepatectomy affected survival.

RESULTS

The 5-year overall survival and disease-free survival after hepatectomy were 74.5% and 31.7%, respectively. Multivariate analyses revealed that tumor number before hepatectomy ≥3 (hazard ratio 3.59, P = .019), des-γ-carboxy prothrombin >200 mAU/mL (hazard ratio 3.36, P = .045), and red blood cell transfusion (hazard ratio 11.03, P = .0008) were independent prognostic factors for overall survival. Male sex (hazard ratio 3.74, P = .029), bilobar tumor distribution (hazard ratio 3.65, P = .004), and red blood cell transfusion (hazard ratio 6.22, P = .0026) were independent prognostic factors for disease-free survival. Disease progressions after portal vein embolization, including increases in tumor size, tumor number, α-fetoprotein, lens culinaris agglutinin-reactive fraction of α-fetoprotein, and des-γ-carboxy prothrombin, were observed in 22.8%, 14.0%, 29.8%, 19.3%, and 47.4% of patients, respectively. Only an increase of tumor number significantly decreased the disease-free survival rate after hepatectomy in a univariate analysis, and none of the variables affected overall survival.

CONCLUSION

Disease progression after portal vein embolization did not affect long-term survival in patients with hepatocellular carcinoma if the planned subsequent hepatectomy could be completed.

Selection and clinical significance of individualized treatment for metastatic liver cancer

The liver is one of the most common target organs for metastasis of malignant tumors, with a metastasis rate of 11.1%. Approximately 40% of patients with malignant tumors will develop liver metastasis. Metastatic liver cancer not only exhibits individualized difference in the origin of primary tumor, tumor gene, and biological behavior, but also varies in the stage of progression, anatomic characteristics, organ function, and complications. In view of the different sources and pathways of metastatic tumors, the treatment of metastatic liver cancer involves two aspects: primary tumor and liver metastasis. How to choose surgery, local ablation, chemotherapy, molecular targeted drugs, endocrine therapy, biological and immune therapy, and radiotherapy as well as the treatment opportunity rationally is the key to the treatment of metastatic liver cancer. Advanced imaging techniques are used to determine the size, number, location, and blood supply of metastatic liver cancer, so as to provide an objective basis for making an accurate individualized treatment plan for metastatic liver cancer. At present, any single therapy for metastatic liver cancer has its own indications. If a metastatic liver tumor cannot be resected radically , the use of a single therapy is difficult to cure or control the progression of the tumor. In this case, it is necessary to combine two or more than two kinds of treatment methods to achieve the synergistic effect. According to the specific condition of patients with metastatic liver cancer, the individual characteristics of the patients should be analyzed by experienced clinicians to formulate an individualized treatment plan in accordance with the principles of evidence-based medicine, so as to make the patients benefit most from the plan, improve the quality of life, and prolong the survival time.

Liver-specific deletion of LASS2 delayed regeneration of mouse liver after partial hepatectomy

The capacity of liver regeneration is critical for patients with liver diseases. However, cellular and molecular mechanisms of liver regeneration are still incompletely defined. Here, we assessed roles of LASS2 in liver regeneration following partial hepatectomy (PHx) in mice. Our results showed that protein level of LASS2 remarkably increased during liver regeneration after PHx in wildtype (WT) mice. Comparing to WT mice, liver regeneration index after PHx was significantly decreased from day 1 to day 5 in liver-specific LASS2 knockout (LASS2-LKO) mice. Interestingly, liver mass of LASS2-LKO mice could sufficiently recover at day 14 after PHx. Immunohistochemistry (IHC) and western blot analyses revealed that proliferation markers, such as PCNA and Ki67, were potently reduced during liver regeneration in LASS2-LKO mice. In addition, several cell cycle related molecules, such as cyclin A, CDK2 and p-Rb, were decreased in LASS2-LKO mice after PHx. Co-immunoprecipitation assay further revealed a decreased formation of CDK4/cyclin D1 complex after PHx in LASS2-LKO mice. However, phosphorylation of Akt was significantly activated from day 2 after PHx in LASS2-LKO mice when compared with that in WT mice, which may explain the recovery of liver mass at the late stage of liver regeneration in LASS2-LKO mice. Taken together, we conclude that LASS2 plays an important role in efficient liver regeneration in response to PHx.

[Portal vein embolization: Present and future]

Portal vein embolization consists of occluding a part of the portal venous system in order to achieve the hypertrophy of the non-embolized liver segments. This technique is used during the preoperative period of major liver resection when the future remnant liver (FRL) volume is insufficient, exposing to postoperative liver failure, main cause of death after major hepatectomy. Portal vein embolization indication depends on the FRL, commonly assessed by its volume. Nowadays, FRL function evaluation seems more relevant and can be measured by 99mTc labelled mebrofenin scintigraphy. Portal vein embolization procedure is mostly performed with percutaneous trans-hepatic access by using ultrasonography guidance and consists of embolic agent injection, such as cyanoacrylate, in the targeted portal vein branches with fluoroscopic guidance. It is a safe and well-tolerated technique, with extremely low morbi-mortality. Portal vein embolization leads to sufficient FRL hypertrophy in about 80% of patients, allowing them to undergo surgery from which they were initially rejected. The two main reasons of non-resection are tumor progression (≈15% of cases) and FRL insufficient hypertrophy (≈5% of cases). When portal vein embolization is not enough to obtain adequate FRL regeneration, hepatic vein embolization may potentiate its effect (liver venous deprivation technique).

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) does not affect proliferation, apoptosis, or angiogenesis as compared to standard liver resection for colorectal liver metastases

Background

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) is a novel two-stage strategy to induce rapid hypertrophy of the future liver remnant (FLR) when patients are in danger of postoperative liver failure due to insufficient FLR. However, the effects of ALPPS on colorectal liver metastases (CRLM) are not clear so far. The aim of our study was to determine whether ALPPS induces proliferation, apoptosis, or vascularization compared to standard (one-stage) liver resection.

Methods

Six patients who underwent ALPPS were matched with 12 patients undergoing standard liver resection regarding characteristics of the metastases (size, number), time of appearance (syn-/metachronous), preoperative chemotherapy, primary tumor (localization, TNM stage, grading), and patient variables (gender, age). The largest resected metastasis was used for the analyses. Tissue was stained for tumor cell proliferation (Ki67), apoptosis (TUNEL, caspase-3), vascularization (CD31), and pericytes (αSMA).

Results

Vascularization (CD31; p = 0.149), proliferation (Mib-1; p = 0.244), and αSMA expression (p = 0.205) did not significantly differ between the two groups, although a trend towards less proliferation and αSMA expression was observed in patients undergoing ALPPS. Concerning apoptosis, caspase-3 staining showed significantly fewer apoptotic cells upon ALPPS (p < 0.0001), but this was not confirmed by TUNEL staining (p = 0.7344).

Conclusions

ALPPS does not induce proliferation, apoptosis, or vascularization of CRLM when compared to standard liver resection.