Three hundred and one consecutive extended right hepatectomies: evaluation of outcome based on systematic liver volumetry

The roles of continuous and discontinuous proliferations on hepatitis B virus infection

The proliferation of both uninfected and infected hepatocytes, as well as the recycling effects of rcDNA-containing capsids are two key mechanisms playing significant roles in the persistence and clearance of hepatitis B virus (HBV) infection. In this study, the temporal dynamics of this viral infection is investigated through two intercellular mathematical models considering proliferation of both types of hepatocytes (uninfected and infected) and recycling effects of capsids. Both models are formulated on the basis of a key finding in the existing literature: mitosis of an infected hepatocytes yields in two uninfected progenies. In the first model (defined by P-model), we examine the continuous proliferation (which occur continuously), while the second one (defined by M-model) deals with the discontinuous proliferation (happen when the concentration of liver cells decreases to less than 70% of its initial concentration). The proposed models are calibrated with the experimental data obtained from an adult chimpanzee. Results of this study suggest that when both hepatocytes proliferate with equal rate, proliferation helps the individual in a rapid recovery from the acute infection whereas in case of chronic infection, the severity of the infection increases. On the other hand, if the infected hepatocytes proliferate at a different rate that of uninfected hepatocytes, the proliferation of uninfected hepatocytes contributes to increase the infection, but the proliferation of infected hepatocytes acts to reduce the infection from the long-term perspective. The global sensitivity analysis also shows the same results. Furthermore, it is also observed that the differences between the outcomes of continuous and discontinuous proliferations are significant and noteworthy.

Postoperative hepatic insufficiency despite preoperative portal vein embolization: Not just about the volumetrics

BACKGROUND

Future liver remnant hypertrophy is the primary endpoint of portal vein embolization before major hepatectomy. However, even when adequate future liver remnant is achieved, postoperative hepatic insufficiency is not universally averted. We aimed to identify preoperative risk factors of postoperative hepatic insufficiency despite the use of portal vein embolization.

METHODS

Patients who underwent portal vein embolization followed by major hepatectomy at 6 academic medical centers were retrospectively reviewed. Postoperative hepatic insufficiency was defined as postoperative peak bilirubin >7 mg/dL. Preoperative variables associated with postoperative hepatic insufficiency were analyzed.

RESULTS

From 2008 to 2019, 164 patients underwent portal vein embolization followed by major hepatectomy. Twenty (12%) patients developed postoperative hepatic insufficiency. On univariate analysis, postoperative hepatic insufficiency was associated with older age, performance status, preoperative biliary drainage, smaller pre- and post-portal vein embolization future liver remnant volumes, diagnosis of cholangiocarcinoma/gallbladder cancer, and preoperative cholangitis. There was significant future liver remnant hypertrophy noted even in the setting of postoperative hepatic insufficiency (from 27% to 39%); however, degree of hypertrophy >5% (100% vs 93%, P = .6) and kinetic growth rate >2%/week (95% vs 82%, P = .3) did not differ between the postoperative hepatic insufficiency and non-postoperative hepatic insufficiency groups. On multivariate analysis, the diagnosis of cholangiocarcinoma/gallbladder cancer and preoperative cholangitis (postoperative hepatic insufficiency incidence 34% and 62%, respectively), but not future liver remnant volumetrics, were independently associated with postoperative hepatic insufficiency. Postoperative hepatic insufficiency raised post-hepatectomy 90-day mortality from 3.5% to 45% and hospitalization from 7 days to 16 days (both P < .001).

CONCLUSION

Postoperative hepatic insufficiency still occurs in 12% of patients after major hepatectomy despite preoperative portal vein embolization. In addition to traditional volumetric information, surgeons should be aware of preoperative cholangitis and cholangiocarcinoma/gallbladder cancer as powerful predictors of this fatal complication.

Safety and efficacy of combined portal and hepatic vein embolisation in patients with colorectal liver metastases (DRAGON1): a multicentre, single-arm clinical trial

Background

Major liver resection is often required for complete clearance of colorectal liver metastases (CRLM). Patients with insufficient future liver remnant (FLR) volume/function are at high risk of post-hepatectomy liver failure (PHLF) and require FLR hypertrophy-inducing procedures to enable safe resection. The most recent variant of these procedures is combined portal and hepatic vein embolization (PVE/HVE). The DRAGON 1 trial evaluates the safety and efficacy of PVE/HVE, while assessing recruitment potential for the DRAGON 2 randomized trial.

Methods

DRAGON 1 is a prospective, single-arm, international, multicenter trial. Patients with upfront unresectable CRLM due to a small FLR were included. The primary outcome was the ability of centers to recruit three patients and perform PVE/HVE and liver resection without 90-day mortality. Secondary outcomes included recruitment capacity, PVE/HVE technical details, FLR volume changes, complications, and resection rates. The study is registered at ClinicalTrials.gov, identifier: NCT04272931.

Findings

In total, 102 patients were included from 43 centers. Twenty-four centers (24/43 = 56%) recruited three or more patients, and 20 centers (20/43 = 47%) achieved this without 90-day mortality. Of 96 patients undergoing PVE/HVE, no post-embolization mortality occurred, though major complications were reported in two patients. Resection was completed in 86 patients (86/96 = 90%), with seven patients (7/86 = 8%) dying within 90 days. PHLF grade B/C (International Study Group of Liver Surgery criteria) occurred in 19 patients (19/86 = 22%).

Interpretation

DRAGON 1 demonstrates that PVE/HVE is safe, with no embolization-related mortality, low morbidity, and high resection rates in upfront unresectable CRLM.

Funding

The Dutch Cancer Society, National Institute for Health and Care Research UK, Maastricht UMC+, Abbott Laboratories and Guerbet.

Interpretable machine learning model for predicting post-hepatectomy liver failure in hepatocellular carcinoma

Post-hepatectomy liver failure (PHLF) is a severe complication following liver surgery. We aimed to develop a novel, interpretable machine learning (ML) model to predict PHLF. We enrolled 312 hepatocellular carcinoma (HCC) patients who underwent hepatectomy, and 30% of the samples were utilized for internal validation. Variable selection was performed using the least absolute shrinkage and selection operator regression in conjunction with random forest and recursive feature elimination (RF-RFE) algorithms. Subsequently, 12 distinct ML algorithms were employed to identify the optimal prediction model. The area under the receiver operating characteristic curve, calibration curves, and decision curve analysis (DCA) were utilized to assess the model's predictive accuracy. Additionally, an independent prospective validation was conducted with 62 patients. The SHapley Additive exPlanations (SHAP) analysis further explained the extreme gradient boosting (XGBoost) model. The XGBoost model exhibited the highest accuracy with AUCs of 0.983 and 0.981 in the training and validation cohorts among 12 ML models. Calibration curves and DCA confirmed the model's accuracy and clinical applicability. Compared with traditional models, the XGBoost model had a higher AUC. The prospective cohort (AUC = 0.942) further confirmed the generalization ability of the XGBoost model. SHAP identified the top three critical variables: total bilirubin (TBIL), MELD score, and ICG-R15. Moreover, the SHAP summary plot was used to illustrate the positive or negative effects of the features as influenced by XGBoost. The XGBoost model provides a good preoperative prediction of PHLF in patients with resectable HCC.

Propensity Score-Matched Analysis of Liver Venous Deprivation and Portal Vein Embolization Before Planned Hepatectomy in Patients with Extensive Colorectal Liver Metastases and High-Risk Factors for Inadequate Regeneration

BACKGROUND

Liver venous deprivation (LVD) is known to induce better future liver remnant (FLR) hypertrophy than portal vein embolization (PVE). The role of LVD, compared with PVE, in inducing FLR hypertrophy and allowing safe hepatectomy for patients with extensive colorectal liver metastases (CLM) and high-risk factors for inadequate hypertrophy remains unclear.

METHODS

Patients undergoing LVD (n = 22) were matched to patients undergoing PVE (n = 279) in a 1:3 ratio based on propensity scores, prior to planned hepatectomy for CLM at a single center (1998-2023). The propensity scores accounted for high-risk factors for inadequate hypertrophy, namely pre-procedure standardized FLR (sFLR), body mass index, number of systemic therapy cycles, an extension of PVE to segment IV portal vein branches, prior resection, and chemotherapy-associated liver injury.

RESULTS

The matched cohort included 78 patients (LVD, n = 22; PVE, n = 56). Baseline characteristics were comparable. The number of tumors in the whole liver was similar but more LVD patients had five or more tumors in the left liver (32% vs. 11%; p = 0.024). Post-procedure sFLR was similar but LVD patients had a significantly higher degree of hypertrophy (16% vs. 11%; p = 0.017) and kinetic growth rate (3.9 vs. 2.4% per week; p = 0.006). More LVD patients underwent extended right hepatectomy (93% vs. 55%; p = 0.008). Only one patient had postoperative hepatic insufficiency after PVE, and no patients died within 90 days of hepatectomy.

CONCLUSION

In patients with extensive CLM and high-risk factors, LVD is associated with better FLR hypertrophy compared with PVE and allows for safely performing curative-intent extended major hepatectomy.

Surgical Management of Colorectal Cancer Liver Metastases

Approximately 50% of colorectal cancer patients develop liver metastases. Hepatic metastases represent the most common cause of colorectal cancer-related mortality. Metastasectomy, if possible, represents the most effective treatment strategy; 20% of patients will be cured and more than 50% survive at least 5 years. Nuances to treatment planning hinge on whether patients present with resectable disease upfront, whether the future liver remnant is adequate, and whether the primary tumor, if present, is colon versus rectal in origin. This article discusses considerations impacting our approach to patients with colorectal liver metastases and the role for various multimodal treatment options.

CEA Rebound After Discontinuation of Pre-Hepatectomy Chemotherapy Predicts Worse Outcomes After Resection of Colorectal Cancer Liver Metastases

BACKGROUND

Carcinoembryonic antigen (CEA) levels may vary with administration and discontinuation of pre-hepatectomy chemotherapy in patients undergoing resection of colorectal cancer liver metastases (CLM). The prognostic significance of these changes, termed CEA dynamics, is unclear.

PATIENTS AND METHODS

Consecutive patients undergoing hepatectomy for CLM (2001-2021) at a comprehensive cancer center were included. CEA dynamics were classified as CEA normal (CEA < 5 ng/mL before, during, and after chemotherapy), CEA decrease (elevated CEA levels that drop during and after chemotherapy), and CEA rebound (elevated CEA levels that drop during chemotherapy but rebound upon discontinuation). Recurrence-free (RFS), hepatic-specific disease-free (hDFS), and overall survival (OS) were compared across CEA dynamics groups.

RESULTS

Of 903 patients, 254 (28%) were CEA normal, 423 (47%) were CEA decrease, and 226 (25%) were CEA rebound. Median RFS was 15.9 months, median hDFS was not reached, and median OS was 11.9 years for CEA normal patients. By comparison, CEA decrease and CEA rebound patients had shorter median RFS (12.2 months, P = 0.002 and 7.4 months, P < 0.001, respectively), shorter median hDFS (29.1 months, P = 0.003 and 14.8 months, P < 0.001, respectively), and shorter median OS (7.1 years, P = 0.131, and 4.9 years, P < 0.001, respectively). On multivariable analysis, CEA rebound was an independent predictor of worse RFS [hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.16-1.93], hDFS (HR 1.39, 95% CI 1.03-1.88), and OS (HR 1.79, 95% CI 1.18-2.73). Among patients with CEA rebound, RAS-BRAF/TP53 comutation and multiple tumors predicted worse OS while APC mutation predicted improved OS.

CONCLUSION

CEA rebound between pre-hepatectomy chemotherapy discontinuation and CLM resection is associated with worse oncologic outcomes, particularly in patients with aggressive tumor biology, and may help frame patient and surgeon expectations ahead of CLM resection.

An anatomical analysis of liver volume and quality by ethnicity in a New Zealand population

BACKGROUND

Post-hepatectomy liver failure is a major cause of mortality, where future liver remnant (FLR) is the key controllable factor. Recommended minimum FLR is influenced by quality of liver parenchyma. Historical research has often failed to include Māori and Pacific Island (PI) populations despite worse health outcomes. Liver analysis by ethnicity is one such example of this. The aims were to determine digital FLR for various anatomical hepatectomies, investigate any correlations between computed tomography (CT) hepatic textural analysis and body mass index (BMI); and assess the variance of these relationships for different ethnicities.

METHOD

One hundred and fifty-one patients who underwent abdominal CT scans at Burwood Hospital, Christchurch were retrospectively analysed. Māori and PI patients were selectively recruited to represent New Zealand's diversity. Liver volumetry, segmental ratio, and intra-hepatic fat deposits (IHFD) per ethnicity were examined.

RESULTS

Median age of the cohort was 66 (19-95) and 75 (50%) were males. 68%, 23% and 9% patients identified as being European, Māori/PI and Asian, respectively. No statistically significant difference in volume or segment/total volume ratio were noted across different ethnicities. Obese patients had higher IHFD compared with overweight and normal BMI groups. When stratified across ethnic groups, higher IHFD were observed in Asian compared with Māori/PI populations, despite lower BMI.

CONCLUSION

No significant variances in liver volumetry were found across different ethnic groups in New Zealand. However association between BMI and IHFD varied across different ethnic cohorts. Consequently, knowledge of liver volumetry is not enough; patient liver quality and ethnicity should considered for hepatic-surgery planning.

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.

Laparoscopic versus open surgery for liver resection: a multicenter cohort study

The relative risk and benefits of Laparoscopic liver resection (LLR) are still controversial. This study aimed to evaluate perioperative and survival outcomes for three primary malignant liver tumors related outcomes following LLR. Data from three Homogeneous-High-Volume-Expert-Centers were collected. Multivariable logistic regression analysis was performed for the association between LLR, and major complications defined as Clavien-Dindo Classification grade ≥ II. Multivariable Cox proportional hazards regression was used to explore the impact of LLR on primary malignant liver tumor survival. Overall, 5886 patients underwent liver resection, of which 1991 underwent LLR. After adjusting for covariables, LLR had significantly lower rate of CDC grade ≥ II (OR = 0.56, 95% CI: 0.48-0.67, P < 0.001). Interaction analysis showed that LLR had significant association with sex, drinking status, history of abdominal surgery, and platelet count (all P < 0.05). The overall survival for each primary malignant liver tumor shown potential risk but without significantly different between LLR and OLR (all P > 0.05). LLR was associated with lower rate of major complications, especially in women, non-drinkers, those without a history of abdominal surgery, and those with normal platelet. For primary malignant liver tumors, the survival outcomes did not differ significantly between LLR and OLR.

Functional liver imaging score (FLIS) can predict adverse events in HCC patients

PURPOSE

To assess the performance of FLIS in predicting adverse outcomes, namely post-hepatectomy liver failure (PHLF) and death, in patients who underwent liver surgery for malignancies.

METHODS

All consecutive patients who underwent liver resection and 1.5 T gadoxetic acid MR were enrolled. PHLF and overall survival (OS) were collected. Two radiologists with 18 and 8 years of experience in abdominal imaging, blinded to clinical data, evaluated all images. Radiologists evaluated liver parenchymal enhancement (EnQS), biliary contrast excretion (ExQS), and signal intensity of the portal vein relative to the liver parenchyma (PVsQs). Reliability analysis was computed with Cohen's Kappa. Cox regression analysis was calculated to determine which factors are associated with PHLF and OS. Area Under the Receiver Operating Characteristic curve (AUROC) was computed.

RESULTS

150 patients were enrolled, 58 (38.7 %) in the HCC group and 92 (61.3 %) in the non-HCC group. The reliability analysis between the two readers was almost perfect (κ = 0.998). The multivariate Cox analysis showed that only post-surgical blood transfusions and major resection were associated with adverse events [HR=8.96 (7.98-9.88), p = 0.034, and HR=0.99 (0.781-1.121), p = 0.032, respectively] in the whole population. In the HCC group, the multivariable Cox analysis showed that blood transfusions, major resection and FLIS were associated with adverse outcomes [HR=13.133 (2.988-55.142), p = 0.009, HR=0.987 (0.244-1.987), p = 0.021, and HR=1.891 (1.772-3.471), p = 0.039]. The FLIS AUROC to predict adverse outcomes was 0.660 (95 %CIs = 0.484-0.836), with 87 % sensitivity and 33.3 % specificity (81.1-94.4 and 22.1-42.1).

CONCLUSIONS

FLIS can be considered a promising tool to preoperative depict patients at risk of PHLF and death.

Impact of the future liver remnant volume before major hepatectomy

INTRODUCTION

Following major liver resection, posthepatectomy liver failure (PHLF) is associated with a high mortality rate. As there is no therapy for PHLF available, avoidance remains the main goal. A sufficient future liver remnant (FLR) is one of the most important factors to reduce the risk for PHLF; however, it is not known which patients benefit of volumetric assessment prior to major surgery.

METHODS

A retrospective, bi-institutional cohort study was conducted including all patients who underwent major hepatectomy (extended right hepatectomy, right hepatectomy, extended left hepatectomy and left hepatectomy) between 2010 and 2023.

RESULTS

A total of 1511 major hepatectomies were included, with 29.4 % of patients undergoing FLR volume assessment preoperatively. Overall, PHLF B/C occurred in 9.8 % of cases. Multivariate analysis identified diabetes mellitus, extended right hepatectomy, perihilar cholangiocarcinoma (pCCA), gallbladder cancer (GBC) and cirrhosis as significant risk factors for PHLF B/C. High-risk patients (with one or more risk factors) had a 15 % overall incidence of PHLF, increasing to 32 % with a FLR <30 %, and 13 % with an FLR of 30-40 %. Low-risk patients with a FLR <30 % had a PHLF rate of 21 %, which decreased to 8 % and 5 % for FLRs of 30-40 % and >40 %, respectively. For right hepatectomy, the PHLF rate was 23 % in low-risk and 38 % in high-risk patients with FLR <30 %.

CONCLUSION

Patients scheduled for right hepatectomy and extended right hepatectomy should undergo volumetric assessment of the FLR. Volumetry should always be considered before major hepatectomy in patients with risk factors such as diabetes, cirrhosis, GBC and pCCA. In high-risk patients, a FLR cut-off of 30 % may be insufficient to prevent PHLF, and additional liver function assessment should be considered.

Preoperative Portal Vein Embolization: Basics Interventional Radiologists Need to Know

One of the major reasons for unresectability of the liver is that the remnant liver volume is insufficient to support postoperative liver function. Post-hepatectomy liver insufficiency is one of the most serious complications in patients undergoing major hepatic resection. Preoperative portal vein embolization is performed with the aim of inducing hypertrophy of the future liver remnant and is thought to reduce the risk of liver insufficiency after hepatectomy. We, interventional radiologists, are required to safely complete the procedure to promote future liver remnant hypertrophy as possible and understand portal vein anatomy variations and hemodynamics, embolization techniques, and how to deal with possible complications. The basic information interventional radiologists need to know about preoperative portal vein embolization is discussed in this review.

3-D reconstruction in liver surgery: a systematic review

BACKGROUND

Three-dimensional reconstruction of the liver offers several advantages to the surgeon before and during liver resection. This review discusses the factors behind the use of liver 3-D reconstruction.

METHODS

Systematic electronic search, according to PRISMA criteria, was performed. A literature search of scientific papers was performed until October 2023. Articles were chosen based on reference to 3-D liver reconstruction and their use in liver surgery. GRADE methodology and the modified Newcastle-Ottawa scale were used to assess the quality of the studies.

RESULTS

The research included 47 articles and 7724 patients were analyzed. Preoperative planning was performed with 3-D liver reconstruction in the 87.2% of the studies. Most of preoperative 3-D liver reconstructions were performed in the planning of complex or major hepatectomies. Complex hepatectomies were performed in 64.3% patients. The 55.3% of the studies reported an improved navigation and accuracy during liver resection. Four studies (8.6%) on living donor liver transplant (LDLT) concluded that 3-D liver reconstruction is useful for graft selection and vascular preservation. Nine papers (19.1%) reported an accurate measurement of future liver remnant.

CONCLUSION

Liver 3-D reconstruction helps surgeons in the planning of liver surgery, especially in liver graft and complex liver resections, increasing the accuracy of the surgical resection.

Conversion Therapy to Transplant or Surgical Resection in Patients with Unresectable Hepatocellular Carcinoma Treated with Boosted Dose of Yttrium-90 Radiation Segmentectomy

BACKGROUND/OBJECTIVES

The aim of this study was to assess the efficacy of boosted dose yttrium-90 radioembolization (TARE) as a modality for conversion therapy to transplant or surgical resection in patients with unresectable hepatocellular carcinoma (HCC).

METHODS

In this single-center retrospective study, all patients with a diagnosis of HCC who were treated with boosted dose TARE (>190 Gy) between January 2013 and December 2023 were reviewed. Treatment response and decrease in tumor size were assessed with the RECIST v1.1 and mRECIST criteria. Milan and University of California, San Francisco (UCSF), criteria were used to determine transplant eligibility, and Barcelona Clinic Liver Cancer (BCLC) surgical resection recommendations were used to evaluate tumor resectability.

RESULTS

Thirty-eight patients with primary HCC who were treated with boosted dose TARE were retrospectively analyzed. The majority of the patients were Child-Pugh A (n = 35; 92.1%), BCLC C (n = 17; 44.7%), and ECOG performance status 0 (n = 25; 65.8%). The mean sum of the target lesions was 6.0 cm (standard deviation; SD = 4.0). The objective response rate (ORR) was 31.6% by RECIST and 84.2% by mRECIST. The disease control rate (DCR) was 94.7% by both RECIST and mRECIST. Among patients outside of Milan or UCSF, 13/25 (52.0%, Milan) and 9/19 (47.4%, UCSF) patients were successfully converted to within transplant criteria. Of patients who were initially unresectable, conversion was successful in 7/26 (26.9%) patients.

CONCLUSIONS

This study provides further real-world data demonstrating that boosted-dose TARE is an effective modality for conversion of patients with unresectable HCC to transplant or resection.

Comparison of percutaneous microwave/radiofrequency ablation liver partition and portal vein embolization versus transarterial chemoembolization and portal vein embolization for planned hepatectomy with insufficient future liver remnant

BACKGROUND

In China, both percutaneous microwave/radiofrequency ablation liver partition plus portal vein embolization (PALPP) and transarterial chemoembolization (TACE) plus portal vein embolization (PVE) have been utilized in planned hepatectomy. However, there is a lack of comparative studies on the effectiveness of these two techniques for cases with insufficient future liver remnant (FLR).

METHODS

Patients were categorized into either the PALPP group or the TACE + PVE group. Clinical data, including FLR growth rate, complications, secondary resection rate, and overall survival rate, were compared and analyzed for both groups retrospectively.

RESULTS

Between December 2014 and October 2021, a total of 29 patients underwent TACE + PVE (n = 12) and PALPP (n = 17). In the TACE + PVE group, 7 patients successfully underwent two-stage hepatectomy, while in the PALPP group, 13 patients underwent the procedure (two-stage resection rate: 58.3% vs. 76.5%, P = 0.42). There were no significant differences in postoperative complications of one-stage procedures (11.8% vs. 8.3%, P > 0.05) and second-stage resection complication (0% vs. 46.2%, P = 0.05) between the TACE + PVE and PALPP groups. However, the PALPP group demonstrated a shorter time to FLR volume growth for second-stage resection (18.5 days vs. 66 days, P = 0.001) and KGR (58.5 ml/week vs. 7.7 ml/week, P = 0.001).

CONCLUSIONS

Compared with TACE + PVE, PALPP results in a more significant increase in FLR volume and a higher rate of two-stage resection without increasing postoperative complications.

Role of liver augmentation prior to hepatic resection - a survey on standards, procedures, and indications in Germany, Switzerland, and Austria

PURPOSE

For primary and secondary liver tumors oncological resection remains a chance of cure. Augmentation of functional liver tissue may be necessary to preserve sufficient future liver remnant (FLR). Clinical decision-making on liver augmentation techniques and indications may differ internationally. Thus, this study aims to identify standards of liver augmentation in hepato-pancreatico-biliary (HPB) centers in Germany, Switzerland, and Austria.

METHODS

Using a web-based survey, 48 hospitals in Germany, Switzerland, and Austria were invited to report their surgical indication, standard procedures, and results of liver augmentation.

RESULTS

Forty (83.3%) of the hospitals invited participated. Most of the hospitals were certified liver centers (55%), performing complex surgeries such as liver transplantation (57.5%) and ALPPS (80%). The standard liver augmentation technique in all countries was portal vein embolization (PVE; 56%), followed by ALPPS (32.1%) in Germany or PVE with hepatic vein embolization (33.3%) in Switzerland and Austria. Standard procedure for liver augmentation did not correlate with certification as liver center, performance of liver transplantation or ALPPS. Surgical indication for PVE varied depending on tumor entity. Most hospitals rated the importance of PVE before resection of cholangiocarcinoma or colorectal metastases as high, while PVE for hepatocellular carcinoma was rated as low.

CONCLUSION

The survey gives an overview of the clinical routine in HPB centers in Germany, Austria, and Switzerland. PVE seems to dominate as standard technique to increase the FLR. However, there is a variety in the main indication for liver augmentation. Further studies are necessary evaluating the differing PVE techniques for liver augmentation.

The Cross-Sectional Area Ratio of Right-to-Left Portal Vein Predicts the Effect of Preoperative Right Portal Vein Embolization

Background and Objectives: Preoperative right portal vein embolization (RPVE) is often attempted before right hepatectomy for liver tumors to increase the future remnant liver volume (FRLV). Although many factors affecting FRLV have been discussed, few studies have focused on the ratio of the cross-sectional area of the right portal vein to that of the left portal vein (RPVA/LPVA). The aim of the present study was to evaluate the effect of RPVA/LPVA on predicting FRLV increase after RPVE. Materials and Methods: The data of 65 patients who had undergone RPVE to increase FRLV between 2004 and 2021 were investigated retrospectively. Using computed tomography scans, we measured the total liver volume (TLV), FRLV, the proportion of FRLV relative to TLV (FRLV%), the increase in FRLV% (ΔFRLV%), and RPVA/LPVA twice, immediately before and 2-3 weeks after RPVE; we analyzed the correlations among those variables, and determined prognostic factors for sufficient ΔFRLV%. Results: Fifty-four patients underwent hepatectomy. Based on the cut-off value of RPVA/LPVA, the patients were divided into low (RPVA/LPVA ≤ 1.20, N = 30) and high groups (RPVA/LPVA > 1.20, N = 35). The ΔFRLV% was significantly greater in the high group than in the low group (9.52% and 15.34%, respectively, p < 0.001). In a multivariable analysis, RPVA/LPVA (HR = 20.368, p < 0.001) was the most significant prognostic factor for sufficient ΔFRLV%. Conclusions: RPVE was more effective in patients with higher RPVA/LPVA, which is an easily accessible predictive factor for sufficient ΔFRLV%.

Reproducibility and efficiency of liver volumetry using manual method and liver analysis software

BACKGROUND

For liver volumetry, manual tracing on computed tomography (CT) images is time-consuming and operator dependent. To overcome these disadvantages, several three-dimensional simulation software programs have been developed; however, their efficacy has not fully been evaluated.

METHODS

Three physicians performed liver volumetry on preoperative CT images on 30 patients who underwent formal right hepatectomy, using manual tracing volumetry and two simulation software programs, SYNAPSE and syngo.via. The future liver remnant (FLR) was calculated using each method of volumetry. The primary endpoint was reproducibility and secondary outcomes were calculation time and learning curve.

RESULTS

The mean FLR was significantly lower for manual volumetry than for SYNAPSE or syngo.via; there was no significant difference in mean FLR between the two software-based methods. Reproducibility was lower for the manual method than for the software-based methods. Mean calculation time was shortest for SYNAPSE. For the two physicians unfamiliar with the software, no obvious learning curve was observed for using SYNAPSE, whereas learning curves were observed for using syngo.via.

CONCLUSIONS

Liver volumetry was more reproducible and faster with three-dimensional simulation software, especially SYNAPSE software, than with the conventional manual tracing method. Software can help even inexperienced physicians learn quickly how to perform liver volumetry.

Liver Late Effects in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

A pediatric normal tissue effects in the clinic (PENTEC) comprehensive review of patients with childhood cancer who received radiation therapy (RT) to the liver was performed to develop models that may inform RT dose constraints for the liver and improve risk forecasting of toxicities.

METHODS AND MATERIALS

A systematic literature search was performed to identify published data on hepatic toxicities in children. Treatment and outcome data were extracted and used to generate normal tissue complication probability (NTCP) models. Complications from both whole and partial liver irradiation were considered. For whole liver irradiation, total body irradiation and non-total body irradiation treatments were considered, but it was assumed that the entire liver received the prescribed dose. For partial liver irradiation, only Wilms tumor flank field RT could be analyzed. However, a prescribed dose assumption could not be applied, and there was a paucity of analyzable liver dosimetry data. To associate the dose-volume exposures with the partial volume complication data from flank irradiation, liver dose-volume metrics were reconstructed for Wilms tumor flank RT using age-specific computational phantoms as a function of field laterality and superior extent of the field.

RESULTS

The literature search identified 2103 investigations pertaining to hepatic sinusoidal obstructive syndrome (SOS) and liver failure in pediatric patients. All abstracts were screened, and 241 articles were reviewed in full by the study team. A model was developed to calculate the risk of developing SOS after whole liver RT. RT dose (P = .006) and receipt of nonalkylating chemotherapy (P = .01) were significant. Age <20 years at time of RT was borderline significant (P = .058). The model predicted a 2% risk of SOS with zero RT dose, 6.1% following 10 Gy, and 14.5% following 20 Gy to the whole liver (modeled as the linear-quadratic equivalent dose in 2-Gy fractions [α/β = 3 Gy]). Patients with Wilms tumor treated with right flank RT had a higher observed rate of SOS than patients receiving left flank RT, but data were insufficient to generate an NTCP model for partial liver irradiation. From the phantom-based dose reconstructions, mean liver dose was estimated to be 2.16 ± 1.15 Gy and 6.54 ± 2.50 Gy for left and right flank RT, respectively, using T10-T11 as the superior field border and a prescription dose of 10.8 Gy (based on dose reconstruction). Data were sparse regarding rates of late liver injury after RT, which suggests low rates of severe toxicity after treatment for common pediatric malignancies.

CONCLUSIONS

This pediatric normal tissue effects in the clinic (PENTEC) review provides an NTCP model to estimate the risk of hepatic SOS as a function of RT dose following whole liver RT and quantifies the range of mean liver doses from typical Wilms tumor flank irradiation fields. Patients treated with right flank RT had higher rates of SOS than patients treated with left flank RT, but data were insufficient to develop a model for partial liver irradiation. Risk of SOS was estimated to be approximately ≤6% in pediatric patients receiving whole liver doses of <10 Gy.

Prediction of post-hepatectomy liver failure by preoperative gadoxetate disodium-enhanced magnetic resonance imaging

BACKGROUND

Approximately 15% of patients experience post-hepatectomy liver failure after major hepatectomy. Poor hepatocyte uptake of gadoxetate disodium, a magnetic resonance imaging contrast agent, may be a predictor of post-hepatectomy liver failure.

METHODS

A retrospective cohort study of patients undergoing major hepatectomy (≥3 segments) with a preoperative gadoxetate disodium-enhanced magnetic resonance imaging was conducted. The liver signal intensity (standardized to the spleen) and the functional liver remnant was calculated to determine if this can predict post-hepatectomy liver failure after major hepatectomy.

RESULTS

In 134 patients, low signal intensity of the remnant liver standardized by signal intensity of the spleen in post-contrast images was associated with post-hepatectomy liver failure in multiple logistic regression analysis (Odds Ratio 0.112; 95% CI 0.023-0.551). In a subgroup of 33 patients with lower quartile of functional liver remnant, area under the curve analysis demonstrated a diagnostic accuracy of functional liver remnant to predict post-hepatectomy liver failure of 0.857 with a cut-off value for functional liver remnant of 1.4985 with 80.0% sensitivity and 89.3% specificity.

CONCLUSION

Functional liver remnant determined by gadoxetate disodium-enhanced magnetic resonance imaging is a predictor of post-hepatectomy liver failure which may help identify patients for resection, reducing morbidity and mortality.

Clinician overconfidence in visual estimation of the posthepatectomy liver remnant volume: A proximal source of liver failure after major hepatic resection?

BACKGROUND

Post-hepatectomy liver failure is a source of morbidity and mortality after major hepatectomy and is related to the volume of the future liver remnant. The accuracy of a clinician's ability to visually estimate the future liver remnant without formal computed tomography liver volumetry is unknown.

METHODS

Twenty physicians in diagnostic radiology, interventional radiology, and hepatopancreatobiliary surgery reviewed 20 computed tomography scans of patients without underlying liver pathology who were not scheduled for liver resection. We evaluated clinician accuracy to estimate the future liver remnant for 3 hypothetical major hepatic resections: left hepatectomy, right hepatectomy, and right trisectionectomy. The percent-difference between the mean and actual computed tomography liver volumetry (mean percent difference) was tested along with specialty differences using mixed-effects regression analysis.

RESULTS

The actual future liver remnant (computed tomography liver volumetry) remaining after a hypothetical left hepatectomy ranged from 59% to 75% (physician estimated range: 50%-85%), 23% to 40% right hepatectomy (15%-50%), and 13% to 29% right trisectionectomy (8%-39%). For right hepatectomy, the mean future liver remnant was overestimated by 95% of clinicians with a mean percent difference of 22% (6%-45%; P < .001). For right trisectionectomy, 90% overestimated the future liver remnant by a mean percent difference of 25% (6%-50%; P < .001). Hepatopancreatobiliary surgeons overestimated the future liver remnant for proposed right hepatectomy and right trisectionectomy by a mean percent difference of 25% and 34%, respectively. Based on years of experience, providers with <10 years of experience had a greater mean percent difference than providers with 10+ years of experience for hypothetical major hepatic resections, but was only significantly higher for left hepatectomy (9% vs 6%, P = .002).

CONCLUSION

A clinician's ability to visually estimate the future liver remnant volume is inaccurate when compared to computed tomography liver volumetry. Clinicians tend to overestimate the future liver remnant volume, especially in patients with a small future liver remnant where the risk of posthepatectomy liver failure is greatest.

Novel multiparametric MRI detects improved future liver remnant quality post-dual vein embolization

BACKGROUND

Optimisation of the future liver remnant (FLR) is crucial to outcomes of extended liver resections. This study aimed to assess the quality of the FLR before and after dual vein embolization (DVE) by quantitative multiparametric MRI.

METHODS

Of 100 patients with liver metastases recruited in a clinical trial (Precision1:NCT04597710), ten consecutive patients with insufficient FLR underwent quantitative multiparametric MRI pre- and post-DVE (right portal and hepatic vein). FLR volume, liver fibro-inflammation (corrected T1) scores and fat percentage (proton density fat fraction, PDFF) were determined. Patient metrics were compared by Wilcoxon signed-rank test and statistical analysis done using R software.

RESULTS

All patients underwent uncomplicated DVE with improvement in liver remnant health, median 37 days after DVE: cT1 scores reduced from median (interquartile range) 790 ms (753-833 ms) to 741 ms (708-760 ms) p = 0.014 [healthy range <795 ms], as did PDFF from 11% (4-21%), to 3% (2-12%) p = 0.017 [healthy range <5.6%]. There was a significant increase in median (interquartile range) FLR volume from 33% (30-37%)% to 49% (44-52%), p = 0.002.

CONCLUSION

This non-invasive and reproducible MRI technique showed improvement in volume and quality of the FLR after DVE. This is a significant advance in our understanding of how to prevent liver failure in patients undergoing major liver surgery.

Sarcopenia does not affect liver regeneration and postoperative course after a major hepatectomy. A prospective study on 125 patients using CT volumetry and HIDA scintigraphy

BACKGROUND & OBJECTIVES

Sarcopenia is a morbi-mortality risk factor in digestive surgery, though its impact after major hepatectomy (MH) remains unknown. This prospective pilot study investigated whether volume and function of a regenerating liver is influenced by body composition.

METHODS

From 2011 to 2016, 125 consecutive patients had computed tomography and 99mTc-labelled-mebrofenin SPECT-scintigraphy before and after MH at day 7 and 1 month for measurements of liver volumes and functions. L3 vertebra muscle mass identified sarcopenia. Primary endpoint was the impact of sarcopenia on regeneration capacities (i.e. volume/function changes and post-hepatectomy liver failure (PHLF) rate). Secondary endpoint was 3-month morbi-mortality.

RESULTS

Sarcopenic patients (SP; N = 69) were significantly older than non-sarcopenic (NSP), with lower BMI and more malignancies, but with comparable liver function/volume at baseline. Postoperatively, SP showed higher rates of ISGLS_PHLF (24.6 % vs 10.9 %; p = 0.05) but with comparable rates of severe morbidity (23.2 % vs 16.4 %; p = 0.35), overall (8.7 % vs 3.6 %; p = 0.3) and PHLF-related mortality (8,7 % vs 1.8 %; p = 0.075). After matching on the extent of resection or using propensity score, regeneration and PHLF rates were similar.

CONCLUSION

This prospective study using first sequential SPECT-scintigraphy showed that sarcopenia by itself does not affect liver regeneration capacities and short-term postoperative course after MH.

Liver volumetry and liver-regenerative interventions: history, rationale, and emerging tools

BACKGROUND

Postoperative hepatic insufficiency (PHI) is the most feared complication after hepatectomy. Volume of the future liver remnant (FLR) is one objectively measurable indicator to identify patients at risk of PHI. In this review, we summarized the development and rationale for the use of liver volumetry and liver-regenerative interventions and highlighted emerging tools that could yield new advancements in liver volumetry.

METHODS

A review of MEDLINE/PubMed, Embase, and Cochrane Library databases was conducted to identify literature related to liver volumetry. The references of relevant articles were reviewed to identify additional publications.

RESULTS

Liver volumetry based on radiologic imaging was developed in the 1980s to identify patients at risk of PHI and later used in the 1990s to evaluate grafts for living donor living transplantation. The field evolved in the 2000s by the introduction of standardized FLR based on the hepatic metabolic demands and in the 2010s by the introduction of the degree of hypertrophy and kinetic growth rate as measures of the FLR regenerative and functional capacity. Several liver-regenerative interventions, most notably portal vein embolization, are used to increase resectability and reduce the risk of PHI. In parallel with the increase in automation and machine assistance to physicians, many semi- and fully automated tools are being developed to facilitate liver volumetry.

CONCLUSION

Liver volumetry is the most reliable tool to detect patients at risk of PHI. Advances in imaging analysis technologies, newly developed functional measures, and liver-regenerative interventions have been improving our ability to perform safe hepatectomy.

Local Therapy Improves Survival for Early Recurrence After Resection of Colorectal Liver Metastases

BACKGROUND

Early recurrence following hepatectomy for colorectal liver metastases (CLM) is associated with worse survival; yet, impact of further local therapy is unclear. We sought to evaluate whether local therapy benefits patients with early recurrence following hepatectomy for CLM.

METHODS

Clinicopathologic and survival outcomes of patients managed with hepatectomy for CLM (1/2001-12/2020) were queried from a prospectively maintained database. Timing of recurrence was stratified as early (recurrence-free survival [RFS] < 6 months), intermediate (RFS 6-12 months), and later (RFS > 12 months). Local therapy was defined as ablation, resection, or radiation.

RESULTS

Of 671 patients, 541 (81%) recurred with 189 (28%) early, 180 (27%) intermediate, and 172 (26%) later recurrences. Local therapy for recurrence resulted in improved survival, regardless of recurrence timing (early 78 vs. 32 months, intermediate 72 vs. 39 months, later 132 vs. 65 months, all p < 0.001). Following recurrence, treatment with local therapy (hazard ratio [HR] = 0.24), liver and extrahepatic recurrence (HR = 1.81), RAS + TP53 co-mutation (HR = 1.52), and SMAD4 mutation (HR = 1.92) were independently associated with overall survival (all p ≤ 0.002). Among patients with recurrence treated by local therapy, patients older than 65 years (HR 1.79), liver and extrahepatic recurrence (HR 2.05), primary site or other recurrence (HR 1.90), RAS-TP53 co-mutation (HR 1.63), and SMAD4 mutation (HR 2.06) had shorter post-local therapy survival (all p ≤ 0.04).

CONCLUSIONS

While most patients recur after hepatectomy for CLM, local therapy may result in long-term survival despite early recurrence. Somatic mutational profiling may help to guide the multidisciplinary consideration of local therapy after recurrence.

Opportunistic Extraction of Quantitative CT Biomarkers: Turning the Incidental Into Prognostic Information

The past two decades have seen a significant increase in the use of CT, with a corresponding rise in the mean population radiation dose. This rise in CT use has caused improved diagnostic certainty in conditions that were not previously routinely evaluated using CT, such as headaches, back pain, and chest pain. Unused data, unrelated to the primary diagnosis, embedded within these scans have the potential to provide organ-specific measurements that can be used to prognosticate or risk-profile patients for a wide variety of conditions. The recent increased availability of computing power, expertise and software for automated segmentation and measurements, assisted by artificial intelligence, provides a conducive environment for the deployment of these analyses into routine use. Data gathering from CT has the potential to add value to examinations and help offset the public perception of harm from radiation exposure. We review the potential for the collection of these data and propose the incorporation of this strategy into routine clinical practice.

Bifidobacterium longum promotes postoperative liver function recovery in patients with hepatocellular carcinoma

Timely liver function recovery (LFR) is crucial for postoperative hepatocellular carcinoma (HCC) patients. Here, we established the significance of LFR on patient long-term survival through retrospective and prospective cohorts and identified a key gut microbe, Bifidobacterium longum, depleted in patients with delayed recovery. Fecal microbiota transfer from HCC patients with delayed recovery to mice similarly impacted recovery time post hepatectomy. However, oral gavage of B. longum improved liver function and repair in these mice. In a clinical trial of HCC patients, orally administering a probiotic bacteria cocktail containing B. longum reduced the rates of delayed recovery, shortened hospital stays, and improved overall 1-year survival. These benefits, attributed to diminished liver inflammation, reduced liver fibrosis, and hepatocyte proliferation, were associated with changes in key metabolic pathways, including 5-hydroxytryptamine, secondary bile acids, and short-chain fatty acids. Our findings propose that gut microbiota modulation can enhance LFR, thereby improving postoperative outcomes for HCC patients.

Imaging of the hepatic arterial infusion pump: Primer for radiologists

Hepatic arterial infusion (HAI) pumps are used to deliver liver-directed therapy by allowing the administration of selective chemotherapy to the liver via a catheter implanted most commonly into the gastroduodenal artery connected to a subcutaneous pump. This selective administration helps maximize the chemotherapeutic effect within the hepatic tumors while minimizing systemic toxicity. While HAI therapy has primarily been used to treat liver-only metastatic colorectal cancer, the indications have expanded to other malignancies, including intrahepatic cholangiocarcinoma. Radiologists play an important role in pre-operative planning, assessment of treatment response, and evaluation for potential complications using various imaging studies, including computed tomography angiography, magnetic resonance imaging, and perfusion scintigraphy. This article describes the radiologist's role as part of a multi-disciplinary oncology team to help maximize the success of HAI therapy and also helps radiologists familiarize themselves with various aspects of HAI pumps.

Predictive Model of Oxaliplatin-induced Liver Injury Based on Artificial Neural Network and Logistic Regression

BACKGROUND AND AIMS

Identifying potential high-risk groups of oxaliplatin-induced liver injury (OILI) is valuable, but tools are lacking. So artificial neural network (ANN) and logistic regression (LR) models will be developed to predict the risk of OILI.

METHODS

The medical information of patients treated with oxaliplatin between May and November 2016 at 10 hospitals was collected prospectively. We used the updated Roussel Uclaf causality assessment method (RUCAM) to identify cases of OILI and summarized the patient and medication characteristics. Furthermore, the ANN and LR models for predicting the risk of OILI were developed and evaluated.

RESULTS

The incidence of OILI was 3.65%. The median RUCAM score with interquartile range was 6 (4, 9). The ANN model performed similarly to the LR model in sensitivity, specificity, and accuracy. In discrimination, the area under the curve of the ANN model was larger (0.920>0.833, p=0.019). In calibration, the ANN model was slightly improved. The important predictors of both models overlapped partially, including age, chemotherapy regimens and cycles, single and total dose of OXA, glucocorticoid drugs, and antihistamine drugs.

CONCLUSIONS

When the discriminative and calibration ability was given priority, the ANN model outperformed the LR model in predicting the risk of OILI. Other chemotherapy drugs in oxaliplatin-based chemotherapy regimens could have different degrees of impact on OILI. We suspected that OILI may be idiosyncratic, and chemotherapy dose factors may be weakly correlated. Decision making on prophylactic medications needs to be carefully considered, and the actual preventive effect needed to be supported by more evidence.

British Society of Gastroenterology guidelines for the diagnosis and management of cholangiocarcinoma

These guidelines for the diagnosis and management of cholangiocarcinoma (CCA) were commissioned by the British Society of Gastroenterology liver section. The guideline writing committee included a multidisciplinary team of experts from various specialties involved in the management of CCA, as well as patient/public representatives from AMMF (the Cholangiocarcinoma Charity) and PSC Support. Quality of evidence is presented using the Appraisal of Guidelines for Research and Evaluation (AGREE II) format. The recommendations arising are to be used as guidance rather than as a strict protocol-based reference, as the management of patients with CCA is often complex and always requires individual patient-centred considerations.

Surgical outcomes of hepatocellular carcinoma with extrahepatic bile duct tumor thrombus: a multicenter study

Background

The long-term prognosis after surgery of patients with hepatocellular carcinoma (HCC) and extrahepatic bile duct tumor thrombus (Ex-BDTT) remains unknown. We aimed to identify the surgical outcomes of patients with HCC and Ex-BDTT.

Methods

A total of 138 patients with Ex-BDTT who underwent hepatectomy with preservation of the extrahepatic bile duct from five large hospitals in China between January 2009 and December 2017 were included. The Cox proportional hazards model was used to analyze overall survival (OS) and recurrence-free survival (RFS).

Results

With a median follow-up of 60 months (range, 1-127.8 months), the median OS and RFS of the patients were 28.6 and 8.9 months, respectively. The 1-, 3-, and 5-year OS rates of HCC patients with Ex-BDTT were 71.7%, 41.2%, and 33.5%, respectively, and the corresponding RFS rates were 43.5%, 21.7%, and 20.0%, respectively. Multivariate analysis identified that major hepatectomy, R0 resection, and major vascular invasion were independent prognostic factors for OS and RFS. In addition, preoperative serum total bilirubin ≥ 4.2 mg/dL was an independent prognostic factor for RFS.

Conclusion

Major hepatectomy with preservation of the extrahepatic bile duct can provide favorable long-term survival for HCC patients with Ex-BDTT.

Liver Anatomy 2.0 Quiz: Test Your Knowledge

The liver is one the largest organs in the abdomen and the most frequent site of metastases for gastrointestinal tumors. Surgery on this complex and highly vascularized organ can be associated with high morbidity even in experienced hands. A thorough understanding of liver anatomy is key to approaching liver surgery with confidence and preventing complications. The aim of this quiz is to provide an active learning tool for a comprehensive understanding of liver anatomy and its integration into clinical practice.

Recent advances in computerized imaging and its vital roles in liver disease diagnosis, preoperative planning, and interventional liver surgery: A review

The earliest and most accurate detection of the pathological manifestations of hepatic diseases ensures effective treatments and thus positive prognostic outcomes. In clinical settings, screening and determining the extent of a pathology are prominent factors in preparing remedial agents and administering appropriate therapeutic procedures. Moreover, in a patient undergoing liver resection, a realistic preoperative simulation of the subject-specific anatomy and physiology also plays a vital part in conducting initial assessments, making surgical decisions during the procedure, and anticipating postoperative results. Conventionally, various medical imaging modalities, e.g., computed tomography, magnetic resonance imaging, and positron emission tomography, have been employed to assist in these tasks. In fact, several standardized procedures, such as lesion detection and liver segmentation, are also incorporated into prominent commercial software packages. Thus far, most integrated software as a medical device typically involves tedious interactions from the physician, such as manual delineation and empirical adjustments, as per a given patient. With the rapid progress in digital health approaches, especially medical image analysis, a wide range of computer algorithms have been proposed to facilitate those procedures. They include pattern recognition of a liver, its periphery, and lesion, as well as pre- and postoperative simulations. Prior to clinical adoption, however, software must conform to regulatory requirements set by the governing agency, for instance, valid clinical association and analytical and clinical validation. Therefore, this paper provides a detailed account and discussion of the state-of-the-art methods for liver image analyses, visualization, and simulation in the literature. Emphasis is placed upon their concepts, algorithmic classifications, merits, limitations, clinical considerations, and future research trends.

Postoperative Liver Failure: Definitions, Risk factors, Prediction Models and Prevention Strategies

BACKGROUND

Liver resection is the treatment for a variety of benign and malignant conditions. Despite advances in preoperative selection, surgical technique, and perioperative management, post hepatectomy liver failure (PHLF) is still a leading cause of morbidity and mortality following liver resection.

METHODS

A review of the literature was performed utilizing MEDLINE/PubMed and Web of Science databases in May of 2023. The MESH terms "liver failure," "liver insufficiency," and "hepatic failure" in combination with "liver surgery," "liver resection," and "hepatectomy" were searched in the title and/or abstract. The references of relevant articles were reviewed to identify additional eligible publications.

RESULTS

PHLF can have devastating physiological consequences. In general, risk factors can be categorized as patient-related, primary liver function-related, or perioperative factors. Currently, no effective treatment options are available and the management of PHLF is largely supportive. Therefore, identifying risk factors and preventative strategies for PHLF is paramount. Ensuring an adequate future liver remnant is important to mitigate risk of PHLF. Dynamic liver function tests provide more objective assessment of liver function based on the metabolic capacity of the liver and have the advantage of easy administration, low cost, and easy reproducibility.

CONCLUSION

Given the absence of randomized data specifically related to the management of PHLF, current strategies are based on the principles of management of acute liver failure from any cause. In addition, goal-directed therapy for organ dysfunction, as well as identification and treatment of reversible factors in the postoperative period are critical.

Preoperative percutaneous or transvascular marking for curative resection of small liver tumours with potential for missing during hepatectomy: a study protocol for an open-label, single-arm phase II study

INTRODUCTION

Small liver tumours are difficult to identify during hepatectomy, which prevents curative tumour excision. Preoperative marking is a standard practice for small, deep-seated tumours in other solid organs; however, its effectiveness for liver tumours has not been validated. The objective of this study is to evaluate the effectiveness of preoperative markings for curative resection of small liver tumours.

METHODS AND ANALYSIS

This is an open-label, single-arm, single-centre, phase II study. Patients with liver tumours of ≤15 mm requiring hepatectomy will be enrolled and will undergo preoperative marking by placing a microcoil near the tumour using either the percutaneous or transvascular approach. The tumours, including the indwelling markers, will be excised. The primary endpoint will be the successful resection rate of liver tumours, defined as achieving a surgical margin of ≥5 mm and ≤15 mm. Secondary endpoints will include the results of preoperative marking and hepatectomy.

ETHICS AND DISSEMINATION

Ethical approval for this trial was obtained from the Ethical Committee for Clinical Research of Hiroshima University, Japan. The results will be published at an academic conference or by submitting a paper to a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

jRCTs062220088.

The Role of the Multiparametric MRI LiverMultiScanTM in the Quantitative Assessment of the Liver and Its Predicted Clinical Applications in Patients Undergoing Major Hepatic Resection for Colorectal Liver Metastasis

Liver biopsy remains the gold standard for the histological assessment of the liver. With clear disadvantages and the rise in the incidences of liver disease, the role of neoadjuvant chemotherapy in colorectal liver metastasis (CRLM) and an explosion of surgical management options available, non-invasive serological and imaging markers of liver histopathology have never been more pertinent in order to assess liver health and stratify patients considered for surgical intervention. Liver MRI is a leading modality in the assessment of hepatic malignancy. Recent technological advancements in multiparametric MRI software such as the LiverMultiScanTM offers an attractive non-invasive assay of anatomy and histopathology in the pre-operative setting, especially in the context of CRLM. This narrative review examines the evidence for the LiverMultiScanTM in the assessment of hepatic fibrosis, steatosis/steatohepatitis, and potential applications for chemotherapy-associated hepatic changes. We postulate its future role and the hurdles it must surpass in order to be implemented in the pre-operative management of patients undergoing hepatic resection for colorectal liver metastasis. Such a role likely extends to other hepatic malignancies planned for resection.

CT-derived extracellular volume and liver volumetry can predict posthepatectomy liver failure in hepatocellular carcinoma

OBJECTIVES

Posthepatectomy liver failure (PHLF) is a severe complication of liver resection. We aimed to develop and validate a model based on extracellular volume (ECV) and liver volumetry derived from computed tomography (CT) for preoperative predicting PHLF in resectable hepatocellular carcinoma (HCC) patients.

METHODS

A total of 393 resectable HCC patients from two hospitals were enrolled and underwent multiphasic contrast-enhanced CT before surgery. A total of 281 patients from our hospital were randomly divided into a training cohort (n = 181) and an internal validation cohort (n = 100), and 112 patients from another hospital formed the external validation cohort. CT-derived ECV was measured on nonenhanced and equilibrium phase images, and liver volumetry was measured on portal phase images. The model is composed of independent predictors of PHLF. The under the receiver operator characteristic curve (AUC) and calibration curve were used to reflect the predictive performance and calibration of the model. Comparison of AUCs used the DeLong test.

RESULTS

CT-derived ECV, measured future liver remnant (mFLR) ratio, and serum albumin were independent predictors for PHLF in resectable HCC patients. The AUC of the model was significantly higher than that of the ALBI score in the training cohort, internal validation cohort, and external validation cohort (all p < 0.001). The calibration curve of the model showed good consistency in the training cohort and the internal and external validation cohorts.

CONCLUSIONS

The novel model contributes to the preoperative prediction of PHLF in resectable HCC patients.

CRITICAL RELEVANCE STATEMENT

The novel model combined CT-derived extracellular volume, measured future liver remnant ratio, and serum albumin outperforms the albumin-bilirubin score for predicting posthepatectomy liver failure in patients with resectable hepatocellular carcinoma.

KEY POINTS

• CT-derived ECV correlated well with the fibrosis stage of the background liver. • CT-derived ECV and mFLR ratio were independent predictors for PHLF in HCC. • The AUC of the model was higher than the CT-derived ECV and mFLR ratio. • The model showed a superior predictive performance than that of the ALBI score.

E-AHPBA-ESSO-ESSR Innsbruck consensus guidelines for preoperative liver function assessment before hepatectomy

BACKGROUND

Posthepatectomy liver failure (PHLF) contributes significantly to morbidity and mortality after liver surgery. Standardized assessment of preoperative liver function is crucial to identify patients at risk. These European consensus guidelines provide guidance for preoperative patient assessment.

METHODS

A modified Delphi approach was used to achieve consensus. The expert panel consisted of hepatobiliary surgeons, radiologists, nuclear medicine specialists, and hepatologists. The guideline process was supervised by a methodologist and reviewed by a patient representative. A systematic literature search was performed in PubMed/MEDLINE, the Cochrane library, and the WHO International Clinical Trials Registry. Evidence assessment and statement development followed Scottish Intercollegiate Guidelines Network methodology.

RESULTS

Based on 271 publications covering 4 key areas, 21 statements (at least 85 per cent agreement) were produced (median level of evidence 2- to 2+). Only a few systematic reviews (2++) and one RCT (1+) were identified. Preoperative liver function assessment should be considered before complex resections, and in patients with suspected or known underlying liver disease, or chemotherapy-associated or drug-induced liver injury. Clinical assessment and blood-based scores reflecting liver function or portal hypertension (for example albumin/bilirubin, platelet count) aid in identifying risk of PHLF. Volumetry of the future liver remnant represents the foundation for assessment, and can be combined with indocyanine green clearance or LiMAx® according to local expertise and availability. Functional MRI and liver scintigraphy are alternatives, combining FLR volume and function in one examination.

CONCLUSION

These guidelines reflect established methods to assess preoperative liver function and PHLF risk, and have uncovered evidence gaps of interest for future research.

Magnetic resonance imaging and ultrasound elastography in the context of preclinical pharmacological research: significance for the 3R principles

The 3Rs principles-reduction, refinement, replacement-are at the core of preclinical research within drug discovery, which still relies to a great extent on the availability of models of disease in animals. Minimizing their distress, reducing their number as well as searching for means to replace them in experimental studies are constant objectives in this area. Due to its non-invasive character in vivo imaging supports these efforts by enabling repeated longitudinal assessments in each animal which serves as its own control, thereby enabling to reduce considerably the animal utilization in the experiments. The repetitive monitoring of pathology progression and the effects of therapy becomes feasible by assessment of quantitative biomarkers. Moreover, imaging has translational prospects by facilitating the comparison of studies performed in small rodents and humans. Also, learnings from the clinic may be potentially back-translated to preclinical settings and therefore contribute to refining animal investigations. By concentrating on activities around the application of magnetic resonance imaging (MRI) and ultrasound elastography to small rodent models of disease, we aim to illustrate how in vivo imaging contributes primarily to reduction and refinement in the context of pharmacological research.

A bibliometric and visualized analysis of preoperative future liver remnant augmentation techniques from 1997 to 2022

Background

The size and function of the future liver remnant (FLR) is an essential consideration for both eligibility for treatment and postoperative prognosis when planning surgical hepatectomy. Over time, a variety of preoperative FLR augmentation techniques have been investigated, from the earliest portal vein embolization (PVE) to the more recent Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and liver venous deprivation (LVD) procedures. Despite numerous publications on this topic, no bibliometric analysis has yet been conducted.

Methods

Web of Science Core Collection (WoSCC) database was searched to identify studies related to preoperative FLR augmentation techniques published from 1997 to 2022. The analysis was performed using the CiteSpace [version 6.1.R6 (64-bit)] and VOSviewer [version 1.6.19].

Results

A total of 973 academic studies were published by 4431 authors from 920 institutions in 51 countries/regions. The University of Zurich was the most published institution while Japan was the most productive country. Eduardo de Santibanes had the most published articles, and Masato Nagino was the most frequently co-cited author. The most frequently published journal was HPB, and the most cited journal was Ann Surg, with 8088 citations. The main aspects of preoperative FLR augmentation technique is to enhance surgical technology, expand clinical indications, prevent and treat postoperative complications, ensure long-term survival, and evaluate the growth rate of FLR. Recently, hot keywords in this field include ALPPS, LVD, and Hepatobiliary Scintigraphy.

Conclusion

This bibliometric analysis provides a comprehensive overview of preoperative FLR augmentation techniques, offering valuable insights and ideas for scholars in this field.

Preoperative Value of Contrast-Enhanced Ultrasound in Totally Laparoscopic Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy for Liver Tumors: A Preliminary Study

ABSTRACT

The clinical data of 15 cases that planned to receive totally laparoscopic associating liver partition and portal vein ligation for staged hepatectomy were retrospectively collected. Before the stage 1 operation, the size and number of the tumors in future liver remnant (FLR) and the presence of cancer embolus in the portal vein were assessed using contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT). Before the stage 2 operation, CEUS was performed to assess the presence of traffic blood flow between the diseased liver and FLR after round-the-liver ligation. Before the stage 1 operation, 5 cases with tumors in FLR were found by CEUS and 6 cases were found by CECT ( P > 0.05). Similarly, CEUS found 5 cases with cancer thrombus in portal vein, and CECT found 7 cases ( P = 0.500). The consistency between the 2 modalities was good (κ = 0.857, P < 0.05, κ = 0.727, P < 0.05, respectively). Before the stage 2 operation, CEUS confirmed that there were 7 cases without traffic blood flow between the diseased liver and FLR, and 3 cases with residual traffic blood flow. The daily growth rate of FLR in the group without traffic blood flow (mean rank = 7.00) was higher than that in the group with traffic blood flow (2.00) significantly ( P < 0.05). Contrast-enhanced ultrasound is a promising application in the preoperative evaluation of totally laparoscopic associating liver partition and portal vein ligation for staged hepatectomy.

Significance of predicted future liver remnant volume on liver failure risk after major hepatectomy: a case matched comparative study

INTRODUCTION

Future liver remnant volume (FLRV), a risk factor for liver failure (PHLF) after major hepatectomy (MH), is not routinely measured. This study aimed to evaluate the association between FLRV and PHLF.

PATIENTS AND METHODS

All patients undergoing MH (4 + segments) between 2011 and 2018 were identified from a prospectively maintained single-centre database. Perioperative data were collected for patients with PHLF, who were matched (1:2) with non-PHLF controls. FLRV and FLRV% (i.e., % of total liver volume) were calculated retrospectively from preoperative CT scans using Synapse-3D software, and compared between the PHLF and matched control groups.

RESULTS

Of 711 patients undergoing MH, PHLF occurred in 27 (3.8%), of whom 24 had preoperative CT scans available. These patients were matched to 48 non-PHLF controls, 98% of whom were classified as being at high risk of PHLF on preoperative risk scoring. FLRV% was significantly lower in the PHLF group, compared to matched controls (median: 28.7 vs. 35.2%, p = 0.010), with FLRV% < 30% in 58% and 29% of patients, respectively. Assessment of the ability of FLRV% to differentiate between PHLF and matched controls returned an area under the ROC curve of 0.69, and an optimal cut-off value of FLRV% < 31.5%, which yielded 79% sensitivity and 67% specificity.

CONCLUSIONS

FLRV% is significantly predictive of PHLF after MH, with over half of patients with PHLF having FLRV% < 30%. In light of this, we propose that all patients should undergo risk stratification prior to MH, with the high risk patients additionally being assessed with CT volumetry.

Main causes of death in advanced biliary tract cancer

BACKGROUND

There are no previous reports on the main causes of death in biliary tract cancer (BTC) patients. This study aimed to evaluate the main causes of death and survival rates in patients with BTC.

METHODS

We retrospectively evaluated 143 patients who were diagnosed with unresectable BTC between August 2010 and March 2020. We classified the main causes of death based on laboratory data, imaging studies, and medical records. The main causes of death evaluated included liver failure, cholangitis, cachexia, other causes associated with tumor progression, and complications. We also analyzed survival rates for each main cause of death.

RESULTS

After excluding patients who were lost to follow-up, living patients, and patients who had no records of laboratory data within 30 days before the date of death, 108 patients were analyzed. The main cause of death was cholangitis in 33 (30.6%), cachexia in 22 (20.4%), liver failure in 10 (9.3%), other causes associated with tumor progression in 18 (16.7%), and complications in 25 (23.2%) patients. Median overall survival (OS) was 334.0 days in the chemotherapy group and 75.0 days in the best supportive care (BSC) group. Survival analyzed according to the main cause of death was significantly different between the chemotherapy and BSC groups; OS for cachexia, cholangitis, liver failure, other causes associated with tumor progression, and complications, respectively, were 453.0, 499.0, 567.0, 205.0, and 327.5 days (p = 0.003) in the chemotherapy group and 219.0, 69.0, 34.0, 93.0, and 56.0 days (p = 0.001) in the BSC group.

CONCLUSION

The main causes of death in patients with advanced BTC are cholangitis, cachexia, liver failure, other causes associated with tumor progression, and complications. Other causes associated with tumor progression in the chemotherapy group, and liver failure in the BSC group as the main causes of death shortened the survival of BTC patients.

Interleukin-33 facilitates liver regeneration through serotonin-involved gut-liver axis

BACKGROUND AND AIMS

Insufficient liver regeneration causes post-hepatectomy liver failure and small-for-size syndrome. Identifying therapeutic targets to enhance hepatic regenerative capacity remains urgent. Recently, increased IL-33 was observed in patients undergoing liver resection and in mice after partial hepatectomy (PHx). The present study aims to investigate the role of IL-33 in liver regeneration after PHx and to elucidate its underlying mechanisms.

APPROACH AND RESULTS

We performed PHx in IL-33 -/- , suppression of tumorigenicity 2 (ST2) -/- , and wild-type control mice, and found deficiency of IL-33 or its receptor ST2 delayed liver regeneration. The insufficient liver regeneration could be normalized in IL-33 -/- but not ST2 -/- mice by recombinant murine IL-33 administration. Furthermore, we observed an increased level of serotonin in portal blood from wild-type mice, but not IL-33 -/- or ST2 -/- mice, after PHx. ST2 deficiency specifically in enterochromaffin cells recapitulated the phenotype of delayed liver regeneration observed in ST2 -/- mice. Moreover, the impeded liver regeneration in IL-33 -/- and ST2 -/- mice was restored to normal levels by the treatment with (±)-2,5-dimethoxy-4-iodoamphetamine, which is an agonist of the 5-hydroxytrytamine receptor (HTR)2A. Notably, in vitro experiments demonstrated that serotonin/HTR2A-induced hepatocyte proliferation is dependent on p70S6K activation.

CONCLUSIONS

Our study identified that IL-33 is pro-regenerative in a noninjurious model of liver resection. The underlying mechanism involved IL-33/ST2-induced increase of serotonin release from enterochromaffin cells to portal blood and subsequent HTR2A/p70S6K activation in hepatocytes by serotonin. The findings implicate the potential of targeting the IL-33/ST2/serotonin pathway to reduce the risk of post-hepatectomy liver failure and small-for-size syndrome.

Efficacy of a novel polyoxazoline-based hemostatic patch in liver and spleen surgery

BACKGROUND

A new hemostatic sealant based on a N-hydroxy-succinimide polyoxazoline (NHS-POx) polymer was evaluated to determine hemostatic efficacy and long-term wound healing and adverse effects in a large animal model of parenchymal organ surgical bleeds.

METHODS

Experiment 1 included 20 pigs that were treated with two NHS-POx patch prototypes [a gelatin fibrous carrier (GFC) with NHS-POx and an oxidized regenerated cellulose (ORC) with poly(lactic-co-glycolic acid)-NHS-POx:NU-POx (nucleophilically activated polyoxazoline)], a blank gelatin patch (GFC Blank), TachoSil^® and Veriset™ to stop moderate liver and spleen punch bleedings. After various survival periods (1-6 weeks), pigs were re-operated to evaluate patch degradation and parenchymal healing. During the re-operation, experiment 2 was performed: partial liver and spleen resections with severe bleeding, and hemostatic efficacy was evaluated under normal and heparinized conditions of the two previous prototypes and one additional NHS-POx patch. In the third experiment an improved NHS-POx patch (GATT-Patch; GFC-NHS-POx and added 20% as nucleophilically activated polyoxazoline; NU-POx) was compared with TachoSil^®, Veriset™ and GFC Blank on punch bleedings and partial liver and spleen resections for rapid (10s) hemostatic efficacy.

RESULTS

NHS-POx-based patches showed better (GFC-NHS-POx 83.1%, ORC-PLGA-NHS-POx: NU-POx 98.3%) hemostatic efficacy compared to TachoSil^® (25.0%) and GFC Blank (43.3%), and comparable efficacy with Veriset™ (96.7%) on moderate standardized punch bleedings on liver and spleen. All patches demonstrated gradual degradation over 6 weeks with a reduced local inflammation rate and an improved wound healing. For severe bleedings under non-heparinized conditions, hemostasis was achieved in 100% for Veriset™, 40% for TachoSil and 80-100% for the three NHS-POx prototypes; similar differences between patches remained for heparinized conditions. In experiment 3, GATT-Patch, Veriset™, TachoSil and GFC Blank reached hemostasis after 10s in 100%, 42.8%, 7.1% and 14.3%, respectively, and at 3 min in 100%, 100%, 14.3% and 35.7%, respectively, on all liver and spleen punctures and resections.

CONCLUSIONS

NHS-POx-based patches, and particularly the GATT-Patch, are fast in achieving effective hemostatic sealing on standardized moderate and severe bleedings without apparent long-term adverse events.

Intentional R1 resection of liver metastases: A new treatment paradigm for patients with advanced colorectal cancer based on a propensity score-Matched case-control analysis

BACKGROUND

Clinical outcomes of colorectal cancer (CRC) patients after an incomplete microscopic (R1) resection of liver metastases may not differ from those following a microscopically margin negative (R0) resection, when the latest is not feasible because of anatomic issues. We aimed at comparing the clinical outcomes of CRC patients with an intentional R1 or with a R0 resection of liver metastases.

METHODS

All patients with advanced in CRC and liver metastases consecutively treated by liver resection between February 2005 and January 2019 at in the department of Digestive and Hepatobiliary Surgery of Henri Mondor University Hospital (Créteil, France) were included in this retrospective case-control study. Overall survival (OS) and event-free survival (EFS) were compared between patients who underwent an intentional (pre-operative decision) R1 resection (iR1) to those who had a R0 resection of liver metastases. To account for confounding, comparison between the 2 groups was performed after adjustment using propensity score analysis.

RESULTS

Twenty-six CRC patients treated by iR1 resection of liver metastases were compared to 98 patients treated by R0 resection. Median OS reached 39 months [95% confidence interval (CI): 25-67] and 63 months [95% CI: 52-76] in the iR1 and R0 groups, respectively. After adjustment by inverse probability of treatment weighting, patients' OS and EFS did not differ significantly between the iR1 and R0 groups (hazard ratio (HR): 1.19 [0.54-2.62] and 1.67 [0.93-3.03]), respectively.

CONCLUSION

iR1 resection of liver metastases in advanced CRC patients is an acceptable therapeutic strategy, when R0 resection is not feasible.

Surgical Strategies for Combined Hepatocellular-Cholangiocarcinoma (cHCC-CC)

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a tumor entity presenting features of hepatocellular and cholangiocellular epithelial differentiation. Due to the likeness between cHCC-CC, HCC and CC, accurate pretherapeutical diagnosis is challenging and advanced stages are prevalent. Radical oncological surgery is the only curative therapeutical option in patients with cHCC-CC. To reach this goal a profound understanding of this rare liver tumor is crucial. Factors such as clinicopathological characteristics, growth patterns and biological behavior are of central importance. To explore onco-surgical strategies and aspects for complete resection of cHCC-CC and to answer important key questions, an extensive review of the literature was conducted to answer the following questions: What are the best surgical options? Is there a significance for nonanatomical resections? Is there a prognostic value of concomitant lymphadenectomy? What about multimodal concepts in local advanced cHCC-CC? The role of minimally invasive liver surgery (MILS) including the role of robotic liver surgery for cHCC-CC will be discussed. While liver transplantation (LT) is standard for patients with unresectable HCC, the role of LT in cHCC-CC patients is still controversial. How can patients with high risk for early tumor recurrence be identified to avoid aggressive surgical treatment without clinical benefit? The comprehensive understanding of this challenging liver tumor will help to improve future treatment options for these patients.

Mini-ALPPS-based multidisciplinary treatment leading to long-term survival in a patient with a large HCC: A case report

Background

The future liver remnant (FLR) induced by stage I associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) in hepatocellular carcinoma (HCC) might be limited due to liver fibrosis/cirrhosis or incomplete liver parenchymal transection.

Case presentation

A 51-year-old male with hepatitis B liver fibrosis was diagnosed with a large HCC (13.5 cm × 12.5 cm × 13.8 cm). The FLR of the patient was insufficient to permit one-stage tumor resection. Therefore, the two-stage ALPPS surgery was planned. Stage I ALPPS was performed with incomplete liver parenchymal transection due to bleeding (which is why we called it Mini-ALPPS). On postoperative day (POD) 18, CT revealed that the FLR hypertrophy was poor. The FLR/standard liver volume (SLV) had only increased from 22.00% to 34.63%. Salvage transhepatic arterial chemoembolization (TACE) was performed on POD 22 days to control possible tumor progression during the waiting period and to further facilitate FLR growth. About 16 days later, a CT reassessment of FLR revealed a 42.5% FLR/SLV. A right hepatectomy was then uneventfully performed. Although HCC recurred after 586 days, the patient survived for more than 1,920 days after stage II ALPPS.

Discussion

Damage control during a difficult conventional stage I ALPPS was important. TACE during the interstage and postoperative periods of this Mini-ALPPS was safe and beneficial. A multidisciplinary based on Mini-ALPPS treatment could provide patients long-term survival; however, Mini-ALPPS should not be selected as the primary solution for such patients today, as some other minimally invasive and effective strategies are available.