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

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.

Current Perspectives and Progress in Preoperative Portal Vein Embolization with Stem Cell Augmentation (PVESA)

Portal vein embolization with stem cell augmentation (PVESA) is an emerging approach for enhancing the growth of the liver segment that will remain after surgery (i.e., future liver remnant, FLR) in patients with liver cancer. Conventional portal vein embolization (PVE) aims to induce preoperative FLR growth, but it has a risk of failure in patients with underlying liver dysfunction and comorbid illnesses. PVESA combines PVE with stem cell therapy to potentially improve FLR size and function more effectively and efficiently. Various types of stem cells can help improve liver growth by secreting paracrine signals for hepatocyte growth or by transforming into hepatocytes. Mesenchymal stem cells (MSCs), unrestricted somatic stem cells, and small hepatocyte-like progenitor cells have been used to augment liver growth in preclinical animal models, while clinical studies have demonstrated the benefit of CD133 + bone marrow-derived MSCs and hematopoietic stem cells. These investigations have shown that PVESA is generally safe and enhances liver growth after PVE. However, optimizing the selection, collection, and application of stem cells remains crucial to maximize benefits and minimize risks. Additionally, advanced stem cell technologies, such as priming, genetic modification, and extracellular vesicle-based therapy, that could further enhance efficacy outcomes should be evaluated. Despite its potential, PVESA requires more investigations, particularly mechanistic studies that involve orthotopic animal models of liver cancer with concomitant liver injury as well as larger human trials.

Beyond the Horizon: Unveiling the Frontiers of Rectal Cancer Research and Treatment

Colorectal cancer, ranking among the most prevalent causes of cancer-related mortality, is an escalating global health concern. The incidence and mortality of colorectal cancer are expected to surge substantially by 2030, posing a significant public health challenge. This article provides a comprehensive overview of rectal cancer, encompassing its epidemiology, anatomical intricacies, pathophysiology, clinical presentation, and diagnosis. The tumor-node-metastasis (TNM) classification system for rectal cancer is detailed, offering crucial insights for staging and treatment decisions. Various treatment modalities are discussed, including surgical approaches, systemic therapies, radiation therapy, and local therapies for metastases. Recent advances in robotic surgery and innovative radiation technologies are explored. Furthermore, prevention strategies are elucidated, focusing on lifestyle modifications and pharmacological interventions that may mitigate the risk of colorectal cancer. The article underscores the importance of understanding rectal cancer for healthcare professionals and patients, enabling informed decision-making and enhanced management of this disease. Prognostic factors are outlined, with survival rates and the prognosis of rectal cancer contingent on several influential elements, highlighting the multifaceted nature of this condition. In conclusion, accurate diagnosis, diverse treatment options, and prevention strategies, including advances like robotic surgery, influence rectal cancer outcomes. A comprehensive overview empowers healthcare professionals and patients to make informed decisions for improved disease management and prognosis.

The Effect of Microwave and Radiofrequency Ablation (MWA/RFA) on Liver Volume in Patients with Primary and Secondary Liver Tumours: A Retrospective Analysis

PURPOSE

It is known that thermal liver ablation can induce liver hypertrophy. However, exact impact in liver volume remains unclear. The aim of this study is to assess the influence of radiofrequency or microwave ablation (RFA/MWA) on liver volume in patients with primary and secondary liver lesions. Findings can be relevant in assessing the potential extra benefit of thermal liver ablation in preoperatively performed liver hypertrophy inducing procedures, such as portal vein embolization (PVE).

METHODS

Between January 2014-May 2022, 69 invasive treatment naïve patients with primary (n = 43) or secondary/metastatic (n = 26) liver lesions (in all segments, except in segments II/III) treated percutaneously by RFA/MWA were included. Total liver volume (TLV), segment II + III volume (serving as "distant liver volume"), ablation zone volume and absolute liver volume (ALV, calculated by subtracting the ablation zone volume from the TLV) were the study outcomes.

RESULTS

ALV in patients with secondary liver lesions increased to a median percentage of 106.87% (IQR = 99.66-113.03%, p = 0.016), volume of segments II/III increased to a median percentage of 105.81% (IQR = 100.06-115.65%, p = 0.003). ALV and segments II/III in patients with primary liver tumours remained stable, with a median percentage of 98.72% (IQR = 92.99-108.35%, p = 0.856) and 100.43% (IQR = 92.85-109.41%, p = 0.699), respectively.

CONCLUSION

In patients with secondary liver tumours, ALV and segments II/III increased after MWA/RFA by an average of approximately 6%, while ALV in patients with primary liver lesions remained unchanged. Besides the curative intent, these findings indicate the potential added benefit of thermal liver ablation on FLR hypertrophy inducing procedures in patients with secondary liver lesions.

LEVEL OF EVIDENCE

Level 3, non-controlled retrospective cohort study.

Selecting the Best Approach for the Treatment of Multiple Non-Metastatic Hepatocellular Carcinoma

According to the Barcelona Clinic Liver Cancer (BCLC) staging system, the optimal strategy for patients with multiple HCC within the Milan Criteria is liver transplantation (LT). However, LT cannot be offered to all the patients due to organ shortages and long waiting lists, as well as because of the advanced disease carrying a high risk of poor outcomes. For early stages, liver resection (LR) or thermal ablation (TA) can be proposed, while trans-arterial chemoembolization (TACE) still remains the treatment of choice for intermediate stages (BCLC-B). Asian guidelines and the National Comprehensive Cancer Network suggest LR for resectable multinodular HCCs, even beyond Milan criteria. In this scenario, a growing body of evidence shows better outcomes after surgical resection when compared with TACE. Trans-arterial radioembolization (TARE) and stereotaxic body radiation therapy (SBRT) can also play an important role in this setting. Furthermore, the role of minimally invasive liver surgery (MILS) specifically for patients with multiple HCC is still not clear. This review aims to summarize current knowledge about the best therapeutical strategy for multiple HCC while focusing on the role of minimally invasive surgery and on the most attractive future perspectives.