Search

The systemic management of patients with pancreatic neuroendocrine tumors includes chemotherapy and targeted agents such as everolimus and sunitinib. Which treatment to favor in a particular patient is not known. The most commonly used chemotherapy agents are streptozocin and temozolamide, often prescribed in combination with fluoropyrimidines. A potential biomarker for selection of temozolomide-based chemotherapy is O-6-methylguanine-DNA-methyltrasferase expression. Chemotherapy yields higher response rates and may be preferable in patients with higher-grade tumors and those who are symptomatic. The mammalian target of rapamycin inhibitor everolimus has shown improvement in progression-free survival (PFS) in a robust, well-conducted phase III study. Everolimus, however, can induce limiting toxicities that may result in treatment discontinuation and does not improve survival. However, the objective response rate is very low. Sunitinib, likewise, increases PFS but the data comes from a smaller trial which was terminated early. Sunitinib displays a different toxicity profile and is associated with a trend towards improved overall survival. It is clear that biomarkers to properly select the most effective agents in an individual patient are needed.

The molecular events of tumorigenesis in neuroendocrine tumors are poorly understood. Understanding of the molecular alterations will lead to the identification of molecular markers, providing new targets for therapeutics. The purpose of this review was to critically analyze the genetic abnormalities in neuroendocrine tumors, with the aim of identifying biomarkers that indicate a response to agents developed against these targets and to serve as an understanding for the combinations of different active compounds. Human epidermal growth factor receptor 1/2 (EGFR and HER2), vascular endothelial growth factor receptors, hepatocyte growth factor receptor (c-Met), platelet-derived growth factor receptor, insulin-like growth factor, phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway, and heat shock proteins are all interesting candidate biomarkers with involvement in carcinogenesis and tumor evolution of several neoplasms, including neuroendocrine tumors. Some of them have already been evaluated both as targets and also as biomarkers in clinical trials conducted in advanced neuroendocrine tumor settings, and others should encourage further investigations into innovative therapeutic opportunities.

Pharmacogenomics is the study of how variation in the genetic background affects an individual's response to a specific drug and/or its metabolism. Using knowledge about the genes which produce the enzymes that metabolize a specific drug, a physician may decide to raise or lower the dose, or even change to a different drug. Targeted therapy with tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin (mTOR) inhibitors has led to a substantial improvement in the standard of care for patients with advanced or metastatic renal cell carcinoma (RCC). Although few studies have identified biomarkers that predict the response of targeted drugs in the treatment of metastatic RCC, some associations have been found. Several studies have identified genetic polymorphisms with implications in the pharmacokinetics and/or pharmacodynamics of TKIs and mTOR inhibitors and which are associated with a prolonged progression-free survival and/or overall survival in patients with metastatic RCC. Among the genes of interest, we should consider IL8, FGFR2, VEGFA, FLT4, and NR1I2. In this review, we discuss single nucleotide polymorphisms (SNPs) associated with outcome and toxicity following targeted therapies and provide recommendations for future trials to facilitate the use of SNPs in personalized therapy for this disease.

Neuroendocrine tumors (NETs) comprise a broad range of neoplasms that share biological and embryological origin. A deeper knowledge in the underlying molecular biology that results in the development and spread of NETs has allowed the use of novel-targeted therapies against angiogenesis and intracellular pathways, key checkpoints that govern growth, and proliferation of these tumors. Unfortunately, the possibility of cure is still far for patients with advanced stages. Cancer stem cells (CSCs) are present in most solid tumors. Nevertheless, there is limited evidence for the presence of CSCs in NETs. In this review, we will discuss the embryonic origin and possible existence of a gastroenteropancreatic neuroendocrine cancer stem cell. Here, we summarize the body of evidence supporting the presence of active embryological pathways like Notch, Wnt-β-catenin, Hedgehog, or transforming growth factor-β in NETs. New therapeutic approaches in the field of CSCs seem to have a clear role in the treatment of medulloblastomas and basal cell carcinomas, but their future value in other solid tumor types including NETs remains unclear.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) show limited sensitivity to cytotoxic agents, requiring the search for novel therapies. Recently, data from a phase III trial demonstrated that sunitinib produces a clinically significant improvement in progression-free survival in patients with unresectable, advanced, or metastatic GEP-NETs. Based on this finding, sunitinib became the first targeted drug approved for the treatment of GEP-NETs, paving the way for the approval of other anticancer agents in this drug-orphan disease. To date, results of trials involving other multitargeted tyrosine kinase inhibitors, such as sorafenib, the monoclonal antibody bevacizumab, and insulin-like growth factor 1 receptor inhibitors, have also shown promising results, and some are already being studied in phase III trials. This review updates the results of ongoing trials using inhibitors of growth factors and tyrosine kinase receptors involved in the carcinogenesis of GEP-NETs.

Neuroendocrine tumors (NETs) consist of a heterogeneous group of malignancies with various clinical presentations and growth rates. The incidence has been estimated to 2.5-5 per 100,000 people per year and prevalence of 35 per 100,000. The largest group is the gastroenteropancreatic NETs. Small intestinal NETs are the most common followed by pancreatic NETs in the gastrointestinal tract. A classification system (World Health Organization) was established in year 2000 and recently updated in 2010, taking into consideration the histopathology and tumor biology of the tumors. To further refine the classification a "tumor node metastasis" staging has been suggested by the European Neuroendocrine Tumor Society. The same organization has also proposed a grading system (G1, G2, and G3). The diagnosis of a NET is based on histopathology on tumor specimens, circulating biomarkers as well as imaging. Traditional radiology, such as computerized tomography and magnetic resonance imaging, is still the basis but is complemented with somatostatin receptor scintigraphy and positron emission tomography with specific isotopes such (68)Ga-DOTA-octreotate, F18-dopamine, or C11-5 hydroxytryptamine. Molecular imaging will increase in importance in the near future. There is still an unmet need for more sensitive biomarkers for diagnosis and follow-up.

In the last 30 years the incidence and prevalence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased substantially. This could be partly due to improvements in diagnostic imaging, which lead to the incidental diagnosis of asymptomatic cases. However, despite these improvements, patients typically experience long delays before they are diagnosed. In this review, we discuss both the limitations and advances in our understanding of the pathogenesis, molecular and cellular biology, diagnosis, classification, staging, and treatment of GEP-NETs in order to identify which factors could be contributing to the delay in diagnosis and timely treatment of these patients. Within this context, the results from the most relevant clinical trials the available targeted therapies for the treatment of GEP-NETs, such as the "RAD001 in Advanced Neuroendocrine Tumors," will be discussed.

Elderly or frail patients are often excluded from clinical trials. As a result, clinical outcome of these patients may differ from those obtained in trials. This situation may also hold true for patients who have severe concomitant diseases such as renal, hepatic, or cardiac dysfunction. Being aware of the wide range of clinical situations that a specialist may face is important to ensure that under any circumstances, the patient will receive the best treatment possible. The Spanish Oncology Genitourinary Group issued its first public statement on recommendations for the optimal management of advanced renal cell carcinoma (RCC). However, some issues remained unsolved. In this report, we discuss the current role of Medical Oncology in the treatment of patients with advanced RCC and review the management of special patient populations, such as elderly or patients with concomitant diseases.

The speed at which targeted therapies are being developed and incorporated into the treatment of advanced renal cell carcinoma (RCC) is surprising. After decades in which the only systemic treatment options available for advanced disease were interleukin-2 and interferon-alpha, in the last decade, six new targeted therapies have emerged showing meaningful clinical benefits to patients with advanced RCC through phase III trials. Recently, the Spanish Oncology Genitourinary Group issued its first public statement of recommendations for the optimal management of advanced RCC. However, most pivotal phase III trials on which these recommendations were based have been updated and/or fully reported. Moreover, a new multikinase inhibitor, pazopanib, has emerged with good quality clinical data. In this report, we review in depth the latest phase III data of targeted therapies for advanced RCC and update our recommendations. Furthermore, we hypothesize about the best environment for patients with advanced RCC to receive cancer therapy.