Combination of LHRH analog with somatostatin analog and dexamethasone versus chemotherapy in hormone-refractory prostate cancer: a randomized phase II study

Clinical Efficacy of a Novel Therapeutic Principle, Anakoinosis

Classic tumor therapy, consisting of cytotoxic agents and/or targeted therapy, has not overcome therapeutic limitations like poor risk genetic parameters, genetic heterogeneity at different metastatic sites or the problem of undruggable targets. Here we summarize data and trials principally following a completely different treatment concept tackling systems biologic processes: the principle of communicative reprogramming of tumor tissues, i.e., anakoinosis (ancient greek for communication), aims at establishing novel communicative behavior of tumor tissue, the hosting organ and organism via re-modeling gene expression, thus recovering differentiation, and apoptosis competence leading to cancer control - in contrast to an immediate, "poisoning" with maximal tolerable doses of targeted or cytotoxic therapies. Therefore, we introduce the term "Master modulators" for drugs or drug combinations promoting evolutionary processes or regulating homeostatic pathways. These "master modulators" comprise a broad diversity of drugs, characterized by the capacity for reprogramming tumor tissues, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs etc., or for example differentiation inducing therapies. Data on 97 anakoinosis inducing schedules indicate a favorable toxicity profile: The combined administration of master modulators, frequently (with poor or no monoactivity) may even induce continuous complete remission in refractory metastatic neoplasia, irrespectively of the tumor type. That means recessive components of the tumor, successively developing during tumor ontogenesis, are accessible by regulatory active drug combinations in a therapeutically meaningful way. Drug selection is now dependent on situative systems characteristics, to less extent histology dependent. To sum up, anakoinosis represents a new substantive therapy principle besides novel targeted therapies.

Phase I Trial of the Combination of Docetaxel, Prednisone, and Pasireotide in Metastatic Castrate-Resistant Prostate Cancer

BACKGROUND

Pasireotide (SOM230; Novartis Inc, Basel, Switzerland) is a multitargeted somatostatin receptor analogue likely to treat the neuroendocrine, and docetaxel resistant components within metastatic castrate-resistant prostate cancer (mCRPC). This phase I trial tested the combination of pasireotide, docetaxel, and prednisone in pretreated mCRPC.

PATIENTS AND METHODS

Chemotherapy naive mCRPC patients received docetaxel 75 mg/m² intravenously every 21 days and pasireotide intramuscularly every 28 days at escalating dose levels of 40, 60, and 80 mg. Maximum tolerated dose and recommended phase II dose (RP2D) were assessed.

RESULTS

Eighteen patients were enrolled with a median age of 65 (range, 49-75) years, and pretherapy prostate-specific antigen of 259.9 ng/mL. The dose-limiting toxicities were Grade 4 hyperglycemia unresponsive to therapy and Grade 4 neutropenia lasting for > 7 days in 1 patient each occurring at the 80-mg dose level of pasireotide. The RP2D was determined at 60 mg every 28 days. Four patients at the 60 mg dose had Grade 3 or 4 hyperglycemia, which responded adequately to therapy. Median time to progression and survival were 7.2 and 18.3 months, respectively. Three of 6 patients with circulating tumor cells ≥5 converted to circulating tumor cells < 5 post therapy. The insulin like growth factor-1 levels revealed a median 51% decrease after therapy. The neuron-specific enolase and chromogranin did not show any marked change.

CONCLUSION

The addition of pasireotide to docetaxel and prednisone is clinically feasible at a dose level of 60 mg every 28 days. The combination showed potential for clinical efficacy but needs to be compared with the standard docetaxel and prednisone regimen.

Adriamycin in combination with dexamethasone and octreotide lacks activity on the treatment of a 4T1 metastatic breast cancer model

The aim of this study was to evaluate whether the palliative treatment for metastatic disease with dexamethasone (DEX) plus octreotide (OCT) can improve the anticancer effects of the standard treatment with adriamycin (ADR) on a 4T1 metastatic breast cancer (MBC) model. 4T1 cells were first characterized for the expression of the somatostatin receptors 1-5 and were then inoculated onto the femur of BALB/C mice. Investigation protocols used 4T1 cell proliferation and invasion assays, analysis of radiographic images of the bone metastatic lesions, and overall survival of the diseased animals. The triple combination treatment regime (ADR+OCT+DEX) was ineffective for growth inhibition and showed an antagonistic effect on ADR activity in the 4T1 cell line in both proliferation and invasion assays. ADR treatment following the administration of the DEX+OCT regimen decreased the anticancer activity of ADR both on the grading of the bone metastatic lesions and on the overall survival of diseased animals. Moreover, the palliation treatment with OCT+DEX and in combination with ADR rather caused disease progression of the metastatic disease and bone lesions in a 4T1 MBC model in vivo. These results suggest that the administration of the DEX+OCT regimen, although may preserve palliative effects, neutralizes or reverses the anticancer effects of ADR on a 4T1 MBC model in vitro and in vivo. The simultaneous use of these drugs should be considered carefully in clinical practice.

Alopecia with endocrine therapies in patients with cancer

BACKGROUND

Whereas the frequency of alopecia to cytotoxic chemotherapies has been well described, the incidence of alopecia during endocrine therapies (i.e., anti-estrogens, aromatase inhibitors) has not been investigated. Endocrine agents are widely used in the treatment and prevention of many solid tumors, principally those of the breast and prostate. Adherence to these therapies is suboptimal, in part because of toxicities. We performed a systematic analysis of the literature to ascertain the incidence and risk for alopecia in patients receiving endocrine therapies.

METHODS

An independent search of citations was conducted using the PubMed database for all literature as of February 2013. Phase II-III studies using the terms "tamoxifen," "toremifene," "raloxifene," "anastrozole," "letrozole," "exemestane," "fulvestrant," "leuprolide," "flutamide," "bicalutamide," "nilutamide," "fluoxymesterone," "estradiol," "octreotide," "megestrol," "medroxyprogesterone acetate," "enzalutamide," and "abiraterone" were searched.

RESULTS

Data from 19,430 patients in 35 clinical trials were available for analysis. Of these, 13,415 patients had received endocrine treatments and 6,015 patients served as controls. The incidence of all-grade alopecia ranged from 0% to 25%, with an overall incidence of 4.4% (95% confidence interval: 3.3%-5.9%). The highest incidence of all-grade alopecia was observed in patients treated with tamoxifen in a phase II trial (25.4%); similarly, the overall incidence of grade 2 alopecia by meta-analysis was highest with tamoxifen (6.4%). The overall relative risk of alopecia in comparison with placebo was 12.88 (p < .001), with selective estrogen receptor modulators having the highest risk.

CONCLUSION

Alopecia is a common yet underreported adverse event of endocrine-based cancer therapies. Their long-term use heightens the importance of this condition on patients' quality of life. These findings are critical for pretherapy counseling, the identification of risk factors, and the development of interventions that could enhance adherence and mitigate this psychosocially difficult event.

Bone microenvironment-targeted manipulations for the treatment of osteoblastic metastasis in castration-resistant prostate cancer

INTRODUCTION

Most patients with advanced prostate cancer will develop incurable bone metastasis. Although prostate cancer is the quintessential androgen-dependent neoplastic disease in males, the tumor will ultimately become refractory to androgen ablation treatment. Understanding the complex dialog between prostate cancer and the bone microenvironment has allowed the development of promising treatment strategies.

AREAS COVERED

The present review summarizes the pathophysiology of prostate cancer bone metastasis and provides a concise update on bone microenvironment-targeted therapies for prostate cancer. The current and future prospects and challenges of these strategies are also discussed.

EXPERT OPINION

A wide variety of signaling pathways, bone turnover homeostatic mechanisms and immunoregulatory networks are potential targets for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Anti-survival factor therapy can enhance the efficacy of existing treatment regimens for mCRPC by exploiting the interaction between the bone microenvironment and androgen signaling networks. In addition, many novel bone microenvironment-targeted strategies have produced promising objective clinical responses. Further elucidation of the complex interactions between prostate cancer cells and the bone stroma will open up new avenues for treatment interventions that can produce sustained cancer suppression.

Differential molecular mechanism of docetaxel-octreotide combined treatment according to the docetaxel-resistance status in PC3 prostate cancer cells

To examine the effect and the molecular mechanisms of the combined treatment of the somatostatin (SST) analogue octreotide with docetaxel: analysis of proliferation, apoptosis and migration in the human prostate cancer cell line PC3, either sensitive (PC3wt) or made resistant to docetaxel (PC3R). We examined the effect of the two drugs individually or in combination on cell proliferation and migration by analysis of apoptosis and cell cycle proteins. The role of octreotide in modulating P-glycoprotein function was examined together with the modulation of SST receptors type 2 and 5 (SSTR2 and SSTR5). We observed an enhanced effect of docetaxel and octreotide given in combination or in sequence compared with either agent alone; this result was particularly evident when docetaxel was given before octreotide in PC3wt and when the two drugs were given together in PC3R cells. In contrast to lanreotide, our data indicate that octreotide does not act as a P-glycoprotein inhibitor in PC3R cells. A role of docetaxel and combined treatment in regulating SSTR2, SSTR5, proliferation and apoptosis gene expression is suggested as the possible mechanism for the enhanced effect observed. In addition, an evaluation of the effect of the combined treatment on cellular migration was examined, showing a moderate loss of invasive properties in PC3R cells. The present results confirm that SST analogues may be combined with docetaxel to increase the antitumour effect in patients with advanced prostate carcinoma.

A review of the use of somatostatin analogs in oncology

Somatostatin is a neuropeptide produced by paracrine cells that are located throughout the gastrointestinal tract, lung, and pancreas, and is also found in various locations of the nervous system. It exerts neural control over many physiological functions including inhibition of gastrointestinal endocrine secretion through its receptors. Potent and biologically stable analogs of somatostatin have been developed. These somatostatin analogs show different efficacy on different receptors, and receptors are varyingly concentrated in specific tissues. Antitumor and antisecretory effects of somatostatin analogs in cancer have been shown in several in vivo and in vitro studies. However, these activities have not always yielded into clinically relevant patient outcome benefit. Somatostatin analogs are of clinical benefit in treating symptoms of ectopic hormone secretion (adrenocorticotropic hormone, growth hormone-releasing hormone) in lung cancer, without inducing a significant tumor response. They have also been shown to induce a statistically significant decrease in bone pain and increase in Karnofsky performance status in patients with metastatic prostate cancer. Somatostatin analogs alone or in combination with other agents have only limited antitumoral effect in breast cancer. In gastrointestinal cancers, studies have not shown an objective tumor response to somatostatin analogs except in endocrine tumors of the liver with symptomatic and biochemical improvement. In neuroendocrine tumors of the gastrointestinal system and pancreas, very high symptomatic and biochemical response rates have been achieved with somatostatin analogs. Antiproliferative activity has been clearly shown in metastatic midgut neuroendocrine tumors.

Evidence for the Possible Biological Significance of the igf-1 Gene Alternative Splicing in Prostate Cancer

Insulin-like growth factor-I (IGF-I) has been implicated in the pathogenesis of prostate cancer (PCa), since it plays a key role in cell proliferation, differentiation, and apoptosis. The IGF-I actions are mediated mainly via its binding to the type I IGF receptor (IGF-IR), however IGF-I signaling via insulin receptor (IR) and hybrid IGF-I/IR is also evident. Different IGF-I mRNA splice variants, namely IGF-IEa, IGF-IEb, and IGF-IEc, are expressed in human cells and tissues. These transcripts encode several IGF-I precursor proteins which contain the same bioactive product (mature IGF-I), however, they differ by the length of their signal peptides on the amino-terminal end and the structure of the extension peptides (E-peptides) on the carboxy-terminal end. There is an increasing interest in the possible different role of the IGF-I transcripts and their respective non-(mature)IGF-I products in the regulation of distinct biological activities. Moreover, there is strong evidence of a differential expression profile of the IGF-I splice variants in normal versus PCa tissues and PCa cells, implying that the expression pattern of the various IGF-I transcripts and their respective protein products may possess different functions in cancer biology. Herein, the evidence that the IGF-IEc transcript regulates PCa growth via Ec peptide specific and IGF-IR/IR-independent signaling is discussed.

Somatostatin receptors in non-neuroendocrine malignancies: the potential role of somatostatin analogs in solid tumors

Somatostatin receptors (sstrs) are G-protein-coupled receptors that mediate various physiological effects when activated by the neuropeptide somatostatin or its synthetic analogs. In addition to the well-documented antisecretory effects of sstr2-preferential somatostatin analogs octreotide and lanreotide, ligand binding to sstr initiates an inhibitory action on tumor growth. This effect may result from both indirect actions (suppression of growth factors and growth-promoting hormones [e.g., GH/IGF-1 axis] and inhibition of angiogenesis) and direct actions (activation of antigrowth activities [e.g., apoptosis]). As solid tumor cells express multiple sstrs, there is a rationale to evaluate the potential antitumor effects of pasireotide (SOM230), a multireceptor-targeted somatostatin analog with high binding affinity for sstr1–3 and sstr5. Pasireotide reduces systemic IGF-1 levels more potently than currently available somatostatin analogs and has been well tolerated in clinical trials.

Somatostatin and somatostatin receptors: implications for neoplastic growth and cancer biology

Somatostatin agonists (SM-As) are capable of achieving durable symptomatic relief and significant clinical responses in certain tumours. Herein, we review the diverse direct and indirect mechanisms of antineoplastic activity elicited by SM-As as well as the hurdles that complicate their use as monotherapies in a broader range of malignancies. Emphasis is placed on recent clinical attempts to neutralise the IGF-mediated survival factor effects in the bone metastasis microenvironment in advanced prostate cancer. The first clinical trials of this 'anti-survival factor manipulation' strategy utilised the ability of SM-As to suppress the growth hormone-dependent liver-derived IGF-I bioavailability in combination with other drugs, such as dexamethasone, zolendronate and oestrogens, acting systemically and at the bone metastasis microenvironment. These regimens restored androgen ablation responsiveness in stage D3 prostate cancer patients and successfully produced objective clinical responses while only mild toxicities were observed. Furthermore, we focus on the preclinical experimental data of a targeted SM-A coupled to the super-potent doxorubicin derivative AN-201. The resulting conjugate (AN-238) has shown increased antitumour potency with a favourable toxicity profile. The potential use of novel SM-As as anticancer drugs is discussed in relation to data suggesting other direct and indirect treatment approaches pertaining to the somatostatin system.

Somatostatin analog lanreotide in the treatment of castration-resistant prostate cancer (CRPC)

Prostate cancer is a common disease affecting males. Despite initial sensitivity to hormone treatment, prostate cancer eventually progresses to a castration-resistant stage (CRPC), which carries an ominous prognosis. Lanreotide is a long-acting somatostatin analog with the same properties with the native peptide. It has been shown to be highly efficacious in treating various hypersecretoty disorders and tumors. Lanreotide has been administered to patients with CRPC within a novel treatment concept, with the aim of targeting not only cancer cells but also various factors secreted in the tumor cell milieu that confer protection from apoptosis. Within this concept, lanreotide has been administered as part of the "antisurvival factor therapy" in combination with dexamethasone and a gonadotropin releasing hormone (GnRH) analog. It has also been given combined with oestrogens in patients with CRPC. The so far published series have documented a clinical response in many patients treated along with significant improvement in parameters related to quality of life. In view of these promising results, large-scale, randomized, controlled trials are warranted to clearly define the exact role of lanreotide and other somatostatin analogs in the treatment of patients with CRPC.

The insulin-like growth factor-I receptor as an oncogene

The insulin-like growth factor-I receptor (IGF-IR) mediates the biological actions of both IGF-I and IGF-II. The IGF-IR is expressed in most transformed cells, where it displays potent antiapoptotic, cell-survival, and transforming activities. IGF-IR expression is a fundamental prerequisite for the acquisition of a malignant phenotype, as suggested by the finding that IGF-IR-null cells (derived from IGF-IR knock-out embryos) are unable to undergo transformation when exposed to cellular or viral oncogenes. This review article will focus on the underlying molecular mechanisms that are responsible for the normal, physiological control of IGF-IR gene expression, as well as the cellular pathways that underlie its aberrant expression in cancer. Examples from the clinics will be presented, including a description of how the IGF system is involved in breast, prostate, pediatric, and gynecological cancers. Finally, current attempts to target the IGF-IR as a therapeutic approach will be described.

Phase II trial of estramustine phosphate and oral etoposide in patients with hormone-refractory prostate cancer

BACKGROUND

There is a need for active agents with a better safety profile than docetaxel, yet good activity, for patients with hormone-refractory prostate cancer (HRPC). We carried out a phase II trial to determine the activity and safety of estramustine plus oral etoposide in HRPC.

PATIENTS AND METHODS

Patients were given estramustine (280 mg twice daily) and etoposide (100 mg/day, days 1-21) in 28-day cycles until disease progression or unacceptable toxicity. Primary end points were overall response rate and safety, as determined by prostate-specific antigen (PSA) levels and lesion assessment.

RESULTS

From November 2001 to February 2007, 75 patients were enrolled. All patients were assessable for safety; 17 (22.6%) had grade 3/4 toxicity. PSA response was assessable in 69, 14 of whom had a >50% reduction in PSA. Of 10 patients with one or more measurable lesions, two (20%) had partial response and two (20%) disease stabilization. Overall, median time to progression was 4.4 months (range 1 week-43 months); median survival was 23 months (range 3 weeks-64+ months).

CONCLUSIONS

Estramustine plus etoposide is active and has a manageable safety profile in patients with HRPC. In asymptomatic patients with nonaggressive disease this combination could be useful to delay the start of more demanding treatments.

Centromeres in cell division, evolution, nuclear organization and disease

As the spindle fiber attachment region of the chromosome, the centromere has been investigated in a variety of contexts. Here, we will review current knowledge about this unique chromosomal region and its relevance for proper cell division, speciation, and disease. Understanding the three-dimensional organization of centromeres in normal and tumor cells is just beginning to emerge. Multidisciplinary research will allow for new insights into its normal and aberrant nuclear organization and may allow for new therapeutic interventions that target events linked to centromere function and cell division.

Mechanisms of bone metastasis in prostate cancer: clinical implications

Prostate cancer shows a strong predilection to spread to the bones. Once prostate tumour cells are engrafted in the skeleton, curative therapy is no longer possible and palliative treatment becomes the only option. Herein, we review the multifactorial mechanisms and complex cellular interactions that take place inside the bone metastatic microenvironment. Emphasis is given to the detection and treatment of the micrometastatic stage of prostate cancer, as well as our recent attempts to target the bone metastasis microenvironment-related survival factors using an anti-survival factor manipulation which can increase the efficacy of anticancer therapies such as androgen ablation therapy and chemotherapy in advanced prostate cancer.

Luteinising hormone-releasing hormone antagonists in prostate cancer therapy

The introduction of androgen blockade therapy using luteinising hormone-releasing hormone (LHRH)/gonadotropin-releasing hormone analogues alone or in combination with non-steroidal antiandrogens has a major impact in both survival and quality of life of patients with locally advanced and metastatic prostate cancer. The effect of LHRH agonists is based on the continuous binding to the LHRH receptor (LHRH-R) on the gonadotrope cells of the pituitary, which although initially stimulate LH release, consequently downregulates the LHRH-R, thereby suppressing serum LH, testosterone levels and 5alpha-dihydrotestosterone levels. Because this initial surge of LH and testosterone can cause adverse consequences in these patients (the so-called flare-up symptoms), immediate inhibition of LH release and testosterone production is desirable and this can be achieved with the use of the LHRH antagonists. In addition, there exist data to support a direct anticancer effect of LHRH antagonists on prostate cancer cells. This review summarises the potential clinical use of the LHRH antagonists in prostate cancer patients.

[Hormone-refractory prostate cancer]

Hormone-refractory prostate cancer is an advanced stage of the metastatic disease; it has a poor prognosis and a short median survival, about 9 to 18 months. The current article is based on a literature review regarding the prognostic factors and medical treatments, with a focus on recent advances in chemotherapy. With the use of docetaxel that increases the median survival of this disease and improves the symptoms, new clinical protocols have been developed, with promising results; these protocols propose a combination with calcitriol or antiangiogenic agents. Supportive care is also an important part of the treatment due to the high level of bone involvement and its consequences. Such recent advances constitute a real progress in the management of prostate cancer, namely the pharmacological combinations with a promising efficacy and little toxicity.

Chemotherapy for hormone-refractory prostate cancer

BACKGROUND

Prostate cancer mainly affects elderly men, and its incidence has steadily increased over the last decade. The management of this disease is replete with controversy. In men with advanced, metastatic prostate cancer, hormone therapy is almost universally accepted as the initial treatment of choice and produces good responses in most patients. However, many patients will relapse and become resistant to further hormone manipulation; the outlook for these patients is poor. Many have disease extending to the skeleton, which is associated with severe pain. Therapies for these men include chemotherapy, bisphosphonates, palliative radiotherapy, and radioisotopes. Systemic chemotherapy has been evaluated in men with hormone-refractory prostate cancer (HRPC) for many years, with disappointing results. However, more recent studies with newer agents have shown encouraging results. There is therefore a need to explore the value of chemotherapy in this disease.

OBJECTIVES

The present review aims to assess the role of chemotherapy in men with metastatic HRPC. The major outcome was overall survival. Secondary objectives include the effect of chemotherapy on pain relief, prostate-specific antigen (PSA) response, quality of life, and treatment-related toxicity.

SEARCH STRATEGY

Trials were identified by searching electronic databases, such as MEDLINE, and handsearching of relevant journals and conference proceedings. There was no restriction of language or location.

SELECTION CRITERIA

Only published randomised trials of chemotherapy in HRPC patients were eligible for inclusion in this review. Randomised comparisons of different chemotherapeutic regimens, chemotherapy versus best standard of care or placebo, were relevant to this review. Randomised, dose-escalation studies were not included in this review.

DATA COLLECTION AND ANALYSIS

Data extraction tables were designed specifically for this review to aid data collection. Data from relevant studies were extracted and included information on trial design, participants, and outcomes. Trial quality was also assessed using a scoring system for randomisation, blinding, and description of patient withdrawal.

MAIN RESULTS

Out of 107 randomised trials of chemotherapy in advanced prostate cancer identified by the search strategy, 47 were included in this review and represented 6929 patients with HRPC. Only two trials compared the same chemotherapeutic interventions and therefore a meta-analysis was considered inappropriate. The quality of some trials was poor because of poor reporting, low-patient recruitment, or poor trial design. For clarity, trials were categorised according to the major drug used, but this was not a definitive grouping, since many trials used several agents and would be eligible for inclusion in a number of categories. Drug categories included estramustine, 5-fluorouracil, cyclophosphamide, doxorubicin, mitoxantrone, and docetaxel. Only studies using docetaxel reported a significant improvement in overall survival compared to best standard of care, although the increase was small (< 2.5 months). The mean percentage of patients achieving at least a 50% reduction in PSA compared to baseline was as follows: estramustine 48%; 5-fluorouracil 20%; doxorubicin 50% (one study only); mitoxantrone 33%; and docetaxel 52%. Pain relief was reported in 35% to 76% of patients receiving either single agents or combination regimens. A three weekly regime of docetaxel significantly improved pain relief compared to mitoxantrone plus prednisone (the latter regimen approved as standard therapy for HRPC in the USA). All chemotherapeutics, either as single agents or in combination, were associated with toxicity; the major ones being myelosuppression, gastrointestinal toxicity, cardiac toxicity, neuropathy, and alopecia. Quality of life was significantly improved with docetaxel compared to mitoxantrone plus prednisone.

AUTHORS' CONCLUSIONS

Patients with HRPC have not traditionally been offered chemotherapy as a routine treatment because of treatment-related toxicity and poor responses. Recent data from randomised studies, in particular those using docetaxel, have provided encouraging improvements in overall survival, palliation of symptoms, and improvements in quality of life. Chemotherapy should be considered as a treatment option for patients with HRPC. However, patients should make an informed decision based on the risks and benefits of chemotherapy.

Insulin-like growth factors and their binding proteins in prostate cancer: Cause or consequence?☆

Insulin-like growth factors (IGFs) promote growth and survival of many types of tumor cells. Epidemiologic studies have implicated carcinogenesis with high levels of IGFs in circulation or in tissues. The levels of IGF binding proteins (IGFBPs) have been associated with reduced risk for prostate and other cancers. Experimental studies have implicated high levels of IGF-I directly and IGFBP-3 inversely in prostate cancer growth, survival, and progression. However, recent evidence suggests a much weaker association of IGF-I with prostate cancer development and a stronger antagonistic association of IGFBP-3 with prostate cancer progression. Considering the clonal heterogeneity and unpredictable progression pattern of prostate cancer, the role of any single growth factor or its regulator (IGFBP) as a single determining factor is limited. This review is a critical appraisal of the role of IGFs, IGFBP, and IGF-I receptor (the IGF axis) in both experimental and clinical prostate cancer genesis and progression.

Combination therapy using LHRH and somatostatin analogues plus dexamethasone in androgen ablation refractory prostate cancer patients with bone involvement: a bench to bedside approach

The development of resistance to anticancer therapies is a major hurdle in preventing long-lasting clinical responses to conventional therapies in hormone-refractory prostate cancer. Herein, the molecular evidence documenting that bone metastasis microenvironment survival factors (mainly the paracrine growth hormone-independent, urokinase-type plasminogen activator-mediated increase of IGF-1 and the endocrine production of growth hormone-dependent IGF-1, mainly liver-derived IGF-1 production) produce an epigenetic form of prostate cancer cells that are resistant to proapoptotic therapies is reviewed. Consequently, the authors present the conceptual framework of a novel antibone microenvironment survival factor, mainly an anti-IGF-1 hormonal manipulation for androgen ablation refractory prostate cancer (a combination of conventional androgen ablation therapy [luteinising hormone-releasing hormone agonist-A or orchiectomy]) with dexamethasone plus somatostatin analogue, which yielded durable objective responses and major improvement of bone pain and performance status in stage D3 prostate cancer patients.

Non-hormonal systemic therapy in men with hormone-refractory prostate cancer and metastases: a systematic review from the Cancer Care Ontario Program in Evidence-based Care's Genitourinary Cancer Disease Site Group

BACKGROUND

Prostate cancer that has recurred after local therapy or disseminated distantly is usually treated with androgen deprivation therapy; however, most men will eventually experience disease progression within 12 to 20 months. New data emerging from randomized controlled trials (RCTs) of chemotherapy provided the impetus for a systematic review addressing the following question: which non-hormonal systemic therapies are most beneficial for the treatment of men with hormone-refractory prostate cancer (HRPC) and clinical evidence of metastases?

METHODS

A systematic review was performed to identify RCTs or meta-analyses examining first-line non-hormonal systemic (cytotoxic and non-cytotoxic) therapy in patients with HRPC and metastases that reported at least one of the following endpoints: overall survival, disease control, palliative response, quality of life, and toxicity. Excluded were RCTs of second-line hormonal therapies, bisphosphonates or radiopharmaceuticals, or randomized fewer than 50 patients per trial arm. MEDLINE, EMBASE, the Cochrane Library, and the conference proceedings of the American Society of Clinical Oncology were searched for relevant trials. Citations were screened for eligibility by four reviewers and discrepancies were handled by consensus.

RESULTS

Of the 80 RCTs identified, 27 met the eligibility criteria. Two recent, large trials reported improved overall survival with docetaxel-based chemotherapy compared to mitoxantrone-prednisone. Improved progression-free survival and rates of palliative and objective response were also observed. Compared with mitoxantrone, docetaxel treatment was associated with more frequent mild toxicities, similar rates of serious toxicities, and better quality of life. More frequent serious toxicities were observed when docetaxel was combined with estramustine. Three trials reported improved time-to-disease progression, palliative response, and/or quality of life with mitoxatrone plus corticosteroid compared with corticosteroid alone. Single trials reported improved disease control with estramustine-vinblastine, vinorelbine-hydrocortisone, and suramin-hydrocortisone compared to controls. Trials of non-cytotoxic agents have reported equivocal results.

CONCLUSION

Docetaxel-based chemotherapy modestly improves survival and provides palliation for men with HRPC and metastases. Other than androgen deprivation therapy, this is the only other therapy to have demonstrated improved overall survival in prostate cancer in RCTs. Further investigations to identify more effective therapies for HRPC including the use of systemic therapies earlier in the natural history of prostate cancer are warranted.

Changes in chromogranin a serum levels during endocrine therapy in metastatic prostate cancer patients

INTRODUCTION

The concept of neuroendocrine (NE) differentiation in prostate cancer has become more widely recognized as its diagnostic, prognostic, and therapeutic usefulness.

PATIENTS AND METHODS

We enrolled 38 patients with stage D prostate cancer who underwent endocrine therapy by medical or surgical castration and oral antiandrogen. According to PSA response, serum levels of CGA as a marker of NE differentiation were measured at the multiple points of time; (1) pre-treatment, (2) complete response (CR), (3) a nadir level of PSA, (4) PSA failure or hormone independent progression. We compared these serum values in relation to efficacy of endocrine therapy.

RESULTS

There was no correlation between serum PSA and CGA values. Patients consisted of 27 with CR and 11 without CR. Serum CGA increased as intervals of endocrine therapy became longer with positive correlation (p < 0.05). Its velocity was higher in patients with PSA failure than in those without it (6.98 vs. 2.09 ng/ml/month, p = 0.011).

CONCLUSION

During endocrine therapy in metastatic prostate cancer patients, serum CGA values were not related to serum PSA levels, and increased as treatment periods became longer. It is suggested that CGA velocity has potential to predict androgen independent progression after endocrine therapy.