The role of mTOR signaling pathway in spinal cord injury

The mammalian target of rapamycin (mTOR) signaling pathway plays an important role in multiple cellular functions, such as cell metabolism, proliferation and survival. Many previous studies have shown that mTOR regulates both neuroprotective and neuroregenerative functions in trauma and various diseases in the central nervous system (CNS). Recently, we reported that inhibition of mTOR using rapamycin reduces neural tissue damage and locomotor impairment after spinal cord injury (SCI) in mice. Our results demonstrated that the administration of rapamycin at four hours after injury significantly increases the activity of autophagy and reduces neuronal loss and cell death in the injured spinal cord. Furthermore, rapamycin-treated mice show significantly better locomotor function in the hindlimbs following SCI than vehicle-treated mice. These findings indicate that the inhibition of mTOR signaling using rapamycin during the acute phase of SCI produces neuroprotective effects and reduces secondary damage at lesion sites. However, the role of mTOR signaling in injured spinal cords has not yet been fully elucidated. Various functions are regulated by mTOR signaling in the CNS, and multiple pathophysiological processes occur following SCI. Here, we discuss several unresolved issues and review the evidence from related articles regarding the role and mechanisms of the mTOR signaling pathway in neuroprotection and neuroregeneration after SCI.

Profiling mTOR pathway in neuroendocrine tumors

The serine/threonine kinase mammalian target of rapamycin (mTOR) plays a central role in regulating critical cellular processes such as growth, proliferation, and protein synthesis. The study of cancer predisposing syndromes within which neuroendocrine tumors (NETs) may arise has furnished clues on the involvement of mTOR pathway in sporadic diseases so far. Recent comprehensive analyses have definitely shown activation of mTOR pathway in both experimental and human sporadic NETs. Upstream regulators of mTOR (PTEN and TSC2) have been found mutated in sporadic pNETs. Activation of mTOR pathways in NETs is already demonstrated by expression profiles analysis that revealed downregulation of TSC2 gene and alterations of TSC2 and PTEN protein expression in the vast majority of well-differentiated tumors. Moreover, a global microRNA expression analysis revealed the overexpression, in highly aggressive tumors, of a microRNA (miR-21) that targets PTEN reducing its expression and therefore leading to mTOR activation as well. Overall, these clues have furnished the rationale for the use of mTOR inhibitors the treatment of pNETs. With the recent approval of Everolimus (mTOR-targeted drug) for the treatment of advanced pNETs, this paradigm has been effectively translated into the clinical setting. In this review, we discuss mTOR pathway involvement in NETs, the clinical evidence supporting the use of mTOR inhibitors in cancer treatment, and the current clinical issues that remain to be elucidated to improve patient management.

Profiling mTOR pathway in neuroendocrine tumors

The serine/threonine kinase mammalian target of rapamycin (mTOR) plays a central role in regulating critical cellular processes such as growth, proliferation, and protein synthesis. The study of cancer predisposing syndromes within which neuroendocrine tumors (NETs) may arise has furnished clues on the involvement of mTOR pathway in sporadic diseases so far. Recent comprehensive analyses have definitely shown activation of mTOR pathway in both experimental and human sporadic NETs. Upstream regulators of mTOR (PTEN and TSC2) have been found mutated in sporadic pNETs. Activation of mTOR pathways in NETs is already demonstrated by expression profiles analysis that revealed downregulation of TSC2 gene and alterations of TSC2 and PTEN protein expression in the vast majority of well-differentiated tumors. Moreover, a global microRNA expression analysis revealed the overexpression, in highly aggressive tumors, of a microRNA (miR-21) that targets PTEN reducing its expression and therefore leading to mTOR activation as well. Overall, these clues have furnished the rationale for the use of mTOR inhibitors the treatment of pNETs. With the recent approval of Everolimus (mTOR-targeted drug) for the treatment of advanced pNETs, this paradigm has been effectively translated into the clinical setting. In this review, we discuss mTOR pathway involvement in NETs, the clinical evidence supporting the use of mTOR inhibitors in cancer treatment, and the current clinical issues that remain to be elucidated to improve patient management.

Inhibition of mTOR in carcinoid tumors

Neuroendocrine neoplasms (NEN) are a heterogeneous group of tumors, whose incidence and prevalence are increasing. The clinical behavior of NEN is variable, ranging from well-differentiated slow growing tumors to highly aggressive poorly differentiated neuroendocrine carcinomas. The term carcinoid is commonly used for the more benign variants of these neoplasms. Most frequently, carcinoids have their origin in the small intestine, followed by in the lung and other sites. Some of these tumors are associated with the carcinoid syndrome. The use of somatostatin analogs has revolutionized the clinical management of patients with carcinoids. However, although symptomatic relief and stabilization of tumor growth for various periods of time are observed in many patients treated with somatostatin analogs, tumor regression is rare. Currently, there is no other powerful antiproliferative agent available for carcinoids. Mammalian target of rapamycin (mTOR), a main protein kinase in the phosphoinositide 3-kinase/Akt/p70S6K signaling pathway, is an important intracellular mediator involved in multiple cellular functions including proliferation, differentiation, apoptosis, tumorigenesis, and angiogenesis. Alterations of the normal activity of mTOR and of mTOR-related kinases in this pathway have been found in a diversity of human tumors, including NEN; therefore, mTOR pathway represents an attractive target for new anticancer therapies. While mTOR inhibitors, such as everolimus, are established therapy in pancreatic NEN, results from recent clinical trials indicate that mTOR inhibitors may be also of value in the management of carcinoids. However, further clinical trials will have to confirm efficacy and elucidate, in which subtypes and in which setting, these drugs might be most usefully applied.

Systemic therapy of neuroendocrine tumors of the lung

SUMMARY Pulmonary neuroendocrine tumors (pNETs) are normally included in trials comprising neuroendocrine tumors (NETs) of different organs of origin. Typical and atypical carcinoids are regarded as low-grade NETs and show low proliferation rates and minor responses with classic chemotherapy regimens. Somatostatin analogs were traditionally applied in patients with carcinoid syndrome and recently also demonstrated tumor response. Recently, novel agents such as sunitinib and everolimus showed improved survival in randomized studies. These trials contained only low numbers of pNETs. Another promising field of targeted therapy in low-grade NETs includes peptide receptor radionuclide therapy. High-grade pNETs include large-cell neuroendocrine carcinoma and small-cell lung cancer. We will discuss large-cell neuroendocrine carcinoma and will address small-cell lung cancer at the end of this review.

Efficacy of everolimus, a novel mTOR inhibitor, against basal-like triple-negative breast cancer cells

Patients with triple-negative breast cancers (TNBCs) typically have a poor prognosis because such cancers have no effective therapeutic targets, such as estrogen receptors for endocrine therapy or human epidermal growth factor receptor 2 (HER2) receptors for anti-HER2 therapy. As the phosphatidylinositol 3' kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) cascade is activated in TNBCs, mTOR is a potential molecular target for anticancer therapy. In this study, we investigated the antitumor activities of everolimus, an oral mTOR inhibitor, in nine TNBC cell lines. Everolimus effectively inhibited cell growth at concentrations under 100 nM (IC(50)) in five cell lines and even in the 1-nM range in three of the five cell lines. To identify specific characteristics that could be used as predictive markers of efficacy, we evaluated the expressions of proteins in the mTOR cascade, basal markers, and cancer stem cell markers using western blotting, fluorescent in situ hybridization (FISH), or immunohistochemistry. All five of the sensitive cell lines were categorized as a basal-like subtype positive for either epidermal growth factor receptor (EGFR) or CK5/6, although resistant cell lines were not of this subtype and tended to exhibit the characteristics of cancer stem cells, with decreased E-cadherin and the increased expression of Snail or Twist. In vivo assays demonstrated antitumor activity in a mouse xenograft model of basal-like breast cancer, rather than non-basal breast cancer. These results suggest that everolimus has favorable activity against basal-like subtypes of TNBCs. Epidermal growth factor receptor and CK5/6 are positive predictive markers of the TNBC response to everolimus, while cancer stem cell markers are negative predictive markers.

Characteristics and long-term survival of colorectal cancer patients aged 44 years and younger

BACKGROUND

This study was to investigate the clinicopathologic characteristics and prognosis of colorectal cancer (CRC) patients aged 44 years and younger.

METHODS

Patients were identified from a prospectively maintained CRC database and divided into two groups by age: younger and older group (≤44 and >44 years). Clinicopathologic characteristics and postoperative outcomes were compared.

RESULTS

There were 530 patients aged ≤44 years at diagnosis. More patients in the younger group had a family history of CRC compared with older patients. Younger patients were more likely than older patients to have larger tumours, infiltrative growth type tumours, poorly differentiated tumours, mucinous and signet-ring cell adenocarcinoma, and advanced TNM stages. Compared to older patients, more younger patients received chemotherapy and died of cancer-related causes. Overall survival, disease-free survival and cancer-specific survival of younger patients were comparable to older patients. Blood transfusion, TNM stage, histological grade and disease recurrence were independently associated with survival in the younger group.

CONCLUSIONS

Despite younger patients having unfavourable clinicopathologic features, younger age at diagnosis of CRC appears to be associated with similar oncologic outcomes as compared to older patients.

Temozolomide and unusual indications: review of literature

Temozolomide (TMZ) was first known to be useful as a radiosensitiser in both primary brain tumours like glioblastoma multiforme and oligodendroglioma. Later, TMZ proved its efficacy in the treatment of melanoma. Multiple publications have demonstrated the benefit of TMZ in terms of efficacy and tolerance (used as mono-therapy or as adjuvant chemotherapy) compared to the "gold standard" treatment of this kind of tumours. Furthermore, several recent clinical trials have shown the particular importance of TMZ in other types of cancer. This publication deals with the use of TMZ in cancers which are not formal indications for TMZ (excluding glioblastoma multiforme, oligodendroglioma and melanoma). It also includes a necessary review of recent literature about the role of TMZ in the treatment of brain metastases, lymphomas, refractory leukaemia, neuroendocrine tumours, pituitary tumours, Ewing's sarcoma, primitive neuroectodermal tumours, lung cancer and other tumours.

Current status and perspectives of targeted therapy in well-differentiated neuroendocrine tumors

Although neuroendocrine tumors (NET) are a relatively rare malignancy, the reported incidence is increasing, and some of the current treatment options are limited in their efficacy. Standard first-line therapy for metastatic small bowel NET includes somatostatin analogs. Although these agents can provide symptom relief and can delay disease progression in many patients, ultimately, new treatments are required for patients with progressive disease. In recent years, there has been considerable interest in developing agents specifically targeted against some of the pathways known to be involved in cancer cell growth, survival and invasion. In 2011, the mammalian target of rapamycin (mTOR) inhibitor everolimus and the tyrosine kinase inhibitor sunitinib were approved for the treatment of pancreatic NET. Clinical trials evaluating novel targeted agents are ongoing, both as single agents and in combination regimens. We review the current clinical status of these potential new treatments and highlight those with particular promise for the management of well-differentiated NET.

Phase 2 study of everolimus monotherapy in patients with nonfunctioning neuroendocrine tumors or pheochromocytomas/paragangliomas

BACKGROUND

The current study was conducted to evaluate the efficacy and safety of everolimus in the treatment of patients with nonfunctioning neuroendocrine tumors (NETs) or pheochromocytomas/paragangliomas.

METHODS

Patients with histologically confirmed nonfunctioning NETs or pheochromocytomas/paragangliomas and with documented disease progression before study enrollment were eligible for the current study. Everolimus was administered daily at a dose of 10 mg for 4 weeks. Response was assessed by Response Evaluation Criteria In Solid Tumors (RECIST; version 1.0) every 8 weeks. The primary endpoint was the 4-month progression-free survival rate (PFSR). The hypothesis of the current study was that the 4-month PFSR would increase from 50% to 65%. Safety was evaluated using the National Cancer Institute's Common Terminology Criteria for Adverse Events (version 3.0).

RESULTS

A total of 34 patients were enrolled. Of these, 27 patients had nonfunctioning NETs, 5 had pheochromocytomas, and 2 had paragangliomas. The 4-month PFSR was 78%. Partial response (PR) was observed in 3 patients. Twenty-eight patients had stable disease (SD) and 2 patients developed progressive disease (PD). The response rate (RR) and overall disease control rate (DCR) were 9.0% (95% confidence interval [95% CI], 0%-18.6%) and 93.9% (95% CI, 85.8%-100%), respectively. The PFS was 15.3 months (95% CI, 4.6 months-26.0 months). Of the patients with nonfunctioning NETs, 3 achieved a PR and 23 had SD (RR, 11.1%; DCR, 100%); the PFS was 17.1 months (95% CI, 11.1 months-23.0 months) and the 4-month PFSR was 90.0%. Twenty-one patients (80.8%) demonstrated tumor shrinkage. In 7 patients with pheochromocytomas/paragangliomas, 5 achieved SD, and 2 developed PD. The PFS was 3.8 months (95% CI, 0.5 months-7.0 months) and the 4-month PFSR was 42.9%. Four patients demonstrated tumor shrinkage. The major grade 3/4 adverse events were thrombocytopenia (14.7%), hyperglycemia (5.9%), stomatitis (5.9%), and anemia (5.9%).

CONCLUSIONS

Everolimus was associated with high therapeutic efficacy and tolerability in patients with nonfunctioning NETs, and demonstrated modest efficacy in patients with pheochromocytomas/paragangliomas.

Targeted therapy for gastric cancer--current status

In patients with metastatic gastric cancer, median overall survival remains under 1 year and standard chemotherapy regimens are not able to substantially improve the prognosis of the patients. Amplification and over-expression of HER2 is reported in approximately 20% of gastric tumours, challenging the use of targeted therapies. There are several targeted therapies in different stages of clinical development with trastuzumab being the first overcoming the regulatory hurdle and getting European Medicines Agency approval. In patients with advanced gastric or gastro-oesophageal junction cancer, addition of trastuzumab to chemotherapy significantly improved overall survival compared with chemotherapy alone. Addition of trastuzumab to chemotherapy did not increase the incidence of adverse events. Other agents targeting the HER2 pathway (lapatinib) or other domains of epidermal growth factor receptor family (cetuximab) are currently being investigated for the treatment of an advanced gastric cancer.

A review of penile metastasis

Penile cancer as primary disease is relatively rare in developed countries. The penis is a rare site of metastases in spite of its rich vascularization. Approximately 500 cases have been reported in the literature; almost 70% of primary lesions are of pelvic origin (from genitourinary or recto-sigmoid primary tumors). We describe a case of penile metastasis from lung cancer. The rarity of the event prompted us to also explore related reviews and discuss the incidence, physiopathology, diagnosis and therapy of penile secondary cancer.

Perifosine-mediated Akt inhibition in neuroendocrine tumor cells: role of specific Akt isoforms

The majority of neuroendocrine tumors (NETs) of the gastroenteropancreatic system show aberrant Akt activity. Several inhibitors of the phosphoinositide 3-kinase (PI(3)K)-Akt-mTOR signaling pathway are currently being evaluated in clinical phase II and III studies for the treatment of NETs with promising results. However, the molecular mechanisms and particularly the role of different Akt isoforms in NET signaling are not fully understood. In this study, we examine the effect of Akt inhibition on NET cells of heterogeneous origin. We show that the Akt inhibitor perifosine effectively inhibits Akt phosphorylation and cell viability in human pancreatic (BON1), bronchus (NCI-H727), and midgut (GOT1) NET cells. Perifosine treatment suppressed the phosphorylation of Akt downstream targets such as GSK3α/β, MDM2, and p70S6K and induced apoptosis. To further investigate the role of individual Akt isoforms for NET cell function, we specifically blocked Akt1, Akt2, and Akt3 via siRNA transfection. In contrast to Akt2 knockdown, knockdown of Akt isoforms 1 and 3 decreased phosphorylation levels of GSK3α/β, MDM2, and p70S6K and suppressed NET cell viability and colony-forming capacity. The inhibitory effect of simultaneous downregulation of Akt1 and Akt3 on tumor cell viability was significantly stronger than that caused by downregulation of all Akt isoforms, suggesting a particular role for Akt1 and Akt3 in NET signaling. Akt3 siRNA-induced apoptosis while all three isoform-specific siRNAs impaired BON1 cell invasion. Together, our data demonstrate potent antitumor effects of the pan-Akt inhibitor perifosine on NET cells in vitro and suggest that selective targeting of Akt1 and/or Akt3 might improve the therapeutic potential of Akt inhibition in NET disease.

Hitting the target: where do molecularly targeted therapies fit in the treatment scheduling of neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a rare and heterogeneous group of tumours whose incidence is increasing and their prevalence is now greater than that of any other upper gastrointestinal tumour. Diagnosis can be challenging, and up to 25% of patients present with metastatic disease. Following the recent FDA approval of two new molecularly targeted therapies for the treatment of advanced pancreatic NETs (pNETs), the first in 25 years, we review all systemic therapies and suggest where these newer targeted therapies fit in the treatment schedule for these challenging tumours. Clinical trial data relating to the routine use of sunitinib and everolimus in low-intermediate-grade pNETs are summarised alongside newer molecularly targeted agents undergoing clinical assessment in NETs. We particularly focus on the challenge of optimal scheduling of molecularly targeted treatments around existing systemic and localised treatment such as chemotherapy or radiotargeted therapy. We also discuss application of current evidence to subgroups of patients who have not so far been directly addressed such as those with poorer performance status or patients receiving radical surgery who may benefit from adjuvant treatment.

Metastatic signet ring colon cancer in a Caribbean young adult and review of the literature

Colorectal cancer is the third most common neoplasm diagnosed in the USA, with less than 3% of patients younger than 40 years. Although most of the literature indicates that younger patients present with a higher stage and grade of cancer, mortality is not clearly correlated. Furthermore, the literature pertaining to colorectal cancer in the nonwhite youth is limited. In this case report, we report a case of aggressive colorectal cancer metastasizing in a young Afro-Caribbean woman with no known risk factors. The aim of this report is to raise awareness of this entity in the younger population, particularly in Afro-Caribbeans, which remains a highly understudied group compared with the rest of the US population.

Factors associated with recurrence within 2 years after curative surgery for gastric adenocarcinoma

BACKGROUND

Despite curative surgery for gastric cancer, many patients die of recurrent cancer. Few studies have investigated the time to recurrence after curative resection for gastric cancer.

METHODS

Data were collected prospectively between December 1987 and December 2006. A total of 1,549 patients underwent curative resection of adenocarcinoma of the stomach at Taipei Veterans General Hospital. Among them, 419 patients had recurrence; they were divided into early recurrence (<2 years) and late recurrence (≥2 years). The clinicopathological characteristics, survival time after recurrence, and recurrence patterns were compared between the two groups.

RESULTS

Multivariate analysis showed that stage III gastric cancer patients with early recurrence had larger tumors and more lymph node metastasis than patients with late recurrence, while no difference between early and late recurrence was observed in stage I and II patients. Early recurrence was associated with more distant metastasis than was late recurrence. Patients with advanced TNM stage tended to die within 2 years after recurrence.

CONCLUSIONS

Gastric cancer patients with larger tumors and more lymph node metastasis tended to have early recurrence, especially stage III patients. Advanced TNM stage was associated with early cancer death after recurrence.

Antitumor effects of somatostatin analogs in neuroendocrine tumors

BACKGROUND

For decades, somatostatin analogs (including octreotide and lanreotide) have been indicated for relief of the symptoms of flushing, diarrhea, and wheezing associated with secretory neuroendocrine tumors (NETs). Recently, it has been suggested that somatostatin analogs may provide direct and indirect antitumor effects in secretory and nonsecretory NETs in addition to symptom control in secretory NETs.

METHODS

A systematic review of MEDLINE was conducted to identify studies that investigated the antitumor effects of octreotide or lanreotide for patients with NETs. Additional studies not published in the peer-reviewed literature were identified by searching online abstracts. Results. In all, 17 octreotide trials and 11 lanreotide trials that included antitumor effects were identified. Partial response rates were between 0% and 31%, and stable disease rates were between 15% and 89%. Octreotide was the only somatostatin analog for which results of a phase III, randomized, placebo-controlled clinical trial that investigated antitumor effects were published. After 6 months of treatment in this randomized phase III trial, stable disease was observed in 67% of patients (hazard ratio for time to disease progression: 0.34; 95% confidence interval: 0.20-0.59; p = .000072).

CONCLUSIONS

In addition to symptom control for NETs, the data support an antitumor effect of somatostatin analogs and suggest that they may slow tumor growth. Long-acting repeatable octreotide has been shown to have an antitumor effect in a randomized phase III trial in midgut NETs, whereas results are pending in a corresponding controlled trial with lanreotide for patients with intestinal and pancreatic primary NETs.

[Neuroendocrine tumors: the age of targeted therapies]

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are the second most prevalent group of advanced gastrointestinal tract tumors. Resources invested in research on this patient population have exponentially increased in recent years, and this has become one of the most attractive fields for oncological research. Several proangiogenic proteins have been found to be overexpressed in GEP-NETs, including vascular endothelial growth factor and its receptors and the more closely related intracellular signaling pathways such as the epidermal growth factor pathway, type I insulin-like growth factor receptor, and the PI3K-(PTEN)-AKT-mTOR pathway. The recent results of the three most important Phase III studies in GEP-NETs have allowed for approval of two targeted agents, sunitinib and everolimus, for the treatment of patients with pancreatic neuroendocrine tumors after decades of minimal advances in this population.

Loss of lactate dehydrogenase B subunit expression is correlated with tumour progression and independently predicts inferior disease-specific survival in urinary bladder urothelial carcinoma

AIMS

In our previous studies, comparative proteomics demonstrated that lactate dehydrogenase B subunit (LDH-B) is down-regulated in high grade compared to non-high grade urinary bladder urothelial carcinoma (UBUC). However, this finding has not been validated by clinical cohort investigation. Therefore, in the present study, 269 primary localised UBUC specimens were examined for LDH-B expression to clarify the relevance of LDH-B expression level to UBUC progression.

METHODS

Immunohistochemistry (IHC) was implemented to investigate LDH-B protein expression in 269 primary localised UBUC specimens and to evaluate the association with tumour progression and prognosis.

RESULTS

Our data demonstrated that dwindled LDH-B expression level was strongly associated with increment of primary tumour status (p < 0.0001), higher histological grade (p = 0.0024), and the presence of vascular (p = 0.0118) as well as perineurial (p = 0.0094) invasion, suggesting that LDH-B might be related to tumour progression. At the univariate level, low LDH-B expression is one of many parameters which significantly predicted both disease-specific survival (DSS) (p = 0.0001) and metastasis-free survival (MeFS) (p = 0.0024). In Cox multivariate regression model, higher pT status was the strongest independent prognosticator for both DSS (p = 0.0006) and MeFS (p = 0.0067) while low LDH-B expression remained prognostically significant for DSS (p = 0.0401).

CONCLUSION

The above results confirmed the prognostic roles of LDH-B in UBUC.

Therapy innovation for the treatment of pancreatic neuroendocrine tumors

INTRODUCTION

Traditional therapeutic approaches for patients with advanced neuroendocrine tumors (NETs) have included treatment with somatostatin analogs, hepatic-directed therapies, interferon and cytotoxic chemotherapy. Current knowledge about biological behavior of pancreatic neuroendocrine tumors (pNETs) has increased in the last decade, and some studies have been conducted to translate in the clinical setting. Among several molecular agents investigated in patients with progressive pNETs, everolimus and sunitinib have been studied in large Phase III trials. Both have produced significant benefit, with improvement in progression-free survival. These results were published last year by NEJM and were updated at the ASCO Annual Meeting in June 2011.

AREAS COVERED

This review focuses on the potential molecular targets in pancreatic NETs in the light of recent advances. Furthermore, it summarizes the available data for targeted agents from Phase II and III trials open to patients with this tumor.

EXPERT OPINION

These new agents are likely to play an increasingly important role in the future management of advanced pNETs. Their use in earlier phases of the disease could improve clinical outcome, avoiding side effects of the more toxic chemotherapy. The challenge in medical treatment of pNET is to define the patients who can benefit from this innovative therapy; future research should be directed to find predictive markers for response to the targeted agent.

A new era for the systemic therapy of neuroendocrine tumors

Carcinoids and pancreatic neuroendocrine tumors are becoming increasingly common, with the majority of patients presenting with either lymph node involvement or metastatic disease. An improved understanding of the molecular mechanisms involved in these tumors has implicated several pathways that have led to new therapeutic approaches. In this manuscript, we describe the biology of neuroendocrine tumors and approaches to systemic therapy. We review early data regarding the use of cytotoxics and several recent studies employing more targeted approaches that promise to change the standard of care. Specifically, phase III studies indicate that pharmacologic inhibition of the vascular endothelial growth factor pathway with sunitinib, and of the mammalian target of rapamycin pathway with everolimus, appears to have altered the natural history of these diseases. These successes set the stage for further advances in the management of patients with neuroendocrine tumors.

New strategies for advanced neuroendocrine tumors in the era of targeted therapy

Low- to intermediate-grade neuroendocrine tumor (NET) constitutes a group of indolent malignancies that share the capacity for secreting hormones and neuroamines. Until recently, there were few therapeutic options for oncologic control. The PROMID study showed that octreotide long-acting repeatable formulation can delay tumor growth in midgut NETs. And, recent phase III studies showed both everolimus and sunitinib improved progression-free survival in pancreatic NETs, validating the phosphoinositide 3-kinase/Akt/mTOR pathway and angiogenesis as important targets for further advances. Ongoing and planned pivotal studies targeting these pathways in other NET subtypes may widen their therapeutic application. Development of rational combinations may further improve therapeutic outcome. These successes and our improved understanding of the underlying molecular biology are likely to lead to further important advances on the horizon.

Medical treatment of gastroenteropancreatic neuroendocrine tumors

Treatment of the clinically and prognostically heterogeneous neuroendocrine neoplasms (NEN) should be based on a multidisciplinary approach, including surgical, interventional, medical and nuclear medicine-based therapeutic options. Medical therapies include somatostatin analogues, interferon-α, mTOR inhibitors, multikinase inhibitors and systemic chemotherapy. For the selection of the appropriate medical treatment the hormonal activity, primary tumor localization, tumor grading and growth behaviour as well as the extent of the disease must be considered. Somatostatin analogues are mainly indicated in hormonally active tumors for symptomatic relief, but antiproliferative effects have also been demonstrated, especially in well-differentiated intestinal NET. The efficacy of everolimus and sunitinib in patients with pancreatic neuroendocrine tumors (pNET) has been demonstrated in large placebo-controlled clinical trials. pNETs are also chemosensitive. Streptozocin-based chemotherapeutic regimens are regarded as current standard of care. Temozolomide in combination with capecitabine is an alternative that has shown promising results that need to be confirmed in larger trials. Currently, no comparative studies and no molecular markers are established that predict the response to medical treatment. Therefore the choice of treatment for each pNET patient is based on individual parameters taking into account the patient’s preference, expected side effects and established response criteria such as proliferation rate and tumor load. Platin-based chemotherapy is still the standard treatment for poorly differentiated neuroendocrine carcinomas. Clearly, there is an unmet need for new systemic treatment options in patients with extrapancreatic neuroendocrine tumors.

Pre-treatment lactate dehydrogenase levels as predictor of efficacy of first-line bevacizumab-based therapy in metastatic colorectal cancer patients

Background:

Lactate dehydrogenase (LDH) represents a predictive factor in colorectal cancer patients treated with the angiogenesis inhibitor PTK/ZK. We explored the role of pre-treatment LDH serum levels in colorectal cancer patients receiving first-line bevacizumab.

Methods:

Metastatic colorectal cancer treated with first-line bevacizumab was eligible. A control group including all consecutive patients treated with chemotherapy alone was also considered. Pre-treatment LDH serum levels were collected for all cases.

Results:

Median progression-free survival (PFS) in the control group for patients with high and low LDH levels was 4.2 and 8 months, respectively (P=0.0003). Median overall survival (OS) was 19.6 and 34.9 months for patients with high and low LDH levels, respectively (P=0.0014). In the bevacizumab group, partial responses were seen in 14 (58%) high-LDH and 8 (14%) low-LDH patients (P=0.0243), respectively, median PFS was 7.3 and 8.5 months, respectively (P=0.2), and median OS was 22 and 26.6 months, respectively (P=0.7).

Conclusion:

High LDH levels correlated with worse prognosis. Bevacizumab seemed capable of improving clinical outcome in this specific group of patients who usually present with an adverse natural history. The improved response rate also suggests a role for LDH as a predictive marker.

[Medicinal therapy of metastasized neuroendocrine tumors of the gastroenteropancreatic system.]

Neuroendocrine neoplasms of the gastroenteropancreatic system are classified according to the WHO classification system 2010 into neuroendocrine tumors (NET) and neuroendocrine carcinomas (NEC). The proliferation index Ki-67 and the grading of NETs is essential for the prognosis and therapy plan. Also NET tumor biology and therapeutic options may differ depending on the primary NET tumor location. Palliative therapy of inoperable NETs involves local ablative methods in cases of primary liver metastasis, peptide receptor radionuclide therapy (PRRT) in NETs expressing somatostatin receptors and different options for medicinal therapy. This manuscript reviews the current role of biotherapy with somatostatin analogues and interferon-alpha for symptom and tumor control. In addition conventional chemotherapy regimens and novel molecular targeted therapeutic options, such as sunitinib or everolimus in NET of the pancreas are reviewed. Possible therapeutic algorithms are discussed.

Emerging therapeutic options for advanced enteropancreatic neuroendocrine tumors

INTRODUCTION

Several chemotherapy agents and combinations have proven effective in the therapy of advanced enteropancreatic neuroendocrine tumors (EP-NETs). However, their toxicity can be significant. Recent understanding of the molecular mechanisms of these tumors, especially the central role of tumor angiogenesis, has led to the identification of new therapeutic targets and agents directed at the molecular level.

AREAS COVERED

This paper gives a comprehensive evaluation of the existing therapeutic armamentarium for EP-NETs. Narrated in a historical perspective, this review analyzes the available information on traditional chemotherapy agents, interferon-α and somatostatin analogs, as well as newer therapies and experimental agents.

EXPERT OPINION

Despite recent advances, a curative approach for metastatic EP-NETs is yet to be discovered. To date, sunitinib and everolimus have been shown to impact progression-free survival only in pancreatic NETs, and the duration of this benefit has not yet been established. Further research is necessary to determine whether a combination of these drugs, either together or with other therapies, may yield superior outcomes. Moreover, sequential use of these agents should be explored in an attempt to improve survival. Efficacy of a variety of experimental agents is also being tested in clinical trials.

Clinical significance of serum biomarkers in pediatric solid mediastinal and abdominal tumors

Childhood cancer is the leading cause of death by disease among U.S. children between infancy and age 15. Despite successes in treating solid tumors such as Wilms tumor, disappointments in the outcomes of high-risk solid tumors like neuroblastoma have precipitated efforts towards the early and accurate detection of these malignancies. This review summarizes available solid tumor serum biomarkers with a special focus on mediastinal and abdominal cancers in children.

Safety and efficacy of everolimus in adult patients with neuroendocrine tumors

Neuroendocrine tumors (NETs) consist of a diverse family of tumors which are derived from the neuroendocrine system. Most NETs are well or moderately differentiated tumors with a relatively indolent growth pattern. However, these tumors can cause significant clinical disease due to release of functional products that mediate the carcinoid syndrome and other diverse sequela. They also can grow progressively and cause symptoms from local invasion or distant metastasis. NETs are optimally treated with surgery and somatosatin analogs (SSA’s) to control symptoms but are relatively insensitive to systemic chemotherapy. As a result, patients with advanced unresectable NETs have a poor prognosis. In 2011, two targeted therapies, sunitinib and everolimus were approved in the subset of progressive pancreatic NETs (pNETs). Everolimus is an oral inhibitor of the growth stimulatory mTOR pathway. In Phase 2 trials in NETs and pNETs, everolimus was well tolerated and associated with some response and widespread disease stabilization. In follow-up, randomized Phase 3 trials, everolimus was compared to placebo. In the RADIANT-2 trial, everolimus and a somatostatin analog were used in patients with functional NETs and treatment was associated with an an improvement in progression-free survival (PFS). In the RADIANT-3 trial, patients with pNET were randomized to receive everolimus or placebo along with best supportive care. Everolimus was again associated with improvement in PFS compared to placebo and it has been approved by the FDA for patients with progressive pNET. Everolimus is associated with frequent low grade toxicity but is also notable for increased rates of infection as well as non-infectious pneumonitis. mTOR inhibition with everolimus represents a significant advance in the treatment of advanced neuroendocrine tumors.

Quality of clinical trials in gastroenteropancreatic neuroendocrine tumours

BACKGROUND

The heterogeneity of neuroendocrine tumours (NETs) makes interpretation of clinical trials in this disease challenging. Our aim was to review the quality of treatment trials in NETs in order to inform the design and reporting of future studies.

METHODS

We identified studies by searching MEDLINE. We considered all phase II and III trials of systemic antineoplastic treatments published between 2000 and 2011. Information on trial design, study population, end points, statistical considerations and results was abstracted from each article using a standardized form.

RESULTS

Seven phase III and 39 phase II trials were identified. The make-up of the study population was variable: only 24% of trials included patients with one type of tumour (pancreatic NET or carcinoid tumour), 41% included patients with both tumour types, and 35% of trials included other endocrine cancers. Disease progression at baseline was often not reported and was documented for all patients in 22% of the trials. The functional status of the tumour, tumour differentiation, and Ki67 index were reported in 35, 43, and 15% of trials, respectively. The primary end point was clearly defined in 72% of trials. Identifiable statistical design, and predefined sample size were reported in 74 and 61% of trials, respectively. Conflicts of interest and study sponsorship were reported in 46 and 85% of trials.

CONCLUSIONS

The quality of the design and reporting of phase II/III NET trials, as described in other cancers, is poor. Future trials should include more homogenous patient populations while adhering to rigorous selection, reporting and interpretation of population and trial parameters.

Hepatic arterial embolization versus chemoembolization in the treatment of liver metastases from well-differentiated midgut endocrine tumors: a prospective randomized study

BACKGROUND

Liver surgery is the best treatment for endocrine liver metastases, but it is often impossible due to diffuse disease. Systemic chemotherapy is poorly effective. Hepatic arterial embolization (HAE) and chemoembolization (HACE) have shown efficacy but have never been compared.

PATIENTS AND METHODS

Patients with progressive unresectable liver metastases from midgut endocrine tumors were randomly assigned to receive HAE or HACE (two procedures at 3-month interval). The primary end point was the 2-year progression-free survival (PFS) rate. Secondary end points were response rates, overall survival, and safety.

RESULTS

Twelve patients were assigned to receive HACE and 14 to receive HAE. The patient characteristics were well matched across the treatment arms. The 2-year PFS rates were 38 and 44% in the HACE and HAE arms, respectively (p = 0.90). Age, gender, previous resection of the primary tumor or liver metastases, extent of liver involvement, and concomitant treatment with somatostatin analogues were not associated with changes in PFS, whereas elevated baseline urinary 5-HIAA and serum chromogranin A levels were associated with shorter PFS. The 2-year overall survival rates were 80 and 100% in the HACE and HAE arms, respectively (p = 0.16). The disease control rate on CT scan was 95%. Grade 3 toxicity occurred in 19% of patients, with no treatment-related deaths and no differences in the treatment arms.

CONCLUSION

HACE and HAE are safe and permit tumor control in 95% of patients with progressive liver metastases from midgut endocrine tumors. The 2-year PFS was not higher among patients receiving HACE, not favoring the hypothesis of an additive efficacy of arterial chemotherapy or embolization alone.

Treatment of neuroendocrine tumor liver metastases

In the care of patients with hepatic neuroendocrine metastases, medical oncologists should work in multidisciplinary fashion with surgeons, interventional radiologists, and radiation oncologists to assess the potential utility of liver-directed and systemic therapies. This paper addresses the various roles and evidence basis for cytoreductive surgery, thermal ablation (radiofrequency, microwave, and cryoablation), and embolization (bland embolization (HAE), chemoembolization (HACE), and radioembolization) as liver-directed therapies. Somatostatin analogues, cytotoxic chemotherapy, and the newer agents everolimus and suntinib are discussed as a means for controlling intra- and extrahepatic disease, along with peptide receptor radiotherapy (PRRT). Finally, the experience with orthotopic liver transplant for neuroendocrine tumors is described.

Despite aggressive histopathology survival is not impaired in young patients with colorectal cancer : CRC in patients under 50 years of age

PURPOSE

Colorectal carcinoma (CRC) is generally a disease of persons older than 50 years. Concerning younger patients, controversies still exist regarding features and prognosis of CRC. We performed this study to characterize CRC in young patients (≤50 years) as well as to evaluate outcome in comparison with older patients (>50 years) with CRC.

METHODS

Clinical and histopathological parameters of 244 patients aged 50 years or less were compared with 1,718 patients aged more than 50 years.

RESULTS

Compared with older patients, the younger had less adenocarcinomas (82.8% vs. 89.1%; p = 0.004) and less postoperative complications (18.4% vs. 28.7%; p = 0.001), and less Union Internationale Contre le Cancer stage I colon cancers (22.9% vs. 13.6%, p = 0.046) but elevated overall 5-year survival rates for M0 colon and rectal cancers (p = 0.005; p < 0.001). In young patients, the minority suffered from hereditary cancer syndromes (7.4%) and inflammatory bowel diseases (7.0%). Furthermore, up to 40% of young patients denied any cancers in their families. Cancer-related survival rates were significantly elevated in young patients with M0 rectal carcinoma (p = 0.014), whereas in M0 colon cancers, no differences were detectable (p = 0.542). In case of the presence of distant metastases, overall and cancer-related survival rates were similar in old and young patients.

CONCLUSION

Although young patients present with more aggressive histopathological subtypes and less early stages, cancer-related survival is not less favourable compared with older patients.

Prognostic factors in patients with pancreatic cancer

The identification of prognostic factors for pancreatic cancer patients could provide insightful information for their management in the clinic. A total of 302 pancreatic cancer patients were enrolled in this study. The clinicopathological characteristics, treatment selection and laboratory test data were retrospectively retrieved from the medical records and follow-up data were obtained via telephone interview. Cox survival analysis was used to assess the potential prognostic factors, and survival curves were obtained by Kaplan-Meier analyses. The mortality rate of the patients was 83.4% (252/302) and the median survival of these patients was 6.1 months, with 1-, 2- and 3-year survival rates of 30.1 (91/302), 10.6 (32/302) and 2.6% (8/302), respectively. The most influential factors for the survival of these patients were the site of primary cancer, tumor stage, treatment selection, serum levels of glutamic-pyruvic transaminase, albumin, lactate dehydrogenase and hemoglobin, and white blood cell counts (P<0.05). The median survival of patients who did not receive any treatment or just received supportive treatment was 1.3 months, while the median overall survival of patients who underwent surgery, chemotherapy, biliary drainage therapy, arterial interventional chemotherapy and comprehensive treatment was 11.0, 7.3, 3.5, 9.0 and 11.0 months, respectively (P<0.05). Furthermore, single-drug chemotherapy was not statistically associated with patient survival in those who received the multi-drug regimen (P>0.05). However, the mortality risk of patients who received platinum chemotherapy was decreased [hazard ratio (HR)=0.56, 95% CI 0.35-0.88, P=0.011] compared to the patients who did not receive this treatment (P<0.05). Tumor stage, treatment selection, serum albumin levels, urea nitrogen, CA19-9, white blood cell and platelet counts were independent prognostic factors for the prediction of survival in pancreatic cancer. Future studies are required in order to verify these data. Chemotherapy with platinum regimens could improve overall survival in patients with pancreatic cancer.

Level of α-fetoprotein predicts mortality among patients with hepatitis C-related hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) can result from hepatitis C virus (HCV)-related liver disease and is the fastest-growing cause of cancer-related death in the United States. α-fetoprotein (AFP) has been used as a prognostic factor for HCC, but the value of AFP as a prognostic factor for HCV-related HCC in the United States is unknown. We investigated whether higher levels of AFP at the time of diagnosis are associated with increased mortality of patients with HCV-related HCC.

METHODS

In a retrospective study, we collected data from a cohort of HCV-infected veterans, identifying incident HCC cases from October 1, 1998, to January 1, 2007 (n = 1480 patients). The mean serum levels of AFP, obtained within 60 days before to 30 days after HCC diagnosis, were determined for 1064 patients and categorized as less than 10 ng/mL (18%), 10 to less than 100 ng/mL (30%), 100 to less than 1000 ng/mL (22%), or 1000 ng/mL or more (29%). Cox proportional hazard models were used to associate serum levels of AFP with mortality, adjusting for demographic features, clinical factors, and treatment.

RESULTS

The median survival times were significantly lower among patients with higher levels of AFP: 709 days for patients with less than 10 ng/mL, 422 days for patients with 10 to less than 100 ng/mL, 208 days for patients with 100 to less than 1000 ng/mL, and 68 days for patients with 1000 ng/mL or more. In the multivariate analysis, increased levels of AFP (10 to <100, 100 to <1000, and ≥1000) were associated significantly with increased mortality, compared with a serum AFP level of less than 10; hazard ratios were 1.50, 2.23, and 4.35, respectively.

CONCLUSIONS

Serum AFP level at the time of diagnosis with HCV-related HCC is an independent predictor of mortality.

Clinicopathological analysis for recurrence of stage Ib gastric cancer (according to the second English edition of the Japanese classification of gastric carcinoma)

BACKGROUND

The prognosis for patients with stage Ib (second English edition of the Japanese classification of gastric carcinoma) gastric cancer is promising, with an expected 5-year survival of 90%. Despite this relatively high survival rate, the outcome for patients who experience recurrence is poor. To date, however, prognostic and recurrence factors for stage Ib gastric cancer are poorly understood, and appropriate adjuvant chemotherapy protocols have not been developed.

METHODS

We retrospectively analyzed data from 86 stage Ib gastric cancer patients who underwent curative gastrectomy to determine the rates and predictive factors of recurrence.

RESULTS

Eleven patients showed recurrence, with a 12.8% 5-year cumulative recurrence rate. Nearly all of these patients were initially histologically diagnosed with poorly differentiated adenocarcinoma. Based on univariate analyses, recurrence was associated with gender and histological type. Multivariate analyses revealed that the only independent risk factor for recurrence was histologically undifferentiated-type adenocarcinoma. The 5-year survival rate of patients with undifferentiated-type adenocarcinoma was 84%. The predominant recurrence pattern was peritoneal dissemination, and was typically observed 1-3 years post-resection.

CONCLUSION

This retrospective study identified undifferentiated-type adenocarcinoma as the only risk factor for recurrence in stage Ib gastric cancer patients. Although randomized controlled studies are necessary, stage Ib gastric cancer patients with this identified recurrence risk factor would be candidates for adjuvant chemotherapy.

Long-term survival benefits of adjuvant chemotherapy by decreasing incidence of tumor recurrence without delaying relapse in stage III colorectal cancer

BACKGROUNDS AND AIMS

To elucidate the survival benefits of adjuvant chemotherapy by decreasing incidence or by delaying time of tumor recurrence, we reported the long-term results of a nonrandomized prospective study comparing the adjuvant chemotherapy to no chemotherapy in stage III colorectal cancer.

PATIENTS

From 1991 to 1995, 463 patients with stage III colorectal cancer were divided to three groups which were no chemotherapy, weekly chemotherapy, and monthly chemotherapy (5-FU plus levamisole).

RESULTS

The recurrent incidence was significantly decreased in patients with chemotherapy (47.8% vs. 63.9% of no chemotherapy, P = 0.001), resulting into better survival. The 10-year cancer-specific and overall survival rates of patients with chemotherapy vs. no chemotherapy were 52.1% vs. 37.8% and 46.9% vs. 29.9%, respectively (P < 0.001). Weekly chemotherapy had better survival than monthly chemotherapy (P < 0.05). There was no significant difference in recurrent time or types between the patients with and without chemotherapy. The percentages of patients with recurrence happened within 3 years were 85.2% and 84.6% of those with and without chemotherapy, respectively. Patients with advanced stage of T4b invasion depth, N2, and central node invasion had no significant survival benefits by adjuvant chemotherapy.

CONCLUSIONS

Long-term survival benefits achieved by adjuvant chemotherapy is through decreasing recurrent incidence, not through postponing tumor recurrent time. That means adjuvant chemotherapy indeed cures some patients by eradicating occult tumor. In adjuvant setting, more powerful regimen for eradicating occult tumor is the keystone to improve long-term survival of stage III colorectal cancer.

Simplified prognostic model in patients with oxaliplatin-based or irinotecan-based first-line chemotherapy for metastatic colorectal cancer: a GERCOR study

BACKGROUND

The present study was done to establish a prognostic model for patients and trials using an oxaliplatin-based or irinotecan-based first-line chemotherapy in metastatic colorectal cancer.

PATIENTS AND METHODS

Eight hundred three patients treated with FOLFOX or FOLFIRI in three prospective trials were randomly separated into learning (n = 535) and validation (n = 268) samples. Eleven baseline variables were evaluated in univariate and multivariate analysis as prognostic factors for overall survival, and a prognostic score was developed.

RESULTS

Independent prognostic factors identified in multivariate analysis for overall survival were performance status (PS) (p < .001), serum lactate dehydrogenase (LDH) (p < .001), and number of metastatic sites (p = .005). A prognostic score based on these three variables was found efficient (Harrell's C index 0.61). This new model was improved by selecting only PS and LDH (Harrell's C index 0.64). Three risk groups for death could be identified: a low-risk group (n = 184; median overall survival [OS] 29.8 months), an intermediate-risk group (n = 223; median OS 19.5 months), and a high-risk group (n = 128; median OS 13.9 months). Median survival for the low-, intermediate-, and high-risk groups were 26.8, 21.1, and 16.5 months, respectively, in the validation sample (Harrell's C index 0.63).

CONCLUSIONS

Serum LDH level was the main prognostic factor in predicting survival, followed by WHO PS. We identified three risk groups for death depending on these two baseline parameters. This simple prognostic model can be useful for clinician's use and patient stratification in future clinical trials.

Postoperative intraperitoneal 5-fluoro-2'-deoxyuridine added to chemoradiation in patients curatively resected (R0) for locally advanced gastric and gastroesophageal junction adenocarcinoma

PURPOSE

Chemoradiation after surgery for locally advanced gastric cancer improves overall and relapse-free survival compared with observation. However, locoregional recurrences remain high. Accordingly, we instituted this pilot/feasibility study, including intraperitoneal 5-fluoro-2'-deoxyuridine (IP FUDR) as part of the treatment.

METHODS

Gastric/gastroesophageal junction adenocarcinoma stage Ib-IV (M0) patients who underwent R(0) resection were eligible and had IP catheters inserted at time of surgery. IP FUDR (3 g/dose/day) was given during study days 1-3 and 15-17 before combined 5-fluorouracil, leucovorin, and external beam radiation (45 Gy). Endpoints included toxicity, completion rate, locoregional recurrence, and survival.

RESULTS

Twenty-eight patients (22 men) were enrolled from 2002-2006 at two institutions; their median age was 59.5 years. After R(0) resection, a median 22 (range, 8-102) lymph nodes were examined, and 22 patients had positive nodes. AJCC stages were IB (n = 8), II (n = 10), IIIA (n = 5), IIIB (n = 1), and IV (n = 4). Full-dose IP FUDR and chemoradiation treatment was completed in 20 and 25 patients, respectively. At nearly 4-year median follow-up, 11 patients were disease-free, 5 were alive with disease, 7 were dead of disease, and 1 was dead from other cause; 4 have been lost to follow-up. Recurrences were local in one, intra-abdominal in six, distant in two, multiple sites in two, and unknown in one. The median relapse-free survival is 65.3 months, and the median overall survival has not yet been reached.

CONCLUSIONS

IP FUDR before chemoradiation after R(0) gastric cancer resection is well tolerated without compromising completion of postoperative adjuvant treatment. Larger randomized trials studying IP FUDR as part of gastric cancer multidisciplinary treatment are needed to prove efficacy in reducing regional recurrence and improving survival.