Eve Simoneau

Vessel co-option mediates resistance to anti-angiogenic therapy in liver metastases

The efficacy of angiogenesis inhibitors in cancer is limited by resistance mechanisms that are poorly understood. Notably, instead of through the induction of angiogenesis, tumor vascularization can occur through the nonangiogenic mechanism of vessel co-option. Here we show that vessel co-option is associated with a poor response to the anti-angiogenic agent bevacizumab in patients with colorectal cancer liver metastases. Moreover, we find that vessel co-option is also prevalent in human breast cancer liver metastases, a setting in which results with anti-angiogenic therapy have been disappointing. In preclinical mechanistic studies, we found that cancer cell motility mediated by the actin-related protein 2/3 complex (Arp2/3) is required for vessel co-option in liver metastases in vivo and that, in this setting, combined inhibition of angiogenesis and vessel co-option is more effective than the inhibition of angiogenesis alone. Vessel co-option is therefore a clinically relevant mechanism of resistance to anti-angiogenic therapy and combined inhibition of angiogenesis and vessel co-option might be a warranted therapeutic strategy.

Portal vein embolization stimulates tumour growth in patients with colorectal cancer liver metastases

OBJECTIVES Portal vein embolization (PVE) can facilitate the resection of previously unresectable colorectal cancer (CRC) liver metastases. Bevacizumab is being used increasingly in the treatment of metastatic CRC, although data regarding its effect on post-embolization liver regeneration and tumour growth are conflicting. The objective of this observational study was to assess the impact of pre-embolization bevacizumab on liver hypertrophy and tumour growth. METHODS Computed tomography scans before and 4 weeks after PVE were evaluated in patients who received perioperative chemotherapy with or without bevacizumab. Scans were compared with scans obtained in a control group in which no PVE was administered. Future liver remnant (FLR), total liver volume (TLV) and total tumour volume (TTV) were measured. Bevacizumab was discontinued ≥ 4 weeks before PVE. RESULTS A total of 109 patients and 11 control patients were included. Portal vein embolization induced a significant increase in TTV: the right lobe increased by 33.4% in PVE subjects but decreased by 34.8% in control subjects (P < 0.001), and the left lobe increased by 49.9% in PVE subjects and decreased by 33.2% in controls (P= 0.022). A total of 52.8% of the study group received bevacizumab and 47.2% did not. There was no statistical difference between the two chemotherapy groups in terms of tumour growth. Median FLR after PVE was similar in both groups (28.8% vs. 28.7%; P= 0.825). CONCLUSIONS Adequate liver regeneration was achieved in patients who underwent PVE. However, significant tumour progression was also observed post-embolization.

Predictors of response to radio‐embolization (TheraSphere®) treatment of neuroendocrine liver metastasis

BACKGROUND Neuroendocrine tumours (NET) frequently metastasize to the liver. NET liver metastasis has been shown to respond to Yttrium-90 microspheres therapy. The aims of the present study were to define factors that predict the response to radio-embolization in patients with NET liver metastases. METHODS From January 2006 until March 2009, all patients with NET liver metastasis that received radio-embolization using TheraSphere® (glass microspheres) were reviewed. The response was determined by a change in the percentage of necrosis (ΔN%) after the first radio-embolization based on the modified RECIST criteria (mRECIST) criteria. The following confounding variables were measured: age, gender, size of the lesions, liver involvement, World Health Organization (WHO) classification, the presence of extra-hepatic metastasis, octereotide treatment and previous operative [surgery and (RFA)] and non-operative treatments (chemo-embolization and bland-embolization). RESULTS In all, 25 patients were identified, with a median follow-up of 21.7 months. The median age was 64.6 years, 28% had extra-hepatic metastasis and 56% were WHO stage 2. Post-treatment, the mean ΔN% was 48.4%. Previous surgical therapy was a significant predictor of the response with a response rate of 66.7 ΔN% vs. 31.5 ΔN% (P= 0.02). Bilateral liver disease, a high percentage of liver involvement and large metastatic lesions were inversely related to the degree of tumour response although did not reach statistical significance. CONCLUSION Radio-embolization increased the necrosis of NET liver metastasis mainly in patients with less bulky disease. This may imply that surgical therapy before radio-embolization would increase the response rates.

Portal vein embolization and its effect on tumour progression for colorectal cancer liver metastases

The aim of this study was to evaluate the long‐term outcomes of patients with colorectal cancer liver metastasis (CRCLM) exhibiting disease progression after portal vein embolization (PVE).

Staged hepatectomy for bilobar colorectal hepatic metastases

OBJECTIVES This study describes the management of patients with bilobar colorectal liver metastases (CRLM). METHODS A retrospective collection of data on all patients with CRLM who were considered for staged resection (n= 85) from January 2003 to January 2011 was performed. Patients who underwent one hepatic resection were considered to have had a failed staged resection (FSR), whereas those who underwent a second or third hepatic resection to produce a cure were considered to have had a successful staged resection (SSR). Survival was calculated from the date of diagnosis of liver metastases. Complete follow-up and dates of death were obtained from the Government of Quebec population database. RESULTS Median survival was 46 months (range: 30-62 months) in the SSR group and 22 months (range: 19-29 months) in the FSR group. Rates of 5-year survival were 42% and 4% in the SSR and FSR groups, respectively. Fifteen of the 19 patients who remained alive at the last follow-up date belonged to the SSR group. CONCLUSIONS In patients in whom staged resection for bilobar CRLM is feasible, surgery would appear to offer benefit.

Preoperative selection of patients with colorectal cancer liver metastasis for hepatic resection

Surgical resection of colorectal liver metastases (CRLM) has a well-documented improvement in survival. To benefit from this intervention, proper selection of patients who would be adequate surgical candidates becomes vital. A combination of imaging techniques may be utilized in the detection of the lesions. The criteria for resection are continuously evolving; currently, the requirements that need be met to undergo resection of CRLM are: the anticipation of attaining a negative margin (R0 resection), whilst maintaining an adequate functioning future liver remnant. The timing of hepatectomy in regards to resection of the primary remains controversial; before, after, or simultaneously. This depends mainly on the tumor burden and symptoms from the primary tumor. The role of chemotherapy differs according to the resectability of the liver lesion(s); no evidence of improved survival was shown in patients with resectable disease who received preoperative chemotherapy. Presence of extrahepatic disease in itself is no longer considered a reason to preclude patients from resection of their CRLM, providing limited extra-hepatic disease, although this currently is an area of active investigations. In conclusion, we review the indications, the adequate selection of patients and perioperative factors to be considered for resection of colorectal liver metastasis.

Neoadjuvant chemotherapy does not impair liver regeneration following hepatectomy or portal vein embolization for colorectal cancer liver metastases.

Treatment strategies for colorectal cancer liver metastasis (CRCLM) such as major hepatectomy and portal vein embolization (PVE) rely on liver regeneration. We aim to investigate the effect of neoadjuvant chemotherapy on liver regeneration occurring after PVE and after major hepatectomy.

Unresectable pancreatic adenocarcinoma: do we know who survives?

BACKGROUND This study attempts to define clinical predictors of survival in patients with unresectable pancreatic adenocarcinoma (UPA). METHODS A retrospective study of 94 consecutive patients diagnosed with UPA from 2001 to 2006 was performed. Using data for these patients, a symptom score was devised through a forward stepwise Cox proportional hazards model based on four weighted criteria: weight loss of >10% of body weight; pain; jaundice, and smoking. The symptom score was subsequently validated in a distinct cohort of 32 patients diagnosed with UPA in 2007. RESULTS In the original cohort, the overall median survival was 9.0 months (95% confidence interval [CI] 7.6-10.4). This altered to 10.3 months (95% CI 6.1-14.5) in patients with locally advanced disease, and 6.6 months (95% CI 4.2-9.0) in patients with distant metastasis. Median survival was 14.6 months (95% CI 13.1-16.1) in patients with a low symptom (LS) score and 6.3 months (95% CI 4.1-8.5) in patients with a high symptom (HS) score. A total of 73% of LS score patients survived beyond 9 months, compared with only 38% of HS score patients (P<0.001). The discrimination of the LS score was greater than that of any conventional method, including imaging. The validation cohort confirmed the discriminative ability of the symptom score for survival. CONCLUSIONS A simple and clinically meaningful point-based symptom score can successfully predict survival in patients with UPA.

International consensus guidelines for scoring the histopathological growth patterns of liver metastasis

Background:Liver metastases present with distinct histopathological growth patterns (HGPs), including the desmoplastic, pushing and replacement HGPs and two rarer HGPs. The HGPs are defined owing to the distinct interface between the cancer cells and the adjacent normal liver parenchyma that is present in each pattern and can be scored from standard haematoxylin-and-eosin-stained (H&E) tissue sections. The current study provides consensus guidelines for scoring these HGPs.Methods:Guidelines for defining the HGPs were established by a large international team. To assess the validity of these guidelines, 12 independent observers scored a set of 159 liver metastases and interobserver variability was measured. In an independent cohort of 374 patients with colorectal liver metastases (CRCLM), the impact of HGPs on overall survival after hepatectomy was determined.Results:Good-to-excellent correlations (intraclass correlation coefficient >0.5) with the gold standard were obtained for the assessment of the replacement HGP and desmoplastic HGP. Overall survival was significantly superior in the desmoplastic HGP subgroup compared with the replacement or pushing HGP subgroup (P=0.006).Conclusions:The current guidelines allow for reproducible determination of liver metastasis HGPs. As HGPs impact overall survival after surgery for CRCLM, they may serve as a novel biomarker for individualised therapies.

Portal vein embolization effect on colorectal cancer liver metastasis progression: Lessons learned

Colorectal liver metastasis (CRLM) is the major cause of death in patients diagnosed with colorectal cancer. The gold standard treatment of CRLM is surgical resection. Yet, in the past, more than half of these patients were deemed unresectable due to the inadequate future liver remnant (FLR). The introduction of efficient portal vein embolization (PVE) preoperatively allowed more resections of metastasis in CRLM patients by stimulating adequate liver hypertrophy. However, several experimental and clinical studies reported tumor progression after PVE which critically influences the subsequent management of these patients. The underlying pathophysiological mechanism of tumor progression post-PVE is still not fully understood. In spite of the adverse effects of PVE, it remains a potentially curative procedure in patients who would remain otherwise unresectable because of the insufficient FLR. Currently, the challenge is to halt tumor proliferation following PVE in patients who require this technique. This could potentially be achieved by either attempting to suppress the underlying oncologic stimulus or by inhibiting tumor growth once observed after PVE, without jeopardizing liver regeneration. More research is still required to better identify patients at risk of experiencing tumor growth post-PVE.