Effect of partial liver resection on tumour growth

Anterior approach for right hepatectomy with hanging maneuver for hepatocellular carcinoma: a multi-institutional propensity score-matching study

BACKGROUND

This multi-institutional study aimed to assess the benefits of anterior approach for right hepatectomy with hanging maneuver (ARH-HM) for hepatocellular carcinoma (HCC) compared with conventional right hepatectomy (CRH).

METHODS

From January 2000 to December 2012, 306 patients with HCC ≥5 cm were divided into two groups: ARH-HM (n = 104) and CRH (n = 202).

RESULTS

After one-to-one propensity score-matched analysis, 72 ARH-HM and 72 CRH patients presented comparable background factors. Patients in the ARH-HM group demonstrated significantly less intraoperative blood loss (480 vs. 1,242 g, P < 0.001) and a lower frequency of red cell concentrate transfusion (21.1% vs. 50.7%, P < 0.001) compared with patients in the CRH group. The 5-year overall survival rate was significantly better in the ARH-HM group compared with the CRH group (50.2% vs. 31.4%, P = 0.021). Limited to patients with HCC ≥10 cm, recurrence-free and overall survival of the ARH-HM group was significantly greater than those of the CRH group.

CONCLUSION

In comparison with CRH, ARH-HM for large HCC can provide better overall survival rates with a decrease in intraoperative blood loss and transfusion rates. Survival impact was evident especially in patients with HCC ≥10 cm.

Effect of liver regeneration on malignant hepatic tumors

Liver regeneration after major surgery may activate occult micrometastases and facilitate tumor growth, leading to liver tumor recurrence. Molecular changes during liver regeneration can provide a microenvironment that stimulates intrahepatic tumor propagation through alterations in cellular signaling pathways, where activation and proliferation of mature hepatocytes, hepatic progenitor cells, non-parenchymal liver cells might favor both liver regeneration and tumor growth. This review highlights recent advances of tumor growth and development in the regenerating liver, possible mechanisms and clinical implications.

The role of hepatic ischemia-reperfusion injury and liver parenchymal quality on cancer recurrence

Hepatic ischemia/reperfusion (I/R) injury is a common clinical challenge. Despite accumulating evidence regarding its mechanisms and potential therapeutic approaches, hepatic I/R is still a leading cause of organ dysfunction, morbidity, and resource utilization, especially in those patients with underlying parenchymal abnormalities. In the oncological setting, there are growing concerns regarding the deleterious impact of I/R injury on the risk of post-surgical tumor recurrence. This review aims at giving the last updates regarding the role of hepatic I/R and liver parenchymal quality injury in the setting of oncological liver surgery, using a "bench-to-bedside" approach. Relevant medical literature was identified by searching PubMed and hand scanning of the reference lists of articles considered for inclusion. Numerous preclinical models have depicted the impact of I/R injury and hepatic parenchymal quality (steatosis, age) on increased cancer growth in the injured liver. Putative pathophysiological mechanisms linking I/R injury and liver cancer recurrence include an increased implantation of circulating cancer cells in the ischemic liver and the upregulation of proliferation and angiogenic factors following the ischemic insult. Although limited, there is growing clinical evidence that I/R injury and liver quality are associated with the risk of post-surgical cancer recurrence. In conclusion, on top of its harmful early impact on organ function, I/R injury is linked to increased tumor growth. Therapeutic strategies tackling I/R injury could not only improve post-surgical organ function, but also allow a reduction in the risk of cancer recurrence.

Increased growth of colorectal liver metastasis following partial hepatectomy

Nearly 50 % of colorectal cancer (CRC) patients develop liver metastases with liver resection being the only option to cure patients. Residual micrometastases or circulating tumor cells are considered a cause of tumor relapse. This work investigates the influence of partial hepatectomy (PH) on the growth and molecular composition of CRC liver metastasis in a syngeneic rat model. One million CC531 colorectal tumor cells were implanted via the portal vein in WAG/Rij rats followed by a 30 % PH a day later. Control groups either received tumor cells followed by a sham-operation or were injected with a buffer solution followed by PH. Animals were examined with magnetic resonance imaging (MRI) and liver tissues were processed for immunolabeling and PCR analysis. One-third PH was associated with an almost threefold increase in relative tumor mass (MRI volumetry: 2.8-fold and transcript levels of CD44: 2.3-fold). Expression of molecular markers for invasiveness and aggressiveness (CD49f, CXCR4, Axin2 and c-met) was increased following PH, however with no significant differences when referring to the relative expression levels (relating to tumor mass). Liver metastases demonstrated a significantly higher proliferation rate (Ki67) 2 weeks following PH and cell divisions also increased in the surrounding liver tissue. Following PH, the stimulated growth of metastases clearly exceeded the compensation in liver volume with long-lasting proliferative effects. However, the distinct tumor composition was not influenced by liver regeneration. Future investigations should focus on the inhibition of cell cycle (i.e. systemic therapy strategies, irradiation) to hinder liver regeneration and therefore restrain tumor growth.

Use of bioluminescence imaging to detect enhanced hepatic and systemic tumor growth following partial hepatectomy in mice

BACKGROUND

The impact of partial hepatectomy on intra-hepatic and distant tumor growth is a matter of controversy. Utilizing a highly sensitive tumor imaging strategy, we sought to demonstrate whether this growth-acceleration occurs, and to develop an animal model with which to investigate potential therapeutic strategies.

METHODS

Mice bearing constitutively-active luciferase-expressing tumor cells were subjected to either 70% partial hepatectomy (PH; n=10) or a sham operation (n=11). Mice were sacrificed 14 days later and remnant livers (or anatomic equivalents in the control group) and lungs harvested for bioluminescence detection.

RESULTS

Remnant liver weights were significantly increased in PH compared to equivalent lobes in sham-operated animals (t-test; p=0.005). Tumor burden as measured by bioluminescence was significantly higher in both liver and lung specimens in the PH group (Wilcoxon's Rank Sum test; p=0.01 and 0.004, respectively).

CONCLUSIONS

Following PH, enhanced metastatic growth was depicted regionally and systemically with bioluminescence imaging providing an objective measure of tumor burden. This preclinical model can help to identify adjuvant therapies that can influence both tumor growth and liver regeneration.

Review article: Multimodality treatment of liver metastases increases suitability for surgical treatment

BACKGROUND

Liver metastases of colorectal cancer occur frequently, but only 10-20% are eligible for liver surgery. Recent new developments changed the concepts of treating patients with colorectal liver metastases.

AIM

To describe the available modalities that can result in increasing resectability rate.

METHODS

Potentials and drawbacks of portal vein embolization, radiofrequency ablation (RFA), trans-ablated tumour hepatectomy, neoadjuvant chemotherapy and the approach to patients with extrahepatic metastases are described.

RESULTS

Portal vein embolization is a well-established technique to increase the volume of the future liver remnant. RFA should be applied if partial liver resection alone cannot make the liver tumour-free. Neoadjuvant chemotherapy in patients with unresectable liver metastases can result in secondary resectability rates of 15-40%. Hepatotoxicity can lead to a higher complication rate after partial liver resection. A limited number of extrahepatic tumour localizations should be resected as well.

CONCLUSIONS

A more aggressive approach to patients with colorectal liver metastases improves resectability rate and survival. Unfortunately, these new options have not been thoroughly evaluated in randomized controlled trials. For some of these modalities, the currently available results are so promising that it might be difficult to start such trials in the future.

Serum Endostatin Levels and Regenerative Capacities of Normal and Cirrhotic Livers Following Partial Hepatectomy in Mice: The Response to Different Resection Sizes

BACKGROUND

Angiogenesis has an important role in liver regeneration. Antiangiogenic response in remnant liver following resection and its relationship to regeneration is not well known. The aim of this study was to investigate the effect of hepatectomy size on serum endostatin levels, and the effect of endostatin levels to liver regeneration after partial hepatectomy in normal and cirrhotic mice.

MATERIALS AND METHODS

Sixty noncirrhotic and 36 carbon tetrachloride-induced cirrhotic mice were included in the study. Noncirrhotic mice were randomly divided into four main groups: sham, 20%, 40%, and 70% hepatectomy groups. Similarly, cirrhotic mice were randomly divided into three main groups: sham, 20%, and 40% hepatectomy groups. The mice in each group were further divided into two subgroups to compare serum endostatin levels and liver regeneration indexes on days 1 and 14. Liver regeneration was evaluated by the proliferating cell nuclear antigen-labeling index. Serum endostatin level was measured to evaluate antiangiogenic response.

RESULTS

Serum endostatin levels on the first day and 14th day increased significantly in correlation with the hepatectomy size, both in normal mice and cirrhotic mice (P < 0.05). In normal mice with high regeneration indexes that underwent 40% and 70% hepatectomies, there was a significant increase in serum endostatin levels on the 14th day compared with the first day (P < 0.05). However, the increase in mice that underwent 20% hepatectomies was not significant. After 20% and 40% hepatectomies, first day serum endostatin levels were significantly higher in cirrhotic mice compared with normal mice (P < 0.05), which was independent of regeneration. Nevertheless, after 40% hepatectomies, 14th day serum endostatin levels were significantly lower in cirrhotic mice compared with normal mice, attributable to the limited regeneration capacity of cirrhotic liver (P < 0.05). Regeneration capacity of cirrhotic liver was low at all times.

CONCLUSIONS

The current study suggests that there is a significant relationship between serum endostatin levels and regeneration capacity after hepatectomy in normal mice. On the other hand, following resection of cirrhotic liver, regeneration capacity is depressed and high endostatin levels are independent of hepatic regeneration.

Hepatic resection but not radiofrequency ablation results in tumor growth and increased growth factor expression

OBJECTIVE

The purpose of this study was to examine the effects of radiofrequency ablation (RFA) on tumor growth and growth factor expression in a murine model.

BACKGROUND

Surgical excision remains the only potentially curative therapy for hepatic malignancies. Tumor growth in the remaining liver may be accelerated after resection. The mechanism of this enhanced tumor growth remains unexplained, although growth factors that are released after hepatic resection (which facilitate liver regeneration) may play a role in residual tumor growth. RFA has become a viable alternative for patients who are not candidates for a curative resection. The effect of RFA on tumor growth and growth factor expression has not been studied.

METHODS

Hepatic tumors were established by direct injection with CT-26, a murine adenocarcinoma. Tumors were treated by either partial hepatic resection (PH) or RFA. Hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) expression was measured at selected time intervals post-treatment. Tumor growth was measured by reinjection of CT-26 into the residual liver after treatment. Nine days after reinjection, tumor volume was calculated and compared with nontreated controls.

RESULTS

HGF and bFGF expression was significantly higher at baseline in the CT-26 tumor-bearing mice when compared with non-tumor-bearing controls (P = 0.00001 and P = 9 x 10, respectively). There was an increase in HGF and bFGF expression at 24 hours (P = 0.005, and P = 0.001) in the PH group. In the RFA group, there was a decrease in HGF and bFGF expression at 24 and 72 hours (P = 0.001 and P = 0.002). Tumor growth comparisons revealed an increase in tumor growth in the hepatectomy group (P = 0.006) but not the RFA group (P = 0.2).

CONCLUSIONS

Baseline growth factor expression in tumor-bearing mice is exponentially higher when compared with non-tumor-bearing controls. HGF and bFGF expression are increased posthepatectomy, and decreased post-RFA. Partial hepatectomy results in an increase in tumor growth in the residual liver. RFA did not increase tumor growth after treatment. While hepatectomy is the only curative option for patients with hepatic malignancies, it may accelerate growth of microscopic residual disease.

Liver regeneration stimulates tumor metastases

BACKGROUND

Partial hepatectomy for patients with colorectal liver metastases is associated with a tumor recurrence rate approaching 80% post-resection. Different factors and phases associated with regeneration of the liver are implicated in tumor recurrence. This study investigates the effects of the early and late phases of liver regeneration and the impact of the degree of liver resection on stimulating tumor growth and metastasis.

MATERIALS AND METHODS

Groups of mice underwent partial hepatectomy (37% or 70%) and were then challenged with colorectal liver carcinoma (CRC) tumors immediately after liver resection (early and late phase effect) or 6 days post liver resection (late phase effect). Tumor growth, degree of proliferation, tumor morphology, and the presence of extrahepatic metastases were investigated 21 days post-tumor induction.

RESULTS

The late phase of liver regeneration plays a significant role in tumor stimulation and metastasis. The degree of hepatectomy also appears to be an important factor. The degree of hepatic resection significantly influences tumor growth and the extent of extrahepatic metastases, particularly in the lungs.

CONCLUSIONS

Elucidation of the processes involved in the late phase of liver regeneration may assist in the development and timing of adjuvant agents to minimize tumor recurrence during this phase.

Biology of colorectal liver metastases: A review

Metastatic growth is a selective, non-random process, which in the case of colorectal cancer, frequently occurs in the liver and is the major cause of cancer related death in these patients. This review summarises attempts to find biological and molecular markers of metastasis and their role in establishment of secondary tumours. Recent evidence suggests that liver metastases are phenotypically different to the primary from which they were derived and thus represent a separate disease entity.

Portal vein ligation and partial hepatectomy differentially influence growth of intrahepatic metastasis and liver regeneration in mice

BACKGROUND/AIMS

Since modern treatment of liver metastases includes serial hepatectomies and portal vein obstruction, we investigated the effects of portal vein ligation (PVL) and partial hepatectomy (PH) on tumor growth.

METHODS

The effects of 70% PH and PVL on liver and lung metastases were evaluated in mice. Tumor growth and liver regeneration were assessed by morphometry and immunohistochemistry for PCNA and BrdU. The effect of growth factors of liver regeneration on CT-26 cells was tested in vitro, and TGF-beta secretion of CT-26 cells was measured by ELISA. RNA synthesis of TGF-beta and activin A was measured by RT-PCR.

RESULTS

Liver regeneration after PH and PVL was similar in tumor-free mice. Intrahepatic tumor growth was lower after PH than after PVL (p=0.016). Extrahepatic tumor growth was not different. In contrast to PVL, liver regeneration was delayed after PH in metastatic livers (p=0.001). Tested growth factors of liver regeneration stimulated CT-26 cells in vitro, and CT-26 secreted significant amounts of TGF-beta in vitro and in vivo.

CONCLUSIONS

Although similar in tumor-free mice, liver regeneration significantly differed between PVL and PH in metastatic livers. In addition, PH and PVL differently affected intrahepatic tumor growth.

Surgery and angiogenesis

Surgery may be regarded as an angiogenesis-inducing condition since it evokes the release of many angiogenic factors. Regarding the mechanistic overlap between tumor-associated neovascularisation and (physiological) angiogenesis in response to injury and hypoxia, surgery may promote the uncontrolled growth of residual dormant tumor cells. With the advent of anti-angiogenic agents, surgeons will be faced with more patients undergoing surgery for primary and secondary tumors under anti-angiogenic treatment. This could present problems with regard to angiogenesis-dependent phenomena such as wound repair, healing of intestinal anastomoses and liver regeneration. In this review we will discuss these matters from a biomedical and clinical point of view.

Interstitial laser hyperthermia and the biological characteristics of tumor: study in a murine model of colorectal liver metastases

BACKGROUND DATA

Percutaneously applied interstitial laser hyperthermia (ILH) is a minimally invasive therapy that is currently used in the treatment of liver metastases. Despite its documented efficacy, theoretical considerations and evidence based on animal studies suggest the potential for stimulating tumor growth, especially following surgery. This study investigates the influence of ILH on tumor behaviour in an animal model of colorectal liver metastases.

MATERIALS AND METHODS

A model of colorectal cancer liver metastases in male inbred CBA mice was used. Laser hyperthermia was applied to tumor tissue using a bare optical quartz from a Medilas fibertom 4100 Nd:YAG surgical laser generator. Liver injury by ILH was initially produced in three experimental groups of animals at different time points in the development of metastases. ILH was applied (i) to normal liver 10 days prior to tumor induction, (ii) immediately prior to tumor induction, and (iii) 15 days after tumor induction to achieve approximately 8% liver destruction. Animals were killed 21 days after tumor induction, and the effects of ILH on overall tumor development were compared with controls using stereological assessment of tumor volume and by histology. In a separate experimental group, the effects of ILH on fully established tumors were examined. Suitable tumors were selected 21 days after induction and partially destroyed by ILH at a standard energy setting. Animals were then killed 15 days later, and the growth rate of the residual viable tumors was compared to control tumors having undergone sham procedures.

RESULTS

No significant stimulation of tumor growth was evident in any of the experimental groups following ILH, irrespective of the time of application. Incomplete tumor destruction also had no influence on subsequent tumor growth.

CONCLUSION

ILH does not influence the biological characteristics of tumors during any stage of the metastatic process.

The molecular physiology of liver regeneration following partial hepatectomy

The ability of the liver to regenerate after resection has been known for many years. Two reports from Germany in the late 1800s probably mark the introduction of the phenomenon into the scientific literature, but in the early 1900s the first reviews of this subject had appeared in the English literature. Predating these early scientific reports the legends from the Greek mythology described the fate of Prometheus. As punishment for defying Zeus and revealing the secret of fire to man, Prometheus was chained to a rock and each day had part of his liver ripped out by an eagle which, returning the following day, repeated the torture because his liver regenerated itself overnight. Although the speed of regeneration in the Greek legend is somewhat greater than that observed either clinically or in the laboratory, the myth does serve to emphasise the remarkable ability of the liver to repeatedly regenerate following repeated resections. This review aims to summarise the more recent literature concerning the early molecular events accompanying liver regeneration and to integrate this with the existing knowledge of this subject.

Serum response of hepatocyte growth factor, insulin-like growth factor-I, interleukin-6, and acute phase proteins in patients with colorectal liver metastases treated with partial hepatectomy or cryosurgery

BACKGROUND/AIMS

The aim of the study was to compare the serum response of regeneration factors and acute phase proteins in patients treated with partial hepatectomy or cryosurgery.

METHODS

The responses of serum hepatocyte growth factor (HGF), insulin-like growth factor-I (IGF-I) (free and total), interleukin-6 (IL-6) and the acute phase proteins, C-reactive protein (CRP) and serum amyloid A (SAA) were examined in patients with colorectal liver metastases treated with partial hepatectomy (n = 14) or cryosurgery (n = 10).

RESULTS

In both groups, IL-6 peak levels at the end of the operation were followed by peak levels at day 1 for HGF and CRP. SAA peak levels occurred on day 1 (hepatectomy group) and on day 4 (cryo group). The total HGF, IGF-I, and IL-6 responses were comparable in both groups. CRP and SAA responses were higher in the patients treated with cryosurgery than in patients after hepatectomy. Free IGF-I trough levels were lower in partial hepatectomy patients than in cryosurgery patients.

CONCLUSIONS

In patients with colorectal liver metastases the responses of the regenerating factors HGF, IGF-I, and IL-6 are comparable to those in patients treated with partial hepatectomy. Upregulation of acute phase protein production is higher in patients after cryosurgery than in patients after partial hepatectomy.

Interstitial laser thermotherapy in the treatment of colorectal liver metastases

Metastatic liver disease is the commonest cause of death in patients with colorectal cancer. A small proportion of these patients (10%) may be treated by surgical resection with five year survival approaching 35-40%. Alternative treatment modalities for localised hepatic disease include in situ ablative techniques that have the advantages of percutaneous application and minimal morbidity. These include Interstitial Laser Thermotherapy (ILT), Radio Frequency Ablation, Percutaneous Microwave therapy, and Focussed Ultrasound Therapy. This article focuses specifically on the development and utilisation of ILT in the treatment of colorectal liver metastases. It provides a review of the pathophysiological factors involved, present status of clinical studies, and future directions. ILT is a safe technique for the treatment of colorectal liver metastases. It may be delivered by minimally invasive techniques to lesions considered unresectable by present criteria. Limitations include the extent and completeness of tumour necrosis achieved as well as imaging techniques. Clinical problems include a lack of controlled studies. Assessment of long-term survival in prospective randomised trials is needed to assess the efficacy of this procedure.

Current treatment for colorectal cancer metastatic to the liver

Surgery is currently the only available treatment option which offers the potential for cure for patients with liver metastases from colorectal cancer. Of those who undergo a potentially curative operation for their primary tumour but subsequently recur, almost 80% will develop evidence of metastatic disease within the liver. Greater experience and improvements in technique in liver surgery, with an increasingly aggressive surgical approach to metastatic colorectal cancer to the liver, has resulted in prolonged disease-free survival with 5-year rates varying from 21% to 48%. In order to increase these numbers further and to treat patients not eligible for surgical therapy, new treatment modalities and strategies have been developed. This review presents an update of the current treatment for colorectal disease metastatic to the liver.

Differential regenerative response and expression of growth factors following hepatectomy of variable extent in rats

AIMS/BACKGROUND

Liver regeneration is a physiological mechanism which leads to restoration of the hepatic parenchyma following hepatectomy or toxic injury. This process is mediated by a wide variety of cytokines and growth factors. The aim of the present study was to evaluate the influence of hepatectomy extent on the levels of intrahepatic mRNAs for cell-cycle markers and growth factors in rats submitted to a 30%, two-third or 80% hepatectomy.

METHODS

Cyclins, thymidine kinase and growth factors mRNA levels were quantitatively assessed by RT-PCR at different time points post-hepatectomy (2h, 6h, 12h, days 1, 2, 6).

RESULTS

As compared with a two-third hepatectomy, cyclins and thymidine kinase mRNA levels were increased but with a delayed peak at day 2 in the 80% hepatectomy group and showed a progressive increase until day 6 in the 30% hepatectomy group; mRNA levels for HGF or TGFalpha were increased with a delayed peak at 12 h or day 2 in the 80% hepatectomy group, respectively and this delay was more pronounced in the 30% hepatectomy group with a peak at day 1 or day 6.

CONCLUSION

A regenerative response occurs whatever the extent of hepatectomy but the course of regeneration and expression of growth factors differs according to the volume of resected liver. A better knowledge of these events could improve the clinical results of hepatic resection for primary or metastatic liver disease.

Clinical relevance of transforming growth factor alpha, epidermal growth factor receptor, p53, and Ki67 in colorectal liver metastases and corresponding primary tumors

To determine whether the expression of transforming growth factor alpha (TGF-alpha), its receptor (epidermal growth factor receptor [EGFr]), p53 nuclear protein, and proliferation influences prognosis of patients with liver metastases, a study was performed in 45 liver metastases and 33 corresponding primary colorectal carcinomas in patients referred for liver surgery. The expression of TGF-alpha, EGFr, p53 nuclear protein, and proliferation rate was correlated with clinicopathological characteristics and survival after partial liver resection. In liver metastases, TGF-alpha expression was low in 42%, intermediate in 35%, and high in 23%. TGF-alpha expression was higher in liver metastases derived from lymph node-positive primary carcinomas, in synchronous and in irresectable liver metastases compared with those derived from lymph node-negative primary carcinomas, metachronous, and resectable liver metastases. Nuclear p53 expression was found in 83% of primary tumors and 71% of liver metastases. p53 expression did not correlate with the various clinicopathological characteristics. Ki67 expression was not associated with clinicopathological characteristics in primary and metastatic tumors. In the 38 patients in whom a partial liver resection was performed, median survival was 25 months in patients with a higher TGF-alpha expression in the metastasis than in the primary tumor and 60 months in patients with comparable or lower TGF-alpha expression in the metastasis than in the primary tumor (P = .036). Median survival after liver resection was 21 months in patients with p53-negative liver metastases and 58 months in patients with p53-positive metastases (P = .043). By multivariate analysis, p53 and EGFr expression on liver metastases were the best predictors of disease-free survival after partial liver resection, with relative risks of 2.38 and 3.33, respectively. In patients with colorectal liver metastases, referred for liver surgery, a higher TGF-alpha expression is associated with unfavorable tumor characteristics, whereas p53 and absence of EGFr expression is associated with a better survival after partial liver resection.