The impact of liver resection on the dihydrouracil:uracil plasma ratio in patients with colorectal liver metastases.

PURPOSE: The dihydrouracil (DHU):uracil (U) plasma ratio is a promising marker for identification of dihydropyrimidine dehydrogenase (DPD)-deficient patients. The objective of this study was to determine the effect of liver resection on the DHU:U plasma ratio in patients with colorectal liver metastases (CRLM). METHODS: An observational study was performed in which DHU:U plasma ratios in patients with CRLM were analyzed prior to and 1 day after liver resection. In addition, the DHU:U plasma ratio was quantified in six additional patients 4-8 weeks after liver resection to explore long-term effects on the DHU:U plasma ratio. Quantification of U and DHU plasma levels was performed using a validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay. RESULTS: The median (range) DHU:U plasma ratio in 15 patients prior to liver resection was 10.7 (2.6-14.4) and was significantly reduced to 5.5 (< quantification limit (LLOQ-10.5) 1 day after resection (p = 0.0026). This reduction was caused by a decrease in DHU plasma levels from 112.0 (79.8-153) ng/mL to 41.2 (< LLOQ-160) ng/mL 1 day after resection (p = 0.0004). Recovery of the DHU:U plasma ratio occurred 4-8 weeks after liver resection, which was shown by a median (range) DHU:U plasma ratio in six patients of 9.1 (6.9-14.5). CONCLUSION: Liver resection leads to very low DHU:U plasma ratios 1 day after liver resection, which is possibly caused by a reduction in DPD activity. Quantification of the DHU:U plasma ratios directly after liver resection could lead to false-positive identification of DPD deficiency and is therefore not advised.

Multipolar radiofrequency ablation for colorectal liver metastases close to major hepatic vessels.

BACKGROUND: Resection of colorectal liver metastases (CRLM) is often hindered by their location close to the major hepatic vessels. So far, radiofrequency ablation for perivascular tumours was thought to be ineffective and unsafe due to either the heat sink effect or vascular thrombosis. The aim of this study was to examine whether RFA using multipolar probes could be a safe and effective option for CRLM adjacent to major hepatic vessels. METHODS: Patients were treated with multipolar RFA during an open procedure using 3 simultaneously placed electrodes. In 52 consecutive patients with CRLM, 144 tumours were ablated with RFA. In 16 out of 52 (31%) patients, metastases were abutting major hepatic vessels. We examined whether perivascular location was a risk factor for local tumour progression. The relation between perivascular location and time to local tumour progression and recurrence free survival was assessed using cox-regression analysis. RESULTS: All patients were followed for at least 3 years after RFA unless they deceased before this time. Local tumour progression following RFA occurred in 17 out of 144 tumours (12%), of which 4 out of 21 were perivascular tumours. Tumour size was the only risk factor for local tumour progression in this study. Proximity to large vessels was neither a risk factor for local local tumour progression, nor for time to local tumour progression or recurrence free survival. DISCUSSION: This study indicates that patients with CRLM abutting any of the large hepatic vessels can be safe and effectively treated with RFA when using a multipolar system.

Viable tumor tissue adherent to needle applicators after local ablation: a risk factor for local tumor progression.

BACKGROUND: Local tumor progression (LTP) is a serious complication after local ablation of malignant liver tumors, negatively influencing patient survival. LTP may be the result of incomplete ablation of the treated tumor. In this study, we determined whether viable tumor cells attached to the needle applicator after ablation was associated with LTP and disease-free survival. METHODS: In this prospective study, tissue was collected of 96 consecutive patients who underwent local liver ablations for 130 liver malignancies. Cells and tissue attached to the needle applicators were analyzed for viability using glucose-6-phosphate-dehydrogenase staining and autofluorescence intensity levels of H&E stained sections. Patients were followed-up until disease progression. RESULTS: Viable tumor cells were found on the needle applicators after local ablation in 26.7% of patients. The type of needle applicator used, an open approach, and the omission of track ablation were significantly correlated with viable tumor tissue adherent to the needle applicator. The presence of viable cells was an independent predictor of LTP. The attachment of viable cells to the needle applicators was associated with a shorter time to LTP. CONCLUSIONS: Viable tumor cells adherent to the needle applicators were found after ablation of 26.7% of patients. An independent risk factor for viable cells adherent to the needle applicators is the omission of track ablation. We recommend using only RFA devices that have track ablation functionality. Adherence of viable tumor cells to the needle applicator after local ablation was an independent risk factor for LTP.

A randomized two arm phase III study in patients post radical resection of liver metastases of colorectal cancer to investigate bevacizumab in combination with capecitabine plus oxaliplatin (CAPOX) vs CAPOX alone as adjuvant treatment.

BACKGROUND: About 50% of patients with colorectal cancer are destined to develop hepatic metastases. Radical resection is the most effective treatment for patients with colorectal liver metastases offering five year survival rates between 36-60%. Unfortunately only 20% of patients are resectable at time of presentation. Radiofrequency ablation is an alternative treatment option for irresectable colorectal liver metastases with reported 5 year survival rates of 18-30%. Most patients will develop local or distant recurrences after surgery, possibly due to the outgrowth of micrometastases present at the time of liver surgery. This study aims to achieve an improved disease free survival for patients after resection or resection combined with RFA of colorectal liver metastases by adding the angiogenesis inhibitor bevacizumab to an adjuvant regimen of CAPOX. METHODS/DESIGN: The Hepatica study is a two-arm, multicenter, randomized, comparative efficacy and safety study. Patients are assessed no more than 8 weeks before surgery with CEA measurement and CT scanning of the chest and abdomen. Patients will be randomized after resection or resection combined with RFA to receive CAPOX and Bevacizumab or CAPOX alone. Adjuvant treatment will be initiated between 4 and 8 weeks after metastasectomy or resection in combination with RFA. In both arms patients will be assessed for recurrence/new occurrence of colorectal cancer by chest CT, abdominal CT and CEA measurement. Patients will be assessed after surgery but before randomization, thereafter every three months after surgery in the first two years and every 6 months until 5 years after surgery. In case of a confirmed recurrence/appearance of new colorectal cancer, patients can be treated with surgery or any subsequent line of chemotherapy and will be followed for survival until the end of study follow up period as well. The primary endpoint is disease free survival. Secondary endpoints are overall survival, safety and quality of life. CONCLUSION: The HEPATICA study is designed to demonstrate a disease free survival benefit by adding bevacizumab to an adjuvant regime of CAPOX in patients with colorectal liver metastases undergoing a radical resection or resection in combination with RFA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00394992.

Assessment of viable tumour tissue attached to needle applicators after local ablation of liver tumours.

AIM: Local recurrence and needle track seeding are serious complications after local ablation for liver malignancies and potentially affect long-term survival. The aim of this study was to assess the incidence of viable tissue adherent to the needle applicators after ablation to gain insight into the possible mechanisms of local recurrence and needle track seeding. METHODS: A total of 40 consecutive patients underwent 59 local liver ablations. Cells and tissue attached to the needle applicators were analysed for morphology (HE, PAP and Giemsa staining) and viability (G6PD staining). RESULTS: Macroscopic tissue adherence was visible following 31 of the ablative procedures, all with radiofrequency ablation. Four applications were performed percutaneously and 27 during an open procedure. Morphologically intact tumour cells could be identified in 8 patients (20%), and viable tumour cells in 5 patients (12.5%). Morphologically intact tumour cells or viable tumour cells could only be demonstrated when track ablation was not performed. CONCLUSION: Viable tumour cells adherent to the needle applicators were found in an alarming 12.5% of patients after local ablation. We recommend track ablation not only after the procedure but also during any shifting and (re-)positioning to prevent shedding of viable tumour cells during or after ablation.

Randomized Phase III Study to Assess Efficacy and Safety of Adjuvant CAPOX with or without Bevacizumab in Patients after Resection of Colorectal Liver Metastases: HEPATICA study.

Bevacizumab is a humanized monoclonal antibody targeting vascular endothelial growth factor (VEGF). Recurrence after resection of colorectal liver metastases (CRLMs), presumably caused by VEGF-mediated outgrowth of micrometastases, might decrease when VEGF is inhibited. This study examines the efficacy and safety of adding bevacizumab to an adjuvant regimen of CAPOX in patients undergoing radical resection for their CRLMs. Patients with resected CRLMs were randomized after surgery to receive CAPOX and bevacizumab (arm A) or CAPOX alone (arm B) as adjuvant treatment. CAPOX was given in both arms for a total of eight cycles. Bevacizumab was administered for 16 cycles. The primary end point was disease-free survival (DFS). Secondary outcomes were overall survival (OS), toxicity, and quality of life (QoL). In total, 79 patients were randomized. At the time of analysis, 23 events were encountered in arm A and 20 in arm B. One-year DFS rate was 79% [95% confidence interval (CI): 68%-93%] and 68% (95% CI: 55%-85%) for arm A and B, respectively (P=.89). Toxicity was evaluated for 75 patients. No significant differences in toxicity between the two arms were found. QoL scores were higher in arm A, of which emotional functioning and global QoL scores were significant. Adding bevacizumab to a CAPOX regimen in patients undergoing a resection for their CLM is safe and showed higher QoL scores compared with CAPOX alone. Because of premature closure of the study, conclusions about the effect on DFS of additional VEGF inhibition in this setting could not yet be made.

A Validated Prognostic Multigene Expression Assay for Overall Survival in Resected Colorectal Cancer Liver Metastases.

PURPOSE: Risk stratification after surgery for colorectal cancer liver metastases (CRLM) is achieved using clinicopathologic variables, however, is of limited accuracy. We sought to derive and externally validate a multigene expression assay prognostic of overall survival (OS) that is superior to clinicopathologic variables in patients with surgically resected CRLM. EXPERIMENTAL DESIGN: We measured mRNA expression in prospectively collected frozen tumor from 96 patients with surgically resected CRLM at Memorial Sloan Kettering Cancer Center (MSKCC, New York, NY). We retrospectively generated a 20-gene molecular risk score (MRS) and compared its prognostic utility for OS and recurrence-free survival (RFS) with three common clinical risk scores (CRS). We then tested the prognostic ability of the MRS in an external validation cohort (European) of 119 patients with surgically resected CRLM at the University Medical Center Utrecht (Utrecht, the Netherlands) and Paul Brousse Hospital (Villejuif, France). RESULTS: For OS in the MSKCC cohort, MRS was the strongest independent prognosticator (HR, 3.7-4.9; P < 0.001) followed by adjuvant chemotherapy (HR, 0.3; P ≤ 0.001). For OS in the European cohort, MRS was the only independent prognosticator (HR, 3.5; P = 0.007). For RFS, MRS was also independently prognostic in the MSKCC cohort (HR, 2.4-2.6; P ≤ 0.001) and the European cohort (HR, 1.6-2.5; P ≤ 0.05). CONCLUSIONS: Compared with CRSs, the MRS is more accurate, broadly applicable, and an independent prognostic biomarker of OS in resected CRLM. This MRS is the first externally validated prognostic multigene expression assay after metastasectomy for CRLM and warrants prospective validation. Clin Cancer Res; 22(10); 2575-82. ©2016 AACR.

SIRT1/PGC1α-Dependent Increase in Oxidative Phosphorylation Supports Chemotherapy Resistance of Colon Cancer.

PURPOSE: Chemotherapy treatment of metastatic colon cancer ultimately fails due to development of drug resistance. Identification of chemotherapy-induced changes in tumor biology may provide insight into drug resistance mechanisms. EXPERIMENTAL DESIGN: We studied gene expression differences between groups of liver metastases that were exposed to preoperative chemotherapy or not. Multiple patient-derived colonosphere cultures were used to assess how chemotherapy alters energy metabolism by measuring mitochondrial biomass, oxygen consumption, and lactate production. Genetically manipulated colonosphere-initiated tumors were used to assess how altered energy metabolism affects chemotherapy efficacy. RESULTS: Gene ontology and pathway enrichment analysis revealed significant upregulation of genes involved in oxidative phosphorylation (OXPHOS) and mitochondrial biogenesis in metastases that were exposed to chemotherapy. This suggested chemotherapy induces a shift in tumor metabolism from glycolysis towards OXPHOS. Indeed, chemotreatment of patient-derived colonosphere cultures resulted in an increase of mitochondrial biomass, increased expression of respiratory chain enzymes, and higher rates of oxygen consumption. This was mediated by the histone deacetylase sirtuin-1 (SIRT1) and its substrate, the transcriptional coactivator PGC1α. Knockdown of SIRT1 or PGC1α prevented chemotherapy-induced OXPHOS and significantly sensitized patient-derived colonospheres as well as tumor xenografts to chemotherapy. CONCLUSIONS: Chemotherapy of colorectal tumors induces a SIRT1/PGC1α-dependent increase in OXPHOS that promotes tumor survival during treatment. This phenomenon is also observed in chemotherapy-exposed resected liver metastases, strongly suggesting that chemotherapy induces long-lasting changes in tumor metabolism that potentially interfere with drug efficacy. In conclusion, we propose a novel mechanism of chemotherapy resistance that may be clinically relevant and therapeutically exploitable.

PDGFRB promotes liver metastasis formation of mesenchymal-like colorectal tumor cells.

In epithelial tumors, the platelet-derived growth factor receptor B (PDGFRB) is mainly expressed by stromal cells of mesenchymal origin. Tumor cells may also acquire PDGFRB expression following epithelial-to-mesenchymal transition (EMT), which occurs during metastasis formation. Little is known about PDGFRB signaling in colorectal tumor cells. We studied the relationship between PDGFRB expression, EMT, and metastasis in human colorectal cancer (CRC) cohorts by analysis of gene expression profiles. PDGFRB expression in primary CRC was correlated with short disease-free and overall survival. PDGFRB was co-expressed with genes involved in platelet activation, transforming growth factor beta (TGFB) signaling, and EMT in three CRC cohorts. PDGFRB was expressed in mesenchymal-like tumor cell lines in vitro and stimulated invasion and liver metastasis formation in mice. Platelets, a major source of PDGF, preferentially bound to tumor cells in a non-activated state. Platelet activation caused robust PDGFRB tyrosine phosphorylation on tumor cells in vitro and in liver sinusoids in vivo. Platelets also release TGFB, which is a potent inducer of EMT. Inhibition of TGFB signaling in tumor cells caused partial reversion of the mesenchymal phenotype and strongly reduced PDGFRB expression and PDGF-stimulated tumor cell invasion. These results suggest that PDGFRB may contribute to the aggressive phenotype of colorectal tumors with mesenchymal properties, most likely downstream of platelet activation and TGFB signaling.

Exploring gene expression signatures for predicting disease free survival after resection of colorectal cancer liver metastases.

BACKGROUND AND OBJECTIVES: This study was designed to identify and validate gene signatures that can predict disease free survival (DFS) in patients undergoing a radical resection for their colorectal liver metastases (CRLM). METHODS: Tumor gene expression profiles were collected from 119 patients undergoing surgery for their CRLM in the Paul Brousse Hospital (France) and the University Medical Center Utrecht (The Netherlands). Patients were divided into high and low risk groups. A randomly selected training set was used to find predictive gene signatures. The ability of these gene signatures to predict DFS was tested in an independent validation set comprising the remaining patients. Furthermore, 5 known clinical risk scores were tested in our complete patient cohort. RESULT: No gene signature was found that significantly predicted DFS in the validation set. In contrast, three out of five clinical risk scores were able to predict DFS in our patient cohort. CONCLUSIONS: No gene signature was found that could predict DFS in patients undergoing CRLM resection. Three out of five clinical risk scores were able to predict DFS in our patient cohort. These results emphasize the need for validating risk scores in independent patient groups and suggest improved designs for future studies.

Circulating CD95-ligand as a potential prognostic marker for recurrence in patients with synchronous colorectal liver metastases.

AIM: To assess whether circulating soluble CD95 ligand (sCD95L) levels are associated with recurrence-free survival (RFS) in patients with synchronous colorectal liver metastases. PATIENTS AND METHODS: Blood samples were obtained from 62 patients with synchronous colorectal liver metastases before and after liver surgery. Serum sCD95L levels were determined using enzyme-linked immunosorbent assay (ELISA). Cox regression analysis was performed to determine the correlation between sCD95L levels and RFS and overall survival (OS). RESULTS: Median follow-up was 33 months. High pre-operative sCD95L levels were associated with poor RFS and OS in univariable (p=0.019 and p=0.020) and multivariable analyses (p=0.020 and p=0.003). CONCLUSION: Preoperatives CD95L is a potential prognostic factor for RFS and OS of patients undergoing surgery for synchronous colorectal liver metastases. Low preoperatives CD95L levels may help identify a subgroup of patients with synchronous liver metastases that are likely to benefit from liver surgery.

Liver surgery induces an immediate mobilization of progenitor cells in liver cancer patients: A potential role for G-CSF.

BACKGROUND: In preclinical models recruitment of bone-marrow derived (endothelial) progenitor cells (BD(E)PCs) contributes to tumor growth and metastasis formation. Here we investigated whether these (E)PCs and mobilizing cytokines are released after partial hepatectomy or radiofrequency ablation (RFA) for liver tumors. In addition, we tested whether G-CSF could play a role in EPC mobilization in mice and in human volunteers. RESULTS: Patients undergoing partial hepatectomy or RFA showed an instantaneous release of EPCs following laparotomy and mobilization of the liver. Elevated EPC levels were maintained during the entire procedure, but dropped to near-baseline levels 4 h after completion of the procedure. Plasma G-CSF levels showed a 5-10-fold increase after the procedure and low-dose G-CSF administration to mice or healthy volunteers was sufficient to induce an immediate release of EPCs. Surgery also caused an increase in the plasma levels of VEGF, but not SDF-1alpha. METHODS: Before, during and after liver surgery plasma and mononuclear cells were collected from 12 patients undergoing partial hepatectomy or RFA. To explore the role of G-CSF C57Bl/6 mice and 20 human volunteers received G-CSF (0.3, 3 or 300microg). In all individuals, (E)PC numbers were determined by flow cytometry at predefined timepoints shortly after therapy. Plasma levels of G-CSF, VEGF and SDF-1alpha were measured by ELISA. CONCLUSION: Compliant with previous published data concerning VDA and chemotherapy treatment, liver surgery induces an instantaneous release of EPCs, conceivably in response to elevated G-CSF levels. This suggests the value of exploring therapeutic avenues to prevent this process.