[Colorectal liver metastases. Neoadjuvant chemotherapy: aspects of medical and surgical oncology]

Intra-arterial EmboCept S® and DC Bead® effectively inhibit tumor growth of colorectal rat liver metastases

BACKGROUND

Intra-arterial therapy with embolics is established for the treatment of malignancies of the liver. However, there are no studies comparing the different effects of various embolics used in clinical practice. Herein, we analyzed the effect of 3 different embolics on tumor growth in a rat model of colorectal liver metastases.

METHODS

Eight days after subcapsular implantation of 5 × 105 colorectal cancer cells (CC531) in the left liver lobe of WAG/Rij rats were randomized into 4 groups (n = 8) and underwent intra-arterial hepatic therapy. Animals received either EmboCept S®, DC Bead® or Lipiodol® Ultra-Fluid. Animals of the control group received a comparable amount of saline. Tumor growth was measured on day 8 and 11 using a three-dimensional 40 MHz ultrasound device. On day 11 tumor and liver tissue were removed for histological and immunohistochemical analyses.

RESULTS

On day 11 animals of the control group showed a tumor growth of ~ 60% compared to day 8. Application of Lipiodol Ultra-Fluid® did not significantly influence tumor growth (~ 40%). In contrast, treatment with EmboCept S® or DC Bead® completely inhibited tumor growth. Of interest, application of EmboCept S® did not only completely inhibit tumor growth but even decreased tumor size. Immunohistochemical analysis showed a significant increase of necrotic areas within the tumors after application of EmboCept S® and DC Bead® compared to Lipiodol® Ultra-Fluid.

CONCLUSION

The present study demonstrates that an intra-arterial therapy with EmboCept S® and DC Bead®, but not Lipiodol® Ultra-Fluid, results in a complete inhibition of rat colorectal liver metastatic growth.

Therapeutic Strategies in Diseases of the Digestive Tract - 2015 and Beyond Targeted Therapies in Colon Cancer Today and Tomorrow

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer type in Western countries. Significant progress has been made in the last decade in the therapy of metastatic CRC (mCRC) with a median overall survival (OS) of patients exceeding 30 months. The integration of biologic targeted therapies and anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MABs) in the treatment of patients with genomically selected all-RAS wild-type mCRC leads to a significant progress in advanced incurable disease state. After the introduction of the anti-VEGF MAB bevacizumab, the FDA approved with ramucirumab the second antiangiogenic MAB for the mCRC treatment. Further new drugs are on the horizon and new diagnostic tools will be introduced soon.

KEY MESSAGES

Molecular heterogeneity of mCRC has been recognized as pivotal in the evolution of clonal populations during anti-EGFR therapies. Mutations in RAS genes predict a lack of response to anti-EGFR MABs. Mutations in the mitogen-activated protein kinase-phosphoinositide 3-kinase pathways like BRAF or PIK3CA mutations or HER2/ERBB2 or MET amplifications bypass EGFR signaling and also may confer resistance to anti-EGFR MABs. HER2/ERBB2 amplification is a further driver of resistance to anti-EGFR MABs in mCRC. The phase II study of HER2 Amplification for Colo-Rectal Cancer Enhanced Stratification (HERACLES) discovers that a dual HER2-targeted therapy may be an option for HER2-amplified mCRC. The mismatch repair deficiency predicts responsiveness to an immune checkpoint blockade with the anti-PD-1 immune checkpoint inhibitor pembrolizumab.

CONCLUSIONS

The understanding of primary (de novo) and secondary (acquired) resistance to anti-EGFR therapies, new targeted therapies, immuno-oncology and about predictive biomarkers in mCRC is guiding the development of rational therapeutic strategies. Combinations of targeted therapies are necessary to effectively treat drug-resistant cancers. Liquid biopsy is an upcoming new tool in the primary diagnosis and follow-up analysis of mutations in circulating tumor DNA.

Tumour growth of colorectal rat liver metastases is inhibited by hepatic arterial infusion of the mTOR-inhibitor temsirolimus after portal branch ligation

Portal branch ligation (PBL) can be performed before major hepatic resection of colorectal liver metastases (mCRC) to increase the remnant liver mass. However, PBL may also stimulate mCRC growth through hepatic arterial hyperperfusion and growth factor release. Herein, we studied whether hepatic arterial infusion (HAI) of the mTOR-inhibitor temsirolimus (Tem) is capable of inhibiting the growth of colorectal liver metastases after PBL. WAG/Rij rats were randomized to four groups (n=6 each) and underwent subcapsular implantation of 5×10(5) CC531 cells into the left liver lobe. The animals of two groups underwent simultaneous PBL of the tumour bearing liver lobe. Ten days later animals underwent a HAI either of temsirolimus (Tem and PBL Tem) or saline solution (Sham and PBL Sham). Tumour size was analyzed at days 10 and 13 using three-dimensional ultrasound. In Sham controls tumour volume increased by 43%. After PBL Sham tumour volume increased by 52%. In contrast, in animals undergoing HAI of temsirolimus the tumour growth was not only completely inhibited, but tumour volume was found decreased, irrespective of PBL. After HAI of temsirolimus immunohistochemistry revealed an increased cleaved caspase-3 activity, indicating stimulation of apoptotic cell death. In parallel temsirolimus treatment was associated with a significant reduction of PECAM-1 positive cells within the tumour tissue, implying a reduced tumour vascularisation. HAI of temsirolimus is capable of inhibiting the growth of CC531 colorectal rat liver metastases also after PBL.

Hepatic colorectal metastases involving infra-hepatic inferior vena cava in high risk patients for extended resection: an alternative method for achieving radical resection in patient with borderline liver remnant

Resection is the only chance of cure for isolated liver metastases from colorectal cancer. In the case of extended parenchymal resections, one crucial point is the ischemic damage to the remnant liver. We report an alternative technique for extremely extended liver resections without total hilar clamping for borderline liver remnants. Two patients presented with invasion of the infrahepatic vena cava, both with an estimated live remnant ≤20 %. The crucial point of the technique is the absence of a portal triad clamping in under beating heart-extracorporeal circulation. In both patients resection margins were free of disease. No signs of liver insufficiency were noted. Survival was more than 2 years in both cases. We believe that aggressive treatment of liver colorectal metastases should be given to all suitable patients. This operation may be added to the techniques that can be offered to these patients.

Hepatic arterial infusion but not systemic application of cetuximab in combination with oxaliplatin significantly reduces growth of CC531 colorectal rat liver metastases

PURPOSE

Systemic chemotherapy still represents the gold standard in the treatment of irresectable colorectal liver metastases. Modern anticancer agents like the monoclonal antibody cetuximab have improved the outcome of patients in clinical studies. As hepatic arterial infusion (HAI) is capable to potentially increase the anticancer effect of cytostatics, we herein studied whether HAI of cetuximab (CE) as a single agent or in combination with oxaliplatin (OX) exerts increased anticancer effects compared to the systemic application (SYS) of the drugs.

METHODS

WAG/Rij rats were randomized to eight groups and underwent 10 days after subcapsular hepatic tumor implantation either HAI or SYS of CE, OX, or the combination of both agents (CE + OX). Saline-treated animals served as controls. Tumor volume was measured at days 10 and 13 using three-dimensional ultrasound. On day 13, liver and tumor tissue was sampled for histological and immunohistochemical analysis.

RESULTS

In controls, the tumor volume significantly increased from day 10 to 13. Application of OX alone via HAI or SYS did not inhibit tumor growth compared to controls. SYS of CE or CE + OX did also not reduce tumor growth. In contrast, HAI of CE and CE + OX significantly inhibited tumor growth. HAI of CE significantly reduced tumor vascularization as measured by the number of platelet endothelial cell adhesion molecule-1-positive cells and significantly increased the number of apoptotic tumor cells as measured by the cellular caspase-3 expression.

CONCLUSION

HAI of CE and CE + OX reduces tumor growth of colorectal rat liver metastases involving the inhibition of angiogenesis and induction of tumor cell apoptosis.

Liver-directed chemotherapy of cetuximab and bevacizumab in combination with oxaliplatin is more effective to inhibit tumor growth of CC531 colorectal rat liver metastases than systemic chemotherapy

Colorectal carcinoma is, through to its high rate of liver metastasis (mCRC), the second most cause of cancer death worldwide. Tumor resection represents the only potential cure. In cases of unresectable disease systemic chemotherapy (sCHT) remains the therapy of choice. Modern sCHT regimens including biological agents can induce tumor response that leads to curative surgery of initially unresectable mCRC. However, liver-directed therapy via hepatic arterial infusion (HAI) may produce higher response rates than sCHT. Herein we studied whether a HAI of cetuximab (CE) plus bevacizumab (BE) with or without oxaliplatin (OX) can inhibit tumor growth in a rat model. WAG/Rij rats underwent subcapsular hepatic tumor implantation. After 10 days animals received either HAI or sCHT of CE plus BE, OX or all three drugs. Saline-treated animals served as controls. Tumor growth was estimated at day 10 and 13. On day 13 liver and tumor tissue was studied histologically and immunohistochemically. In controls the tumors grew about 50 %. OX alone was not capable of inhibiting tumor growth. In contrast, CE plus BE given as HAI significantly reduced tumor growth compared to sCHT (p < 0.05). HAI of CE plus BE combined with OX yielded an even more pronounced inhibition of tumor growth. Immunohistochemistry revealed a decreased tumor cell proliferation and tumor vascularization. The present study demonstrates that HAI of CE plus BE is effective to inhibit tumor growth. This effect is even more pronounced in combination with OX. Systemic application of these agents cannot achieve comparable effects.

Treatment results of FOLFOX chemotherapy before surgery for lymph node metastasis of advanced colorectal cancer with synchronous liver metastasis: the status of LN metastasis and vessel invasions at the primary site in patients who responded to FOLFOX

PURPOSE

The combination of chemotherapy and surgery holds promise for improving CRC patient prognosis. We evaluated the pathological impact of chemotherapy on primary lesions and lymph node (LN) metastases retrospectively.

METHODS

Sixteen CRC patients with synchronous liver metastasis underwent a radical operation between March 2005 and August 2007. Eight of the 16 cases (surgery group) were operated on for the primary lesion without chemotherapy and another 8 cases (chemotherapy group) were operated on after chemotherapy with FOLFOX (median: 8 courses).

RESULTS

Five of the 8 patients in the surgery group were found to have pathological LN metastasis (62.5%; N0 37.5%, N1 37.5%, N2 25%). However, only 2 of the 8 patients in the chemotherapy group were found to have LN metastasis (25%; N0 75%, N1 25%, N2 0%). The ratio of LN metastasis (number of metastatic LNs/resected LNs in total) was 11.1% in the surgery group, but it was 4.8% in the chemotherapy group. Necrotic areas were widely detected in the LN specimens of the chemotherapy group. The percentage of lymphatic (ly) and vascular (v) invasion in the primary lesions was smaller in the chemotherapy group (ly 12.5% vs. 25.0%) than in the surgery group (ly 62.5% vs. 50.0%). The patients in the chemotherapy group had no significant adverse effects and did not show an worse survival rate overall than the surgery group.

CONCLUSIONS

A promising effect of chemotherapy on the status of LN metastasis and vessel invasions at the primary site was observed in the patients who responded to FOLFOX.

[Systemic treatment of advanced colorectal cancer]

The introduction of modern chemotherapeutic drugs and targeted therapies has substantially changed the treatment of advanced colorectal cancer (aCRC). Thus, median survival of stage IV patients was increased from 6 months under best supportive care to over 2 years if all drugs are administered. Also, new combination therapies may cause irresectable liver metastases to shrink to such an extent that they may be resected (downsizing). Patients who were formerly treated with palliative intent may now be cured. However, not all patients benefit from the new compounds. Very recently, new genetic characteristics were identified as potential molecular biomarkers that may predict response to anti-EGFR therapy, a specific targeted therapy; the marker detected is the mutational status of the oncogene k-ras. Only patients with wild-type k-ras-expressing tumors respond to anti-EGFR antibodies. The integration of biomarker analysis into the clinical routine represents an important step toward customized treatment of cancer patients.