Anatomical Quantitative Volumetric Evaluation of Liver Segments in Hepatocellular Carcinoma Patients Treated with Selective Internal Radiation Therapy: Key Parameters Influencing Untreated Liver Hypertrophy

Background: Factors affecting morphological changes in the liver following selective internal radiation therapy (SIRT) are unclear, and the available literature focuses on non-anatomical volumetric assessment techniques in a lobar treatment setting. This study aimed to investigate quantitative changes in the liver post-SIRT using an anatomical volumetric approach in hepatocellular carcinoma (HCC) patients with different levels of treatment selectivity and evaluate the parameters affecting those changes. This retrospective, single-institution, IRB-approved study included 88 HCC patients. Whole liver, liver segments, tumor burden, and spleen volumes were quantified on MRI at baseline and 3/6/12 months post-SIRT using a segmentation-based 3D software relying on liver vascular anatomy. Treatment characteristics, longitudinal clinical/laboratory, and imaging data were analyzed. The Student's t-test and Wilcoxon test evaluated volumetric parameters evolution. Spearman correlation was used to assess the association between variables. Uni/multivariate analyses investigated factors influencing untreated liver volume (uLV) increase. Results: Most patients were cirrhotic (92%) men (86%) with Child-Pugh A (84%). Absolute and relative uLV kept increasing at 3/6/12 months post-SIRT vs. baseline (all, p ≤ 0.005) and was maximal during the first 6 months. Absolute uLV increase was greater in Child-Pugh A5/A6 vs. ≥B7 at 3 months (A5, p = 0.004; A6, p = 0.007) and 6 months (A5, p = 0.072; A6, p = 0.031) vs. baseline. When the Child-Pugh class worsened at 3 or 6 months post-SIRT, uLV did not change significantly, whereas it increased at 3/6/12 months vs. baseline (all p ≤ 0.015) when liver function remained stable. The Child-Pugh score was inversely correlated with absolute and relative uLV increase at 3 months (rho = -0.21, p = 0.047; rho = -0.229, p = 0.048). In multivariate analysis, uLV increase was influenced at 3 months by younger age (p = 0.013), administered 90Y activity (p = 0.003), and baseline spleen volume (p = 0.023). At 6 months, uLV increase was impacted by younger age (p = 0.006), whereas treatment with glass microspheres (vs. resin) demonstrated a clear trend towards better hypertrophy (f = 3.833, p = 0.058). The amount (percentage) of treated liver strongly impacted the relative uLV increase at 3/6/12 months (all f ≥ 8.407, p ≤ 0.01). Conclusion: Liver function (preserved baseline and stable post-SIRT) favored uLV hypertrophy. Younger patients, smaller baseline spleen volume, higher administered 90Y activity, and a larger amount of treated liver were associated with a higher degree of untreated liver hypertrophy. These factors should be considered in surgical candidates undergoing neoadjuvant SIRT.

Partial liver irradiation in rats induces the hypertrophy of nonirradiated liver lobes through hepatocyte proliferation†

Irradiation of the liver induces a regenerative response in the nonirradiated part of the liver. It is unclear whether this leads to actual liver enlargement. The aim of this study was to evaluate the weight of compensatory hypertrophy that occurs in nonirradiated livers and to clarify the mechanism of hypertrophy from the viewpoint of hepatocyte proliferation. The anterior liver lobes (anterior lobes) were irradiated with 60 Gy of X-rays (X60 Gy) under opening laparotomy. Body weights and liver lobe weights were measured before and at 1, 4, 8 and 12 weeks after irradiation, and serum and liver tissue samples were analyzed at each time point. The anterior lobes atrophied progressively, whereas the posterior liver lobes (posterior lobes) hypertrophied in the X-ray irradiated (X-irradiated) group. Although temporary liver damage was observed after irradiation, liver function did not decrease at any time point. Hepatocyte degeneration and loss were observed in the anterior lobes of the X-irradiated group, and significant fibrosis developed 8 weeks postirradiation. Following irradiation, the proportion of Ki-67-positive cells in the anterior lobes decreased markedly in the early postirradiation period, whereas the proportion of positive cells in the posterior lobes increased, peaking at 4 weeks postirradiation (P < 0.05). Increased tumor necrosis factor-α expression was observed only in the anterior liver lobes of the X-irradiated group at 1 and 4 weeks postirradiation. Partial liver irradiation with X60 Gy induced compensatory hypertrophy of nonirradiated liver lobes. This study suggests that liver hypertrophy after partial liver irradiation is caused by increased hepatocyte mitosis.

Safety and Efficacy of Liver Venous Deprivation Following Transarterial Chemoembolization Before Major Hepatectomy for Hepatocellular Carcinoma

Objective

This study aimed to evaluate the safety and efficacy of liver venous deprivation (LVD) following transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC).

Methods

Between January 2021 and December 2022, HCC patients indicated for hepatectomy with initial insufficient future liver remnant (FLR) underwent LVD after TACE to induce preoperative liver hypertrophy.

Results

Twenty-seven HCC patients with a median age of 55 years underwent LVD. No TACE or LVD procedure-associated complications occurred, except for 1 case presenting with grade A liver failure after LVD (then recovered after 7 days). The FLR volume was 29.3% (interquartile range [IQR] = 7.5) and 48.9% (IQR = 8.6) of the total liver volume before and after LVD, respectively (p < 0.001). The degree of hypertrophy and FLR hypertrophy rate were 14.8% (IQR = 8.4) and 55.2% (IQR = 36.7), respectively. All 27 patients demonstrated sufficient FLR after LVD (24 patients at three weeks post-LVD, one at six weeks, and two at ten weeks), but only 21 patients accepted surgery. Postoperative histopathology showed 16 patients with cirrhosis and five with mild fibrosis (F1, F2). One patient presented with severe intraoperative bleeding due to damage of left hepatic vein and developed grade C liver failure, then died on day 32 postoperation.

Conclusion

LVD following TACE seems to be a safe, effective, and feasible method of inducing significant FLR regeneration in HCC, even in well-selected cirrhotic livers. Comparative studies with a large patient population and multicenter data are needed for further evaluation.

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

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

Significance of Skeletal Muscle Loss in Liver Hypertrophy in Patients Undergoing Portal Vein Embolization Before Major Hepatectomy: Assessment With Body Composition and Nutritional Indicators

BACKGROUND/AIM

The relationship between body composition including skeletal muscle and liver hypertrophy initiated by portal vein embolization (PVE) for major hepatectomy has not been clarified. This study aimed to investigate the effects of skeletal muscle, body adipose, and nutritional indicators on liver hypertrophy.

PATIENTS AND METHODS

Fifty-nine patients who underwent PVE scheduled for major right-sided hepatectomy were included. The skeletal muscle area of L3 as skeletal muscle index was calculated. The relationship between skeletal muscle loss and clinical variables was assessed. We also evaluated the relationship between >30% liver growth or >12% liver growth/week after PVE.

RESULTS

Skeletal muscle loss was observed in 39 patients (66.1%) and associated with zinc deficiency, visceral adipose index, liver growth rate, and liver growth rate/week. Multivariate analysis indicated that future liver volume and skeletal muscle index were associated with >30% liver growth, and functional future liver volume and skeletal muscle index were associated with >12% liver growth/week.

CONCLUSION

Loss of skeletal muscle, and a small future remnant liver volume, attenuates liver hypertrophy initiated by PVE. Strength building and nutritional supplementation may have positive effects on liver hypertrophy after PVE.

Reg3α and Reg3β Expressions Followed by JAK2/STAT3 Activation Play a Pivotal Role in the Acceleration of Liver Hypertrophy in a Rat ALPPS Model

To explore the underlying mechanism of rapid liver hypertrophy by liver partition in associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), liver partition at different sites was investigated. Increased inflammatory cytokines owing to the liver partition have been reportedly responsible. If this were true, rapid liver hypertrophy should be achieved regardless of where the liver was split. A male Sprague-Dawley rat model was created, in which a liver split was placed inside the portal vein ligated lobe (PiLL), in addition to the ALPPS and portal vein ligation (PVL) models. Liver regeneration rate, inflammatory cytokine levels, activation status of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and expressions of regenerating islet-derived (Reg)3α and Reg3β were investigated. The liver regeneration rate was significantly higher in the ALPPS group than in the PiLL group, whereas inflammatory cytokine levels were nearly equal. Additional volume increase in ALPPS group over PVL and PiLL groups was JAK2/STAT3-dependent. Reg3α and Reg3β expressions were observed only in the ALPPS group. An increase in inflammatory cytokines was not enough to describe the mechanism of rapid liver hypertrophy in ALPPS. Expressions of Reg3α and Reg3β could play an important role in conjunction with an activation of the JAK2/STAT3 pathway.

The Connection of Azole Fungicides with Xeno-Sensing Nuclear Receptors, Drug Metabolism and Hepatotoxicity

Azole fungicides, especially triazole compounds, are widely used in agriculture and as pharmaceuticals. For a considerable number of agricultural azole fungicides, the liver has been identified as the main target organ of toxicity. A number of previous studies points towards an important role of nuclear receptors such as the constitutive androstane receptor (CAR), the pregnane-X-receptor (PXR), or the aryl hydrocarbon receptor (AHR), within the molecular pathways leading to hepatotoxicity of these compounds. Nuclear receptor-mediated hepatic effects may comprise rather adaptive changes such as the induction of drug-metabolizing enzymes, to hepatocellular hypertrophy, histopathologically detectable fatty acid changes, proliferation of hepatocytes, and the promotion of liver tumors. Here, we present a comprehensive review of the current knowledge of the interaction of major agricultural azole-class fungicides with the three nuclear receptors CAR, PXR, and AHR in vivo and in vitro. Nuclear receptor activation profiles of the azoles are presented and related to histopathological findings from classic toxicity studies. Important issues such as species differences and multi-receptor agonism and the consequences for data interpretation and risk assessment are discussed.

Evaluation of segment 4 portal vein embolization added to right portal vein for right hepatic trisectionectomy: A retrospective propensity score-matched study

BACKGROUND

Adding segment 4 (S4) portal vein embolization (PVE) to right PVE before right hepatic trisectionectomy is controversial. We retrospectively examined the effect of S4 PVE on segments 2 and 3 (S2 + 3) hypertrophy.

METHODS

We reviewed patients with biliary carcinoma who underwent right PVE with (R3PVE) or without (R2PVE) S4 PVE using gelatin sponge particles and coils (2010-2019). Propensity score matching balanced the cohort for baseline characteristics, including total liver volume and S2 + 3 volume before PVE. We compared the groups regarding the S2 + 3 volume changes after PVE.

RESULTS

Of 178 enrolled patients, 38 underwent R3PVE for right hepatic trisectionectomy and 140 underwent R2PVE for right hepatectomy. Twenty-eight patients from each group were respectively matched. The median absolute volume increase in (146 cm³ vs 70 cm³ ), hypertrophy rate of (52.4% vs 32.3%), and kinetic growth rate of (3.1%/wk vs 2.0%/wk) S2 + 3 were significantly higher in the R3PVE group than in the R2PVE group. In the pre-matched cohort, the rate of posthepatectomy liver failure and postoperative hospital stay did not significantly differ between the patients who underwent right hepatic trisectionectomy and right hepatectomy.

CONCLUSION

R3PVE increased the S2 + 3 volume more effectively than R2PVE in patients with biliary carcinoma.

Construction of the Database of Rat Repeated-dose Toxicity Tests of Pesticides for the Toxicological Characterization of Hepatocyte Hypertrophy

Liver and hepatocyte hypertrophy can be induced by exposure to chemical compounds, but the mechanisms and toxicological characteristics of these phenomena have not yet been investigated extensively. In particular, it remains unclear whether the hepatocyte hypertrophy induced by chemical compounds should be judged as an adaptive response or an adverse effect. Thus, understanding of the toxicological characteristics of hepatocyte hypertrophy is of great importance to the safety evaluation of pesticides and other chemical compounds. To this end, we have constructed a database of potentially toxic pesticides. Using risk assessment reports of pesticides that are publicly available from the Food Safety Commission of Japan, we extracted all observations/findings that were based on 90-day subacute toxicity tests and 2-year chronic toxicity and carcinogenicity tests in rats. Analysis of the database revealed that hepatocyte hypertrophy was observed for 37-47% of the pesticides investigated (varying depending on sex and testing period), and that centrilobular hepatocyte hypertrophy was the most frequent among the various types of hepatocyte hypertrophy in both the 90-day and 2-year studies. The database constructed in this study enables us to investigate the relationships between hepatocyte hypertrophy and other toxicological observations/findings, and thus will be useful for characterizing hepatocyte hypertrophy.

Present status and future perspectives of ALPPS (associating liver partition and portal vein ligation for staged hepatectomy)

First International Consensus Meeting, Hamburg, Germany, 27-28 February 2015 More than 160 participants took part in the conference for 2 days. A total of 58 world renown experts on ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) were invited from all over the world. The faculty was divided into many different subgroups that were in contact during the 2-3 months before the conference analyzing all the most important aspects of this technique and summarizing it in a common structured work to be presented during the congress, giving final recommendations in the form of bulleted point statements. The aim was to gain a solid basis of preliminary agreement on many controversial aspects of ALPPS. A poster area was also organized with 35 posters reporting mostly mono-institutional experiences on single aspects of the technique from all five continents.

Radioembolization of hepatocellular carcinoma activates liver regeneration, induces inflammation and endothelial stress and activates coagulation

BACKGROUND & AIMS

Radioembolization may rarely induce liver disease resulting in a syndrome that is similar to veno-occlusive disease complicating bone marrow transplantation where inflammation, endothelial cell activation and thrombosis are likely involved. We hypothesized that similar mechanisms could be implicated in radioembolization-induced liver disease (REILD). Moreover, lobar radioembolization may induce hypertrophy of the non-treated hemiliver most probably by inducing liver regeneration.

METHODS

In patients with hepatocellular carcinoma, we prospectively studied serum levels of markers of liver regeneration, oxidative stress, pro-inflammatory pathways, endothelial activation and coagulation parameters over 2 months after radioembolization.

RESULTS

Although REILD did not occur among 14 treated patients, a decrease in effective liver blood flow was observed. Radioembolization was followed by a persistent increase in pro-inflammatory (interleukin 6 and 8) and oxidative stress (malondyaldehide) markers, an induction of endothelial injury markers (vW factor and PAI-1) and an activation of the coagulation cascade (factor VIII, PAI-1, D-Dimer) as well as a significant increase in factors related to liver regeneration (FGF-19 and HGF).

CONCLUSION

Radioembolization activates liver regeneration, produces oxidative stress, activates inflammatory cytokines and induces endothelial injury with partial activation of the coagulation cascade. These findings may have implications in the pathogenesis, prevention and therapy of REILD and in the development of new therapies to enhance hypertrophy with a surgical perspective.

Acute Thrombosis of Left Portal Vein during Right Portal Vein Embolization Extended to Segment 4

Portal vein thrombosis (PVT) is an uncommon, but potentially devastating complication of portal vein embolization (PVE). Its occurrence relates to both local and systemic risk factors. In the setting of PVE, precipitating factors include injury to the vessel wall and reduced portal flow. Contributory factors include portal hypertension, hypercoagulopathy, inflammatory processes, malignancy, pregnancy, oral contraceptive use, and asplenia. The goal of therapy is to prevent thrombus progression and lyse existing clot. Hepatectomy is impossible if adequate recanalization has not occurred and/or overt portal hypertension develops. The mechanisms for thrombus development, its diagnosis, management, and prognosis are discussed.

Percutaneous transhepatic portal vein embolization: rationale, technique, and outcomes

Portal vein embolization (PVE) is used to induce preoperative liver hypertrophy in patients with anticipated marginal future liver remnant (FLR) volumes who are otherwise potential candidates for resection. PVE can be performed utilizing the transhepatic contralateral and ipsilateral approaches. The transhepatic contralateral approach is the most commonly used technique worldwide, largely owing to its technical ease. However, the contralateral approach risks injuring the FLR, thereby compromising the planned surgical resection. The transhepatic ipsilateral approach offers a potentially safer alternative because the complications associated with this approach affect only the hepatic lobe that will be resected and are usually not serious enough to preclude surgery. This article discusses PVE using the transhepatic ipsilateral and contralateral approaches, including patient selection criteria, anatomical and technical considerations, and patient complications and outcomes.

Hypertrophy of the non-embolized liver after chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NC(+)) and portal vein embolization (PVE) enables curative resection in more patients with colorectal-liver metastases (CRLM). However, after NC(+), structural alterations have been reported with the risk of post-operative hepatic failure. We undertook to determine if NC(+) toxicity limits future remnant liver (FRL) hypertrophy after PVE.

METHODS

PVE was performed in 20 patients, 13 (65%) of whom previously received a mean FOLFIRI (5-fluorouracil + leucovorin + irinotecan) regimen (NC(+)) of 6.6 cycles. The seven remaining patients served as the control group without NC (NC(-)).

RESULTS

CRLM were bilateral in 69% (NC(+)) and 57% (NC(-)), and synchronous in 84% (NC(+)) and 14% (NC(-)). The FRL hypertrophy rate was 54.1% (NC(+)) and 43.7% (NC(-)) (P= 0.3). CRLM were unresectable in four of our 20 patients, i.e. group NC(+): one insufficient FRL hypertrophy and one severe steatosis; and group NC(-): two tumoral progressions. In both groups, the operative parameters were comparable except for pedicular clamping: 8 (NC(+)) and 36 min (NC(-)), respectively (P < 0.05). Also, the surgical outcome rate and hospital stay were comparable. No significant pathological difference was observed between the two groups. No mortality occurred in either group.

CONCLUSION

In view of our limited experience, we conclude that hypertrophy of the non-embolized liver (FRL) is not altered after FOLFIRI-based NC.

Two-stage hepatectomy (R0) with portal vein ligation--towards curing patients with extended bilobular colorectal liver metastases

BACKGROUND AND AIMS

Patients with bilobular colorectal liver metastases (CRLM) experience poor prognosis, especially when curative resection cannot be achieved. However, resectability in these patients is often limited by low future remnant liver volume (FRLV). The latter can be enhanced by a two-stage liver resection, using portal vein ligation to induce liver hypertrophy. The aim of this prospective pilot study was to evaluate safety, secondary resectability, and time to recurrence of two-stage hepatectomy with portal vein ligation (PVL) and complete surgical clearance of the FRLV in patients with bilobular CRLM.

MATERIALS AND METHODS

Out of 24 patients (63+/-8.26 years) with extended bilobular CRLM (metachronous n=10, synchronous n=14), 18 received preoperative 5-FU-based chemotherapy combined with oxaliplatin or irinotecan. Staging included thoracoabdominal computed tomography and (18)F-fluorodeoxyglucose-positron emission tomography scans. First-stage procedure consisted of PVL, resection of all CRLM in the FRLV, and radiofrequency ablation (RFA) of CRLM situated near the future resection plane.

RESULTS

During first-stage procedure, 7x RFA, 4x non-anatomical resections, and 4x bisegmentectomies were performed additionally to PVL. FRLV/body-weight ratio increased from 0.4% to 0.6% within 55 days (median) after PVL. Second-stage hepatectomy was performed in 19 patients without tumor progression. R0 resection was possible in 14 patients. During a median follow-up of 17 months, intrahepatic recurrence occurred in two, and extrahepatic recurrence in nine out of 14 patients.

CONCLUSION

Two-stage hepatectomy with PVL and complete surgical clearance of FRLV is safe even after intensified systemic chemotherapy resulting in a curative resection rate of 58.3% (73.7% of re-explored cases).