Liver-directed therapies in metastatic colorectal cancer

Colorectal cancer (CRC) is a major health concern in the United States (US) with over 140,000 new cases diagnosed in 2012. The most common site for CRC metastases is the liver. Hepatic resection is the treatment of choice for colorectal liver metastases (CLM), with a 5-year survival rate ranging from 35% to 58%. Unfortunately, only about 20% of patients are eligible for resection. There are a number of options for extending resection to more advanced patients including systemic chemotherapy, portal vein embolization (PVE), two stage hepatectomy, ablation and hepatic artery infusion (HAI). There are few phase III trials comparing these treatment modalities, and choosing the right treatment is patient dependent. Treating hepatic metastases requires a multidisciplinary approach and knowledge of all treatment options as there continues to be advances in management of CLM. If a patient can undergo a treatment modality in order to increase their potential for future resection this should be the primary goal. If the patient is still deemed unresectable then treatments that lengthen disease-free and overall-survival should be pursued. These include chemotherapy, ablation, HAI, chemoembolization, radioembolization (RE) and stereotactic radiotherapy.     

Integrating anti-EGFR therapies in metastatic colorectal cancer

Colorectal cancer remains one of the most common causes of cancer diagnoses and mortality in the United States. The treatment of metastatic colorectal cancer has evolved significantly over the last decade with near-tripling of patient survival rate. A significant contribution to this outcome was the advent of novel targeted agents, such as the epidermal growth factor (EGFR) inhibitors. In an era of emphasis on refining therapy, the presence of KRAS mutation will predict for resistance and limit exposure to patients who are more likely to benefit. In contrast, the presence of BRAF mutations does not seem to have a predictive value. Agents that are thought to reverse resistance to EGFR inhibitors such as those targeting PI3K, c-MET or IGF-1R are currently under study.EGFR inhibitors have exhibited single agent activity, and seem to synergize very well with standard chemotherapy except for cetuximab and 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX). Preliminary data suggests that EGFR inhibitors have similar effectiveness to vascular endothelial growth factor (VEGF) inhibitors in the first line setting. Skin toxicity remains the main limiting factor for the utilization of EGFR inhibitors, but strategies including the use of agents such as minocycline or doxycycline added to topical care seem to limit the severity of the rash.Key Words: Epidermal growth factor inhibitors (EGFR inhibitor), metastatic colorectal cancer (mCRC), cetuximab, panitumumab, KRAS, targeted therapy     

Bevacizumab-based therapies in the first-line treatment of metastatic colorectal cancer

Since its approval for the first-line treatment of metastatic colorectal cancer (mCRC), bevacizumab has become a standard treatment option in combination with chemotherapy for patients with mCRC. Bevacizumab has demonstrated efficacy in combination with a number of different backbone chemotherapy regimens, and its widespread use has introduced several important questions regarding the selection and optimization of bevacizumab-based treatment regimens, its use in various patient populations, and the identification of associated adverse events. This review discusses the results of several phase II and phase III clinical trials, as well as large observational studies, to address the use of bevacizumab in the treatment of patients with mCRC in the first-line setting.     

Role of endoglin and VEGF family expression in colorectal cancer prognosis and anti-angiogenic therapies

Colorectal cancer (CRC) is one of the cancer models and most of the carcinogenic steps are presently well understood. Therefore, successful preventive measures are currently used in medical practice. However, CRC is still an important public health problem as it is the third most common cancer and the fourth most frequent cause of cancer death worldwide. Nowadays, pathologic stage is a unique and well-recognized prognostic indicator, however, more accurate indicators of the biologic behavior of CRC are expected to improve the specificity of medical treatment. Angiogenesis plays an important role in the growth and progression of cancer but its role as a prognostic factor is still controversial. Probably the most important clinical implication of tumor angiogenesis is the development of anti-angiogenic therapy. The goal of this review is to critically evaluate the role of angiogenic markers, assessed by either endoglin-related microvessel density or expression of vascular endothelial growth factor family members in the CRC setting and discuss the role of these angiogenic markers in anti-angiogenic therapies.     

Therapeutic implications of resistance to molecular therapies in metastatic colorectal cancer

Metastatic colorectal cancer (mCRC) patients carrying KRAS mutated tumors do not benefit from epidermal growth factor receptor (EGFR)-targeted cetuximab- or panitumumab-based therapies. Indeed, the mutational status of KRAS is currently a validated predictive biomarker employed to select mCRC patients for EGFR targeted drugs. When patients fail standard 5-fluorouracil-, oxaliplatin-, irinotecan- and bevacizumab-based therapies, EGFR-targeted salvage therapy can be prescribed only for those individuals with KRAS wild-type cancer. Thus, clinicians are now facing the urgent issue of better understanding the biology of KRAS mutant disease, in order to devise novel effective therapies in such defined genetic setting. In addition to KRAS, recent data point out that BRAF and PIK3CA exon 20 mutations hamper response to EGFR-targeted treatment in mCRC, potentially excluding from treatment also patients with these molecular alterations in their tumor. This review will focus on current knowledge regarding the molecular landscape of mCRC including and beyond KRAS, and will summarize novel rationally-developed combinatorial regimens that are being evaluated in early clinical trials.     

Existing anti-angiogenic therapeutic strategies for patients with metastatic colorectal cancer progressing following first-line bevacizumab-based therapy

Continuous inhibition of angiogenesis beyond progression is an emerging treatment concept in the management of metastatic colorectal cancer patients with prior bevacizumab exposure. Treatment options include the continuation or reintroduction of bevacizumab during the second-line chemotherapy or switching to a different antiangiogenic monoclonal antibody such as aflibercept or ramucirumab. In the selection of treatment, patient-based factors such as performance status, age, tumor burden, and tolerance and sensitivity to the first-line bevacizumab-based therapy, as well as treatment-related factors such as toxicity, efficacy, and cost, should be taken into consideration.     

Nonresectional regional therapies for metastatic colorectal cancer to the liver

The liver is the second leading site of colorectal cancer metastases, following the lymph nodes. Although metastatic resection for colorectal cancer liver metastases has been shown to improve survival, many patients cannot undergo surgery. Several nonsurgical therapies are available in these situations, however high-quality evidence comparing the effectiveness of these therapies is sparse. Here, we review the currently available evidence in support of nonresectional regional therapies for colorectal metastases to the liver.     

Strategies of sequential therapies in unresectable metastatic colorectal cancer: a meta-analysis

Background

Before the emergence of first-line combination chemotherapy, the standard of care for unresectable metastatic colorectal cancer (mcrc) was first-line monotherapy with modulated 5-fluorouracil. Several large phase iii randomized controlled trials, now completed, have assessed whether a planned sequential chemotherapy strategy—beginning with fluoropyrimidine monotherapy until treatment failure, followed by another regimen (either monotherapy or combination chemotherapy) until treatment failure—could result in the same survival benefit produced with an upfront combination chemotherapy strategy, but with less toxicity for patients.

Methods

The medline and embase databases, and abstracts from meetings of the American Society for Clinical Oncology and the European Society for Medical Oncology, were searched for reports comparing a sequential strategy of chemotherapy with an upfront combination chemotherapy in adult patients with mcrc. Publications that reported efficacy or toxicity data (or both) were included.

Results

The five eligible trials that were identified included 4532 patients. A meta-analysis of those trials demonstrates a statistically significant survival advantage for combination chemotherapy (hazard ratio: 0.92; 95% confidence interval: 0.86 to 0.99). However, the median survival advantage (3–6 weeks in most trials) is small and of questionable clinical significance. Three trials reported first-line toxicities. Upfront combination chemotherapy results in significantly more neutropenia, febrile neutropenia, thrombocytopenia, diarrhea, nausea, vomiting, and sensory neuropathy. Sequential chemotherapy results in significantly more hand–foot syndrome.

Conclusions

Given the small survival advantage associated with upfront combination chemotherapy, planned sequential chemotherapy and upfront combination chemotherapy can both be considered treatment strategies. Treatment should be chosen on an individual basis considering patient and tumour characteristics, toxicity of each strategy, and patient preference.     

Consensus recommendations for the use of anti-egfr therapies in metastatic colorectal cancer

In January 2010, a panel of Canadian oncologists with particular expertise in colorectal cancer (crc) gathered to develop a consensus guideline on the use of therapies against the epidermal growth factor receptor (egfr) in the management of metastatic crc (mcrc). This paper uses a case-based approach to summarize the consensus recommendations developed during that meeting.These are the consensus recommendations:Testing for the KRAS status of the tumour should be performed as soon as an egfr inhibitor is being considered as an option for treatment.Anti-egfr therapies are not recommended for the treatment of patients with tumours showing mutated KRAS status.For a patient with wild-type KRAS and an Eastern Cooperative Oncology Group status of 0-2, whose mcrc has previously been treated with a fluoropyrimidine, irinotecan, and oxaliplatin, switching to an egfr inhibitor is a recommended strategy.Cetuximab, cetuximab plus irinotecan, and panitumumab are all options for third-line therapy in patients with wild-type KRAS, provided that tolerability is acceptable.     

Molecular subtypes of metastatic colorectal cancer are associated with patient response to irinotecan-based therapies

BackgroundCurrently, metastatic colorectal cancer is treated as a homogeneous disease and only RAS mutational status has been approved as a negative predictive factor in patients treated with cetuximab. The aim of this study was to evaluate if recently identified molecular subtypes of colon cancer are associated with response of metastatic patients to first-line therapy.Patients and methodsWe collected and analysed 143 samples of human colorectal tumours with complete clinical annotations, including the response to treatment. Gene expression profiling was used to classify patients in three to six classes using four different molecular classifications. Correlations between molecular subtypes, response to treatment, progression-free and overall survival were analysed.ResultsWe first demonstrated that the four previously described molecular classifications of colorectal cancer defined in non-metastatic patients also correctly classify stage IV patients. One of the classifications is strongly associated with response to FOLFIRI (P = 0.003), but not to FOLFOX (P = 0.911) and FOLFIRI + Bevacizumab (P = 0.190). In particular, we identify a molecular subtype representing 28% of the patients that shows an exceptionally high response rate to FOLFIRI (87.5%). These patients have a two-fold longer overall survival (40.1 months) when treated with FOLFIRI, as first-line regimen, instead of FOLFOX (18.6 months).ConclusionsOur results demonstrate the interest of molecular classifications to develop tailored therapies for patients with metastatic colorectal cancer and a strong impact of the first-line regimen on the overall survival of some patients. This however remains to be confirmed in a large prospective clinical trial.     

The evolving role of VEGF-targeted therapies in the treatment of metastatic colorectal cancer

Therapies that target angiogenesis and the VEGF pathway are a component of treatment for patients with metastatic colorectal cancer (mCRC). Bevacizumab is a humanized monoclonal antibody that binds to VEGFA. Chemotherapy plus bevacizumab has led to improved outcomes for mCRC patients. Despite these benefits, progressive disease invariably ensues. Multiple members of the VEGF family can potentially contribute to tumor angiogenesis and/or evasion of antiangiogenic therapy if one pathway should be inhibited. Aflibercept, a new biological agent, is a multiple angiogenic factor trap that prevents not only VEGFA, but also VEGFB and PlGF from activating their native receptors. Key clinical data for bevacizumab and aflibercept for treatment of mCRC, clinical evidence for use of these agents beyond progression, and the search for angiogenic biomarkers to better define patients most likely to benefit from these interventions will be reviewed.     

Biomarkers in the development of anti-angiogenic therapies for ovarian cancer

The treatment of ovarian cancer remains challenging as the majority of patients will relapse and die from their disease despite successful first-line treatment. New treatment strategies are needed and recently there has been an explosion of new agents being tested in ovarian cancer. Most of these are directed against molecularly defined pathways and a significant proportion target angiogenesis, an important process in the growth of ovarian cancer. We review the role of angiogenesis in the pathophysiology of ovarian cancer and discuss the development of the most promising anti-angiogenic drugs in this disease, including the first large phase III trials with bevacizumab which have demonstrated a disease-modifying role in ovarian cancer. Other studies with this drug and other inhibitors of the angiogenic pathways are underway in the first-line and recurrent disease settings. The financial cost of these agents, increased toxicity and requirement for prolonged therapy necessitates the urgent need to identify and validate biomarkers to guide the use of these drugs in the future. There are over 200 candidate biomarkers being studied in ovarian cancer. However, currently there are no validated biomarkers to predict response or progression of disease. In this review we present a selection of biomarkers that are under investigation and discuss their benefits and limitations.     

Liver-directed therapies in colorectal cancer

Colorectal cancer is the third leading cause of cancer-related deaths in the United States. Historically, the majority of patients that presented with metastatic disease to the liver were treated with systemic chemotherapy only but advances in imaging, surgical techniques, and non-resectional approaches have expanded the indications for liver-directed interventions. Current approaches used in patients with liver-only or liver-dominant metastatic disease include surgical resection, direct tumor ablation strategies, the use of intra-arterial infusions, and radiation therapies. The use of these liver-directed therapies in selected patients with colorectal liver metastases has led to significant improvements in overall survival. We review the clinical data and progress using liver-directed therapies in the treatment of colorectal liver metastases.     

Liver-directed therapies in colorectal cancer

The liver is the most common site of metastatic colorectal cancer (CRC) and the status of this organ is an important determinant of overall survival in patients with advanced disease. Complete resection of hepatic CRC metastases can provide a long-term cure for some patients, but the majority of liver metastases are not amenable to such surgery. Furthermore, most patients after curative resection ultimately suffer from recurrence, and the majority of such failures occur in the liver. Various ablative techniques can achieve local control of tumor after incomplete resection or for palliation. Tumor ablation currently has a secondary therapeutic role, as there is no evidence that it can achieve long-term survival comparable to surgical resection. Regional chemotherapy delivers tumoricidal agents in a selective fashion, minimizing systemic toxicity and damage to normal liver cells. Chemotherapy agents delivered through the hepatic artery can extend time to liver recurrence after curative resection and may prolong survival both in the adjuvant setting and when given to patients with unresectable disease. Molecular-based therapies, such as gene delivery and oncolytic viruses, provide promise for curative outcomes in patients with advanced disease.     

抗表皮生长因子受体单抗治疗晚期结直肠癌疗效预测因子的研究

 研究证实抗表皮生长因子受体（EGFR）单克隆抗体西妥昔单抗和帕尼单抗是晚期结直肠癌的有效治疗药物，采用免疫组织化学测定的EGFR表达强弱与临床疗效无关。介绍了目前有可能预测从西妥昔单抗或帕尼单抗治疗中受益的标志物，包括KRAS突变、EGFR拷贝数、EGFR配体（EGF、表皮调节素和双调蛋白）、细胞周期蛋白D1、IgG FcγR（FCGR2A-H131R和FCGR3A-V158F）和核因子κB。这些标志物将在避免抗EGFR治疗毒性、减少治疗费用方面起到重要作用。     

Biologic therapies in the metastatic colorectal cancer treatment continuum--applying current evidence to clinical practice

More therapeutic options are now available than ever before for patients with metastatic colorectal cancer (mCRC) and, as such, treatment decisions have become more complex. A multidisciplinary approach is, therefore, required to effectively manage these patients. In the past few years, many trials have reported on the value of combining biological agents, such as those targeting vascular endothelial growth factor A and epidermal growth factor receptors, with chemotherapy. However, despite the plethora of information now available, the optimal treatment strategy for patients with mCRC remains unclear. Indeed, the propensity of investigators to conduct clinical trials utilising a variety of chemotherapy backbones combined with the increased complexity of retrospectively incorporating analyses of genetic mutation status (e.g. KRAS and BRAF) have led to conflicting results for seemingly similar endpoints, particularly overall survival. As a result, guidelines that have been developed, whilst having some similarities, have distinct differences in terms of suggested therapeutic combinations. Therefore, here, we review and distil the currently available data reported from phase III trials of biologic agents in the first-, second- and third-line mCRC settings.