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

Precision in Liver Surgery: A Comparative Analysis of Volumetry Techniques

BACKGROUND

Future liver remnant volume (FLRV) is a critical determinant of safety for hepatectomy. This study assesses concordance between imaging-based measured FLRV (mFLRV), and body surface area (BSA)-based standardized FLRV (sFLRV), and their association with post-hepatectomy complications.

MATERIALS AND METHODS

All major hepatectomy between 1999 and 2021 were assessed for agreement between mFLRV and sFLRV using concordance correlation coefficient (CCC). Association between each method and major postoperative complications, post-hepatectomy liver failure (PHLF), or grade 4/5 morbidity was compared using logistic regression model and area under the receiver-operating characteristic (AUC) curve to evaluate the discriminatory power of each volumetry method separately.

RESULTS

A total of 1749 patients were included, 49% were female, median age was 60 years, 70.2% had metastatic disease, and 49.7% received preoperative chemotherapy. Median sFLRV (41.3%) was higher than mFLRV (39.4%). Major complications were observed in 5.1% (n = 90). Concordance between mFLRV and sFLRV was moderate, CCC = 0.78 (95% CI 0.75-0.79) but was poor (CCC = 0.39; 95% CI 0.32-0.43) among patients with mFLRV ≤ 35% (n = 528). In this subset, sFLRV overestimated remnant volume in 63% (n = 333) with ≥ 5% overprediction in 145 patients (27.5%). Factors associated with ≥ 5% variation were lower weight (p = 0.003), lower BMI (p = 0.003), and lower BSA (p = 0.004). Both methods performed similarly in predicting major complications with AUC of 0.64 and 0.63 for sFLRV and mFLRV, respectively.

CONCLUSIONS

Imaging- and BSA-based volumetry are moderately correlated, with poor concordance among patients with smaller FLRV where sFLRV overestimated remnant volume. Both techniques can be safely used for volumetric assessment before major hepatectomy.

Associations of KRAS Point Mutations with Survival of Patients Who Underwent Curative-Intent Resection of Colorectal Liver Metastases

BACKGROUND

The oncologic significance of specific KRAS point mutations for patients with colorectal liver metastases (CLM) is uncertain. This study aimed to assess the prognostic impact of KRAS point mutations on patients who underwent surgery for CLM.

METHODS

Patients who underwent curative-intent surgery for CLM from 2001 to 2020 were selected for the study. In the study, KRAS point mutations and other clinicopathologic variables were examined for association with survival.

RESULTS

The study classified 798 patients into five groups by KRAS mutation status as follows: wild-type (n = 412, 51.6%), G12D (n = 123, 15.4%), G12V (n = 88, 11.0%), G13D (n = 61, 7.6%), and "Other" mutations (n = 114, 14.3%). For the patients with G12V substitutions, TP53 mutation was associated with worse overall survival (OS) (hazard ratio [HR], 2.64; 95% confidence interval [CI], 1.04-6.66; P = 0.041), but was not associated with a survival difference for the other four groups. The patients with co-occurring KRAS G12V and TP53 had a median OS of 4.4 years and a 5-year OS rate of 39.8%. In contrast, the patients with KRAS G12V mutation and wild-type TP53 had a median OS of 7.3 years and a 5-year OS rate of 75.9%, similar to the corresponding values for the patients with wild-type KRAS. Co-occurring KRAS G12V and TP53 mutations were independently associated with worse OS in the entire cohort (HR, 2.08; 95% CI, 1.15-3.76; P = 0.015).

CONCLUSIONS

This study showed that KRAS G12V mutation is associated with worse OS for patients undergoing curative-intent CLM resection, but only those with co-occurring TP53 mutation. Prognosis after surgery for CLM should not be stratified by KRAS mutation site alone.

A Systematic Review and Meta-Analysis of Oncologic Liver Resections in Low- and Middle-Income Countries: Opportunities to Improve Evidence and Outcomes

BACKGROUND

Patients in low- and middle-income countries (LMICs) are disproportionately affected by liver cancers but there is a lack of understanding of their postoperative outcomes. This study aimed to review the current status of research in LMICs regarding outcomes after oncologic hepatectomy and synthesize the data reported in the literature.

METHODS

The PubMed, Scopus, Embase, Web of Science, and World Health Organization (WHO) Global Index Medicus databases were searched from database inception to May 26th, 2022. Studies that reported outcomes after oncologic hepatectomy in LMIC settings were eligible for inclusion. Two independent reviewers performed record screening and data extraction. Risk of bias assessment was performed using the National Institutes of Health Study Quality Assessment tools. Pooled results with 95% confidence intervals (95% CIs) were calculated using a random effects model.

RESULTS

One hundred and thirty-five studies and 16 985 patients were included. Most studies were of a "fair" quality. Two studies described pediatric patients. Only one study was from a low-income country and most African regions were not represented. The rates of major and minor complications were 11% and 27%, respectively, while 30- and 90-day mortality rates were 2% and 3% each. Postoperative liver failure (8%), surgical site infections (6%), and bile leaks (6%) were common complications.

CONCLUSIONS

This review indicates a dearth of data from LMICs on outcomes after hepatectomy, particularly from African regions and low-income countries.

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.

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.

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.

The assessment of impaired liver function and prognosis in hepatocellular carcinoma

INTRODUCTION

The impairment of liver function strongly limits the therapeutic options for hepatocellular carcinoma (HCC), and the assessment of liver function is key to finding the appropriate therapy for patients suffering from this disease. Furthermore, preexisting liver dysfunction has a negative impact on the prognosis of patients in addition to the malignant potential of HCC. Hence, defining the optimal treatment of patients with HCC requires a comprehensive examination with liver function being a crucial part of it.

AREAS COVERED

This review will provide an overview of the currently existing methods for evaluating the liver function in patients with HCC. Assessment of liver function includes scoring systems but also functional and technical methods. In addition, the role of these tests in different treatment facilities such as liver resection, transplantation, interventional and systemic therapy is summarized.

EXPERT OPINION

A comprehensive pretherapeutic assessment of the liver function includes laboratory-based scoring systems, as well as imaging- and non-imaging-based functional tests. Combining diverse parameters can help to improve the safety and efficacy of HCC therapy particularly in patients with compromised liver function. Future research should focus on optimizing pretherapeutic assessment recommendations for each therapy.