Phase II evaluation of oral estramustine and oral etoposide in hormone-refractory adenocarcinoma of the prostate

The addition of chemotherapy in the definitive management of high risk prostate cancer

In attempt to improve long-term disease control outcomes for high-risk prostate cancer, numerous clinical trials have tested the addition of chemotherapy (CTX)-either adjuvant or neoadjuvant-to definitive local therapy, either radical prostatectomy (RP) or radiation therapy (RT). Neoadjuvant trials generally confirm safety, feasibility, and pre-RP PSA reduction, but rates of pathologic complete response are rare, and no indications for neoadjuvant CTX have been firmly established. Adjuvant regimens have included CTX alone or in combination with androgen deprivation therapy (ADT). Here we provide a review of the relevant literature, and also quantify utilization of CTX in the definitive management of localized high-risk prostate cancer by querying the National Cancer Data Base. Between 2004 and 2013, 177 patients (of 29,659 total) treated with definitive RT, and 995 (of 367,570 total) treated with RP had CTX incorporated into their treatment regimens. Low numbers of RT + CTX patients precluded further analysis of this population, but we investigated the impact of CTX on overall survival (OS) for patients treated with RP +/- CTX. Disease-free survival or biochemical-recurrence-free survival are not available through the National Cancer Data Base. Propensity-score matching was conducted as patients treated with CTX were a higher-risk group. For nonmatched groups, OS at 5-years was 89.6% for the CTX group vs. 95.6%, for the no-CTX group (P < 0.01). The difference in OS between CTX and no-CTX groups did not persist after propensity-score matching, with 5-year OS 89.6% vs. 90.9%, respectively (Hazard ratio 0.99; P = 0.88). In summary, CTX was not shown to improve OS in this retrospective study. Multimodal regimens-such as RP followed by ADT, RT, and CTX; or RT in conjunction with ADT followed by CTX-have shown promise, but long-term follow-up of randomized data is required.

Hormone Refractory Prostate Cancer (Hrpc): Present and Future Approaches of Therapy

The mainstay of therapy for patients with advanced prostate cancer still remains androgen deprivation, although response to this is invariably temporary. Most of the patients develop hormone-refractory disease resulting in progressive clinical deterioration and, ultimately, death. Until recently there has been no standard chemotherapeutic approach for hormone refractory prostate cancer (HRPC), the major benefits of chemotherapy being only palliative. The studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic HRPC with minimal toxicity and a significant palliation could be provided. Recently, results from 2 phase III randomized clinical trials demonstrating that a combination of docetaxel plus prednisone can improve survival in men with HRPC have propelled docetaxel-based therapy into the forefront of treatment options for these patients as the new standard of care. There is a promising activity of new drug combinations such as taxanes plus vinca alkaloids; bisphosphonates are assuming a prominent role in prostate therapy through their ability to prevent skeletal morbidity. Combinations of classic chemotherapeutic agents and biological drugs began to be tested in phase II-III trials and the first results appear interesting. This article focuses on combinations recently evaluated or under clinical development for the treatment of HRPC.

Randomized Comparison of Goserelin Acetate versus Mitomycin C plus Goserelin Acetate in Previously Untreated Prostate Cancer Patients with Bone Metastases

In a prospective trial conducted by the Gruppo Onco Urologico Piemontese, newly diagnosed prostate cancer patients with bone metastases were randomized to receive goserelin (3.6 mg subcutaneously every 4 weeks) or goserelin plus mitomycin at 14 mg/m2 i.v. every 6 weeks. Treatment was planned to be continued until progression. The study was interrupted because of inadequate accrual rate when 63 patients had been recruited. A long-term follow-up (median, 47 months), performed to counterbalance the limited number of patients included, revealed no difference in time to progression and overall survival between the study treatments. However, 56.5% of assessable patients allocated to the chemotherapy arm presented a ≥90% reduction of prostate-specific antigen levels compared with 36.3% in the goserelin group, and previously elevated levels normalized in 73.9% versus 45.4%. Non-progressing patients received 5-7 cycles of mitomycin C with acceptable toxicity, but the cytotoxic treatment was interrupted early in all cases within the first year due to cumulative myelotoxicity. In conclusion, the results, although inconclusive, fail to support a clear advantage in terms of cost/benefit of chemotherapy plus hormone therapy over hormone treatment alone in advanced prostate cancer with bone involvement.

Is There a Standard Chemotherapeutic Regimen for Hormone-Refractory Prostate Cancer? Present and Future Approaches in the Management of the Disease

Prostate cancer that no longer responds to hormonal manipulation can be defined as hormone-refractory prostate cancer. Until recently, there has been no standard chemotherapeutic approach for hormone-refractory prostate cancer. The major benefits of chemotherapy in the treatment of the disease are palliative in nature, in terms of reduction of pain and use of analgesics and improvement of performance status, as followed in the most recent trials. Phase III studies are necessary to better evaluate the efficacy of the different regimens, because several old studies suffer for methodological deficits. There is a promising activity of new drug combinations, such as vinca alkaloids and taxanes. Phase I and II trial are testing combinations of classic chemotherapeutic agents and biologic drugs, and the first results appear interesting. In this article, recent advances in the treatment of hormone-refractory prostate cancer using chemotherapeutic regimens are critically reviewed.

Management of Androgen-Independent Prostate Cancer

Background

Although androgen withdrawal can control prostate cancer for long periods in many patients, controversy exists regarding management when the tumor becomes androgen independent. Several options are now available.

Methods

A review of the pertinent literature of the last 20 years was conducted to provide guidance in defining and managing hormone-refractory prostate cancer.

Results

Stage D prostate cancer can be subclassified to correlate tumor biology with disease stage. Secondary hormone manipulations may induce responses in patients after failure of initial androgen suppression, and chemotherapy with docetaxel has prolonged survival in patients with androgen-independent prostate cancer (AIPC). The weight of evidence supports the maintenance of castrate levels of testosterone in metastatic AIPC. Bisphosphonates decrease skeletal complications.

Conclusions

Secondary hormone therapy, chemotherapy, and bisphosphonate therapy may provide benefits for selected patients. Correlation of disease stage with biologic characteristics of the tumor and host facilitates proper choices of interventions. Docetaxel-based chemotherapy regimens should be considered for first-line treatment of patients with progressive metastatic AIPC.

Treatment of hormone-refractory prostate cancer

Objective. An increasing number of patients with prostate cancer develop hormone-refractory disease after standard treatment modalities. In these patients, early clinical trials with chemotherapy produced disappointing response rates. However, clinical trials that employ response criteria such as prostate-specific antigen (PSA) and clinical benefit response have produced encouraging responses. This article reviews current and future treatment options for the management of hormone-refractory prostate cancer.

Data Sources. A MEDLINE search for the years 1978 to 1998 was completed. The following terms were used in our search: prostate cancer, hormone-refractory, treatment, and chemotherapy. Relevant articles referenced in the literature obtained in our MEDLINE search were reviewed.

Study Selection. Randomized and nonrandomized clinical trials were used in our review. Clinical trials using prostate-specific antigen or a palliation of symptoms as primary criteria for response were given priority.

Data Synthesis. Several genetic alterations, including the overexpression of bcl-2 or mutations in p53, may lead to the development of hormone-refractory prostate cancer. Agents such as estramustine and taxanes, which affect microtubule function and potentially modulate bcl-2, appear to be particularly active in the treatment of hormone-refractory prostate cancer. In addition, mitoxantrone as well as other agents has been shown to be beneficial in improving the quality of life in patients with hormone-refractory prostate cancer.

Conclusion. Hormone-refractory prostate cancer is not a chemotherapy-resistant disease as once believed; significant progress in the treatment of hormone-refractory prostate cancer has been made with new combinations of chemotherapy agents. Promising new treatments are currently under evaluation to assess their potential benefit over the standard treatment modalities that are currently available.

Survival analysis of patients with biochemical relapse after radical prostatectomy treated with androgen deprivation: Castration-resistance influential factors

INTRODUCTION

We evaluate the prognosis of patients with biochemical recurrence (BCR) treated with androgen deprivation therapy (ADT) and to determine the influential factors to castration resistance (CR) and death.

METHODS

From a series of 1310 patients with T1-T2 prostate cancer treated with radical prostatectomy between 1989 and 2012, 371 had BCR. Patients with lymph node involvement were excluded. We analyzed only the 159 treated with salvage ADT. At the end of the study, 77 (48%) had developed CR.

RESULTS

The median follow-up to CR was 9.2 years. The CR-resistant free survival (RFS) was 76 ± 3%, 62 ± 3% and 43 ± 9% in 5, 10 and 15 years, respectively. The RFS median time was 14 years. In the multivariate study, the prostate-specific antigen (PSA) doubling time (PSA-DT) was <6 months (p = 0.01) (hazard ratio [HR] 3; 95% confidence interval [CI] 1.4-6.8, p = 0.007); seminal vesicle involvement (HR 3.1; 95% CI 1.5-6.2, p = 0.01) and PSA velocity in ng/mL/year (HR 1.3; 95% CI 1.1-1.5, p = 0.002) with better cut-off points of 0.84 ng/mL/year (p = 0.04) (HR 4; 95% CI 1.7-9.4, p = 0.001) were influential variables. Specific survival (SS) at 5, 10 and 15 years since surgery was 96 ± 1, 85 ± 2 and 76 ± 4, respectively. The time of CR to death was 30 ± 6% at 5 years, with the median at 3.2 years. In the multivariate only Ki 67 (HR 1.04; 95% CI 1.005-1.08, p = 0.02) had an independent influence.

CONCLUSIONS

In BCR patients treated with ADT, the median to CR was 14 years. PSA-DT <6 months, PSA velocity (ng/mL/year) and seminal vesicle involvement were influential variables. From the CR, the median time to death was 3.2 years. Ki-67 marker was an independent influence.

Targeting androgen receptor action for prostate cancer treatment: does the post-receptor level provide novel opportunities?

The standard of care for patients who suffer from non-organ confined prostate cancer (CaP) is androgen deprivation therapy (ADT). ADT exploits the reliance of CaP cells on androgen receptor (AR) signaling throughout CaP progression from androgen-stimulated (AS) to castration-recurrent (CR) disease. AR is a member of the nuclear receptor family of ligand-activated transcription factors. Ligand-activated AR relocates from the cytoplasm to the nucleus, where it binds to Androgen Response Elements (AREs) to regulate transcription of target genes that control CaP cell behavior and progression. Current forms of ADT interfere at 2 levels along the AR signaling axis. At the pre-receptor level, ADT limits the availability of ligand for AR, while at the receptor level, ADT interrupts AR-ligand interactions. Both forms of ADT induce remission, but are not curative and, because of extraprostatic actions, are associated with severe side effects. Here, the potential of interference with the molecular regulation of AR-dependent transcription and the action of AR target genes, at the post receptor level, as the foundation for the development of novel, more CaP- specific selective forms of ADT is explored.

Phase II trial of oral 1,25-dihydroxyvitamin D (calcitriol) in hormone refractory prostate cancer

Epidemiologic and experimental data support a role for 1,25-dihydroxyvitamin D(3) in the growth regulation of prostate cancer. We conducted a phase II clinical trial evaluating calcitriol (1,25(OH)(2)D(3)) in patients with hormone refractory prostate cancer. We enrolled 14 patients in this study. 1,25(OH)(2)D(3) was initiated at a daily oral dose of 0.5 μg and escalated to 1.5 μg daily. No objective responses were observed. However, in two patients decreases of 25% and 45% in prostate specific antigen levels were seen. Hypercalcemia was the predominant toxicity. We conclude that 1,25(OH)(2)D(3) given in this manner is inactive in advanced prostate cancer. Dose escalation of oral 1,25(OH)(2)D(3) is limited by hypercalcemia.

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.

Gene panel model predictive of outcome in men at high-risk of systemic progression and death from prostate cancer after radical retropubic prostatectomy

PURPOSE

In men who are at high-risk of prostate cancer, progression and death from cancer after radical retropubic prostatectomy (RRP), limited prognostic information is provided by established prognostic features. The objective of this study was to develop a model predictive of outcome in this group of patients.

METHODS

Candidate genes were identified from microarray expression data from 102 laser capture microdissected prostate tissue samples. Candidates were overexpressed in tumor compared with normal prostate and more frequently in Gleason patterns 4 and 5 than in 3. A case control study of 157 high-risk patients, matched on Gleason score and stage with systemic progression or death of prostate cancer as the end point, was used to evaluate the expression of candidate genes and build a multivariate model. Tumor was collected from the highest Gleason score in paraffin-embedded blocks and the gene expression was quantified by real-time reverse transcription polymerase chain reaction. Validation of the final model was performed on a separate case-control study of 57 high-risk patients who underwent RRP.

RESULTS

A model incorporating gene expression of topoisomerase-2a, cadherin-10, the fusion status based on ERG, ETV1, and ETV4 expression, and the aneuploidy status resulted in a 0.81 area under the curve (AUC) in receiver operating characteristic statistical analysis for the identification of men with systemic progression and death from high grade prostate cancer. The AUC was 0.79 in the independent validation study.

CONCLUSION

The model can identify men with high-risk prostate cancer who may benefit from more intensive postoperative follow-up and adjuvant therapies.

Histone deacetylase inhibitors sensitize prostate cancer cells to agents that produce DNA double-strand breaks by targeting Ku70 acetylation

This study reports a histone deacetylation-independent mechanism whereby histone deacetylase (HDAC) inhibitors sensitize prostate cancer cells to DNA-damaging agents by targeting Ku70 acetylation. Ku70 represents a crucial component of the nonhomologous end joining repair machinery for DNA double-strand breaks (DSB). Our data indicate that pretreatment of prostate cancer cells with HDAC inhibitors (trichostatin A, suberoylanilide hydroxamic acid, MS-275, and OSU-HDAC42) led to increased Ku70 acetylation accompanied by reduced DNA-binding affinity without disrupting the Ku70/Ku80 heterodimer formation. As evidenced by increased Ser(139)-phosphorylated histone H2AX (gammaH2AX), impaired Ku70 function diminished cellular capability to repair DNA DSBs induced by bleomycin, doxorubicin, and etoposide, thereby enhancing their cell-killing effect. This sensitizing effect was most prominent when cells were treated with HDAC inhibitors and DNA-damaging agents sequentially. Mimicking acetylation was done by replacing K282, K317, K331, K338, K539, or K542 with glutamine via site-directed mutagenesis, which combined with computer docking analysis was used to analyze the role of these lysine residues in the interactions of Ku70 with DNA broken ends. Mutagenesis of K282, K338, K539, or K542 suppressed the activity of Ku70 to bind DNA, whereas mutagenesis of K317 or K331 with glutamine had no significant effect. Moreover, overexpression of K282Q or K338Q rendered DU-145 cells more susceptible to the effect of DNA-damaging agents on gammaH2AX formation and cell killing. Overall, the ability of HDAC inhibitors to regulate cellular ability to repair DNA damage by targeting Ku70 acetylation underlies the viability of their combination with DNA-damaging agents as a therapeutic strategy for prostate cancer.

Impact of PSA flare-up in patients with hormone-refractory prostate cancer undergoing chemotherapy

OBJECTIVES

The intention of this study is to describe the impact and underlying potential basis of the prostate-specific antigen (PSA) flare-up phenomenon in patients with hormone-refractory prostate cancer (HRPC) treated with docetaxel-based chemotherapy.

METHODS

We retrospectively identified 74 consecutive patients who received docetaxel/estramustine-based chemotherapy at our institution. Patients were evaluated based on modified criteria from the Prostate-Specific Antigen Working Group regarding survival and toxicity. Additionally, two androgen receptor mutations derived from patients with advanced disease were analyzed for promiscuous transactivation activity.

RESULTS

The 74 patients were stratified into four groups: response, partial response, flare-up-initial PSA elevation, and progression. Median survival in the flare-up group (n=8) was 20 months and did not differ from the response group (p=0.564). The flare-up group showed a maximum PSA elevation from baseline between 3.4 and 28.3% (between three and six weeks) followed by PSA decline >or=50% from the baseline level in seven of the eight patients. The androgen receptor mutations AR(877) and AR(715) displayed a 37.5- and 5.2-fold increase in transactivation activity by progesterone and a 12.6- and 5.4-fold increase by estrogen compared to the AR(WT), respectively.

CONCLUSIONS

A considerable portion of HRPC patients experience an initial PSA flare-up under systemic chemotherapy. In this study, occurrence of flare-up phenomenon did not impact survival. Chemotherapy should be continued a minimum of six weeks before removing patients from a docetaxel-based regimen. We showed evidence that co-medication with dexamethasone/prednisolone and/or estramustine itself can induce an initial PSA flare-up via androgen receptor mutations.

Phase II Evaluation of Oral Estramustine, Oral Etoposide, and Intravenous Paclitaxel in Patients with Hormone-Sensitive Prostate Adenocarcinoma

PURPOSE

The primary objective of this study was to assess the feasibility and efficacy of administering etoposide/estramustine/paclitaxel in hormone-sensitive metastatic prostate cancer responding to hormonal therapy.

PATIENTS AND METHODS

Eligible patients had metastatic prostate cancer and had received combined androgen blockade for 6-8 months with a > or = 80% decrease in prostate-specific antigen from pretreatment. They received 4 cycles of chemotherapy consisting of estramustine 280 mg orally 3 times daily, etoposide 50 mg/m2 orally on days 1-14, and paclitaxel 135 mg/m2 intravenously for 1 hour on day 2 of each 21-day cycle and were then followed until time to treatment failure (TTF).

RESULTS

Twenty-six patients were evaluable for response and toxicity. Median TTF was 21.7 months (range, 11.9-64.5 months; 95% confidence interval, 15.3-26.2 months). Median survival from time of initiation of hormone therapy was 5.1 years. Neutropenia was the most common grade 3/4 toxicity, occurring in 3 patients. Significant toxicities were limited to nausea, diarrhea, and febrile neutropenia in 3 patients, respectively.

CONCLUSION

The administration of paclitaxel/estramustine/etoposide in this setting is feasible and well tolerated. Although the TTF of 21.7 months by prostate-specific antigen criteria is similar to historical controls in the emergence of clinically evident androgen-independent disease after starting hormone therapy, direct comparisons cannot be made. More trials are needed to investigate the timing of chemotherapy in patients with prostate cancer.

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.

A randomized study of docetaxel and dexamethasone with low- or high-dose estramustine for patients with advanced hormone-refractory prostate cancer

OBJECTIVE

To test the combination of docetaxel with two different doses of estramustine in patients with hormone-refractory prostate cancer (HRPC), to improve response rates and to lower side-effects, as docetaxel-based chemotherapy is an increasing option for men with advanced HRPC, and alone or combined with estramustine, docetaxel improves median survival.

PATIENTS AND METHODS

In all, 72 patients with metastatic HRPC were randomly assigned to receive docetaxel (70 mg/m(2) intravenously, on day 2 every 21 days) and estramustine (3 x 280 mg/day oral starting 1 day before docetaxel, for 5 consecutive days) for arm A, or estramustine (3 x 140 mg/day oral starting 1 day before docetaxel, for 3 consecutive days) for arm B. Premedication with oral dexamethasone at a total daily dose of 16 mg, in divided doses twice a day was administered in arm A on day 1-5 and in arm B on day 1-3. Initially, six cycles were administered. Chemotherapy was restarted after a significant increase in prostate-specific antigen (PSA) level. Patients were monitored for any measurable PSA response and toxicity.

RESULTS

Between the arms there was no statistically significant difference in time to progression and overall survival. However, treatment B had less treatment-related toxicity than A. Independent prognostic variables were baseline factors like PSA level, haemoglobin level, Eastern Cooperative Oncology Group performance status, and bone pain at presentation.

CONCLUSIONS

In this randomized phase II study the combination of docetaxel and estramustine had substantial activity in HRPC, with a significant incidence of severe toxicity, both haematological and not. Nevertheless, treatment-related toxicity was predictable and manageable. There was no better effect with a higher dose of estramustine with docetaxel than for a lower dose. There was a slight tendency to higher toxicity for high-dose estramustine but this was not statistically significant. The present results support the assertion that estramustine is not necessary in docetaxel-based treatment regimens.

Advancing prostate cancer: treatment options for the urologist

Today's urologists often face the dilemma of how to treat patients who have advancing prostate cancer. The diversity of this patient population makes treatment decisions challenging. For over 60 years the mainstay of treatment for patients who have advancing prostate cancer has been androgen deprivation therapy. Now there are new chemotherapeutic options, novel hormone manipulations, and other adjunctive therapies available. Based on a case presentation, the authors have attempted to outline for the practicing urologist, a logical progression of treatment options for advancing prostate cancer.

Enhanced inhibitory effect of the matrix metalloproteinase inhibitor Ro 28-2653 in combination with estramustine and etoposide on the prostate carcinoma in the rat Dunning orthotopic tumor model

PURPOSE

Therapeutic efficacy of the novel matrix metalloproteinase (MMP) inhibitor Ro 28-2653 has been shown in various models of different tumor entities. We hypothesized that the inhibitor effect of Ro 28-2653 on the tumor growth could be improved by combination with chemotherapeutic drugs and examined therefore the effect of Ro 28-2653 alone and in combination with etoposide or estramustine in the MatLyLu Dunning R-3327 rat tumor model characteristic for the androgen-independent prostate cancer (PCa).

METHODS

In vitro effects were estimated measuring the proliferation of MatLyLu cells incubated with the three agents alone or in combination using the XTT test. The in vivo effects of the agents alone or in combination were examined by measuring the tumor weight 18 days after tumor cell injection.

RESULTS

The proliferation rate was only inhibited by etoposide while that effect was increased in combination with Ro 28-2653 and estramustine. Ro 28-2653 reduced the tumor weight by 86%. That effect was significantly increased in combination with etoposide to 92%.

CONCLUSIONS

The inhibitory effect of the MMP inhibitor Ro 28-2653 on the tumor growth in the Dunning PCa model is enhanced by the standard chemotherapeutic drug etoposide. A combined application of both agents could be considered as potential tool to improve the therapy of patients with advanced PCa after failure of hormonal treatment.

Changing perspectives of the role of chemotherapy in advanced prostate cancer

The use of cytotoxic chemotherapy in advanced prostate adenocarcinoma has been validated by the recent demonstration of survival benefit in two large randomized phase III trials. Before publication of these landmark trials, SWOG 9916 and TAX 327, no chemotherapeutic regimen had shown survival benefit in the treatment of androgen independent prostate cancer (AIPC). These trials provide new encouragement for the use of chemotherapy in all stages of disease. Improved communication between medical and urologic oncologists and early patient referral for clinical trial participation remains essential for identifying new chemotherapeutic regimens with improved activity in AIPC and for defining the role of chemotherapy in earlier-stage disease. This article discusses the role of chemotherapy as the current standard of care for the treatment of AIPC and provides a historical perspective of the trials that preceded the development of current docetaxel-based regimens.

Topoisomerase II-alpha expression increases with increasing Gleason score and with hormone insensitivity in prostate carcinoma

AIM

To investigate and compare topoisomerase II-alpha expression in benign prostatic hyperplasia (BPH), prostate cancer of varying Gleason scores and hormone-insensitive prostate cancer.

METHODS

The immunohistochemical expression of topoisomerase II-alpha antibody in the above-mentioned diagnostic categories was investigated and compared.

RESULTS

Increased expression of topoisomerase II-alpha was seen in the prostate cancers of Gleason scores 7 and 8-10 (p = 0.000) compared with prostate cancers of Gleason score 6 and BPH (p = 0.245). Statistically significant differences were found in the topoisomerase II-alpha gene expression between prostate cancers categorised by Gleason Score. Also, increased expression of topoisomerase II-alpha was seen in the known hormone-resistant prostate carcinomas compared with prostate cancers with no hormone treatment in the subgroup with Gleason scores 8-10, which approached statistical significance (p = 0.081). No statistically significant difference was observed in topoisomerase II-alpha expression between the groups with BPH and prostate carcinoma of Gleason score 6 (p = 0.245).

CONCLUSION

Topoisomerase II-alpha expression was found to increase with the known prognostic marker Gleason score and with hormone insensitivity. Objective evidence is provided for clinical trials with drugs targeting topoisomerase II-alpha to be targeted to patients with prostate cancers of Gleason Score >6 and, in particular, prostate cancers of Gleason Scores 8-10.

New standards in the chemotherapy of metastatic hormone-refractory prostate cancer

Hormone-refractory prostate cancer (HRPC) is a major issue in Western countries and the second leading cause of cancer death in North American men. In the prostate-specific antigen era, most HRPCs are currently diagnosed in asymptomatic patients based on biochemical failure, with increasing demand for active treatment. Until recently, chemotherapy for HRPC patients was not considered a standard of care due to the absence of clear data evidencing an overall survival benefit. In fact, few Phase III studies conducted in the 1980s and early 1990s had documented a superiority over corticosteroids alone in terms of biochemical response (declines in serum prostate-specific antigen levels) and quality of life, but not survival. Due to their impact on pain control, mitoxantrone and prednisone were long considered the best regimen for symptomatic HRPC patients. In recent years, more chemotherapeutic agents have been tested, among which the microtubule inhibitors (vinca alkaloids and taxanes) have obtained the most promising results in Phase II trials and have entered Phase III testing. Two well-designed randomized trials have changed this scenario. Both compared docetaxel (with or without estramustine) against mitoxantrone and prednisone, and demonstrated a significant advantage not only in terms of response, pain control and quality of life, but also in terms of overall survival. Which patients need to be treated, the regimen of choice and duration of chemotherapy will be the next questions to be answered in the coming years in the field of HRPC, along with the role of new signal transduction inhibitors and other targeted therapies.

Characterization of prognostic factors and efficacy in a phase-II study with docetaxel and estramustine for advanced hormone refractory prostate cancer

BACKGROUND

Docetaxel based chemotherapy not only reduces pain and improves quality of life in advanced hormone refractory prostate cancer (HRPC), but it also improves survival. We investigated the combination of docetaxel and estramustine in patients with HRPC regarding efficacy and prognostic parameters.

PATIENTS AND METHODS

We conducted a phase-II trial, administering docetaxel (70 mg/m(2) i.v., day 2, every 3 weeks) and estramustine (280 mg 3 times daily p.o., 1 day prior to docetaxel, on 5 consecutive days) to patients with HRPC. Patients were monitored for PSA (prostate-specific antigen) response and toxicity.

RESULTS

62 patients were treated. The median age was 67.5 years, the median PSA was 177.9 ng/ml. The median number of cycles was 6. The median time to progression (TTP) and median survival time were 14 (+/-2) and 24 (+/-5) months, respectively. A = 50% decrease in PSA levels from baseline occurred in 38 (61.3%) patients of whom 25 (40.3%) had a = 75% PSA decrease. The main grade 3-4 hematologic toxicities were neutropenia 34% and anemia 18%.

CONCLUSIONS

The combination of docetaxel and estramustine exerts substantial activity in HRPC suggesting an overall survival benefit with manageable toxicity. This trial also demonstrated a survival advantage for patients with early chemotherapeutic intervention. We identified PSA relapse, baseline PSA and hemoglobin as valuable prognostic factors in this setting.

Clinical trials in metastatic prostate cancer – Has there been real progress in the past decade?

Hormone refractory prostate cancer remains a challenge. While only palliative treatment strategies were available for the past several decades, many promising agents have been investigated over the past decade. Of those the taxanes appeared with significant anti-tumor activity and recently, two large randomized controlled trials demonstrated for the first time, a survival and palliative benefit with docetaxel based chemotherapy. In the current era, recurrent disease after local treatment for localized disease is diagnosed long before evidence of systemic disease. With earlier institution of hormonal treatments, patients are becoming "hormone refractory" earlier in the course of their disease with considerable long life expectancy. Hence, there is a greater need than ever for more treatment options for this expanding group of patients. A number of new systemic therapies have recently emerged, based on a deeper understanding of prostate cancer biology. Novel chemotherapeutics such as the epothilones, molecularly targeted therapies against angiogenesis, the proteosome and endothelin receptor antagonists, as well as biological agents such as anti-sense oligonucleotides are being tested as part of the armamentarium. Key to progress in the therapy of this fatal disease is the commitment and timely enrolment of prostate cancer patients in clinical trials.

High-risk localised prostate cancer: multimodal treatment strategies combining neoadjuvant hormonal therapy and/or chemotherapy with radical prostatectomy

For patients with newly diagnosed prostate cancer, clinical tumour stage, Gleason score of the diagnostic biopsy specimen and serum prostate-specific antigen (PSA) level can be combined to identify a group of men at increased risk of treatment failure after radiotherapy or radical prostatectomy. For these high-risk, but still clinically localised prostate cancers, multimodal treatment strategies may result in improved cancer control outcomes. Indeed, in the setting of clinical stage T3 - T4 tumours, the combination of radiotherapy followed by hormonal therapy has improved patient survival. The benefits of adjuvant or neoadjuvant hormonal and/or chemotherapy followed by radical prostatectomy in this setting are unclear, but are the subject of ongoing or planned Phase III clinical trials. These studies will help define the role of multimodal treatment strategies in this high-risk patient population.

A phase II study of vinorelbine and estramustine in patients with hormone-resistant prostate cancer

INTRODUCTION

This phase II study was designed to evaluate the efficacy of vinorelbine in combination with estramustine in patients with chemotherapy-naïve hormone-refractory prostate cancer.

MATERIAL AND METHODS

Patients received vinorelbine (i.v. 25 mg/m2) on days 1 and 8 every 3 weeks and estramustine (oral, 600 mg/m2) daily. Eligible patients were required to have progressive metastatic disease following the first hormonal manipulation.

RESULTS

Of the 51 patients enrolled (median age = 69 years), 84% presented bone involvement and 75% had at least two organs involved at the time of study entry and 47 were evaluable for treatment efficacy. Prostate specific antigen (PSA) response (> or =50% decrease) which was the primary efficacy criterion was reported in 21 patients (41.2%) in the intent-to-treat (ITT) population and in 20 patients (48.8%) in the per protocol (PP) population. Of the 7 patients with measurable disease, 2 achieved partial response. Median progression-free survival and overall survival were 4.7 months (range: 1.9-8.6) and 14.3 months (range: 4.2-21.2), respectively. Grade 3-4 neutropenia was reported in 6.1% of patients and in 1% of cycles. The incidence of complicated neutropenia (febrile neutropenia reported in 1 patient and septic shock with severe neutropenia reported in 2 patients) was 5.8%. The most frequent grade 3-4 non-haematological events (% of patients > or =5%) included anorexia (10%), thrombosis/embolism (8%), vomiting and hypotension (6% each). There were 3 toxic deaths (5.9 %) resulting from pulmonary embolism, angina pectoris, and septic shock. The impact of combined chemotherapy on the quality-of-life (QL) of the patients was assessed between baseline and the first evaluation scheduled at 6 weeks indicated a marked reduction in pain while the rest of the symptoms remained stable. Overall, health status improved slightly over the treatment period.

CONCLUSIONS

This study confirmed that the combination of vinorelbine and estramustine is an active regimen in patients with hormone-resistant prostate cancer who had not been treated previously with chemotherapy. Main toxicities included complicated neutropenia even though the incidence of severe neutropenia was low. We observed a higher incidence of toxic deaths which could have been related to the regimen of estramustine used in the study.

Sequential mitoxantrone/prednisone followed by docetaxel/estramustine in patients with hormone refractory metastatic prostate cancer: results of a phase II study

BACKGROUND

Mitoxantrone/prednisone ameliorates symptoms in hormone refractory prostate cancer (HRPC) but has no effect on survival. Docetaxel (Taxotere)/estramustine improves response but with significant toxicity. We reasoned that a sequential administration of the two regimens could be a viable alternative for delivering full doses of chemotherapy, avoiding overlapping toxicity and preserving dose intensity.

PATIENTS AND METHODS

Thirty HRPC patients were treated with mitoxantrone 10 mg/m(2), day 1, every 3 weeks, plus prednisone 5 mg twice daily, for three cycles, followed by estramustine phosphate, 280 mg three times daily, days 1 to 5, plus docetaxel 75 mg/m(2), day 2, every 3 weeks for a maximum of 10 cycles.

RESULTS

All patients were assessable for response and toxicity. After mitoxantrone/prednisone treatment, the prostate-specific antigen (PSA) response rate was 23%, which increased to 63% after completion of sequential mitoxantrone/prednisone and docetaxel/estramustine treatment (12 partial and 7 complete responses). With a median follow-up of 18 months, median survival for all patients was 18 months, and median progression-free survival was 10 months. The mitoxantrone/prednisone regimen was well tolerated, and the only grade 3-4 toxicity was grade 3 neutropenia in four (13%) patients. Twenty-nine patients received a total of 173 cycles of docetaxel/estramustine (median, 6 cycles/patient). Six (20%) patients had grade 3-4 neutropenia and two (6%) patients had febrile neutropenia episodes. The most frequent non-hematological toxic effects were asthenia, nausea and vomiting, edemas and onycholysis. Two (6%) patients had deep venous thrombosis.

CONCLUSIONS

Mitoxantrone/prednisone followed by docetaxel/estramustine is a well-tolerated and active regimen in HRPC. Sequential therapy is feasible and can be used to integrate novel, more active regimens.

Oral estramustine plus oral etoposide in the treatment of hormone refractory prostate cancer patients: A phase II study with a 5-year follow-up

BACKGROUND

Chemotherapy regimens that target microtubular trafficking were repeatedly found to be active in the treatment of hormone refractory prostate cancer patients, but disease responses were reportedly short-lived on average.

MATERIALS AND METHODS

From 1994 to 1997, 46 consecutive patients with hormone refractory prostate cancer were enrolled in a multicenter Phase II trial of oral etoposide 100 mg/day and estramustine 560 mg/day for 21 days, followed by a 7-day rest period. Final evaluation of this trial was performed after a follow-up of 5 years.

RESULTS

Fifty-four percent of patients attained a PSA response and 46% attained a response on measurable lesions. Median time to progression (TTP) and overall survival were 7.4 and 18.4 months, respectively. Fourteen patients (30.4%) had a TTP greater than 12 months and 9 (19.5%) a TTP greater than 18 months. Sixteen patients (34.8.%) survived more than 2 years and 2 (4.3%) survived more than 5 years. One patient was still alive and free from progression more than 7 years after starting treatment.

CONCLUSIONS

This Phase II trial with a long-term follow-up revealed that some patients with hormone refractory prostate cancer could obtain durable disease response and long survival with an oral etoposide and estramustine combination regimen.

Thromboembolic events with estramustine phosphate-based chemotherapy in patients with hormone-refractory prostate carcinoma: results of a meta-analysis

BACKGROUND

Combinations of cytotoxic chemotherapy with estramustine phosphate (EMP), a nornitrogen mustard-estrogen conjugate, are used to treat patients with hormone-refractory prostate carcinoma (HRPC). However, thromboembolic events (TE), including deep venous thrombosis (DVT), pulmonary embolism, stroke, myocardial infarction, and arterial thrombosis, are significant toxicities of these regimens. The current study sought to establish the rate of TE and to determine risk factors for TE.

METHODS

A MEDLINE-based search identified EMP-based clinical trials published in the English-language peer-reviewed literature after 1990 in which > or = 20 patients with HRPC were enrolled and TE were clearly documented. Patient characteristics and the dose of EMP given were analyzed to determine their association with the rate of TE.

RESULTS

Twenty-three studies, enrolling a total of 896 patients, were included in the analysis. The overall risk of TE was 0.07 (95% confidence interval [95% CI], 0.05-0.11). The risk of DVT was 0.06 (95% CI, 0.04-0.09). The risks of all other types of TE were <0.01. Using univariate logistic regression analysis, the dose of EMP administered, baseline patient age, and baseline prostate-specific antigen level were not found to be associated with the total risk of TE. The rates of total TE and DVT may be inflated because one of the analyzed studies initially had a very high rate of DVT (25%) when compared with the others.

CONCLUSIONS

The rate of TE in men with HRPC who are treated with EMP-based regimens is significant, but it does not appear to be related to the dose of EMP. Whether TE can be prevented with anticoagulant prophylaxis remains to be determined.

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

OBJECTIVES

To evaluate prospectively the combination of a luteinizing hormone-releasing hormone analog with a somatostatin analog and dexamethasone in patients with hormone-refractory prostate cancer (HRPC) in a randomized Phase II study. HRPC presents a challenging therapeutic problem. Salvage chemotherapy is the usual approach at this stage of the disease. The combination of a luteinizing hormone-releasing hormone analog with a somatostatin analog and dexamethasone has produced objective clinical responses in HRPC.

METHODS

Forty patients with HRPC were randomized to receive one of two treatments. Group 1 underwent chemotherapy (estramustine 140 mg three times daily and etoposide 100 mg orally for 21 days) and group 2 the combination of a somatostatin analog (lanreotide 30 mg intramuscularly every 14 days) and dexamethasone (4 mg tapered to 1 mg), in addition to androgen ablation by orchiectomy or a luteinizing hormone-releasing hormone analog (triptorelin 3.75 mg intramuscularly every 28 days). The clinical and prostate-specific antigen (PSA) response, overall survival, time to progression, and toxicity were compared between the two groups.

RESULTS

The data of 20 patients in group 1 and 18 in group 2 were analyzed. The demographic and clinical data were similar in the two groups at study entry. A PSA response (decrease of greater than 50%) was observed in 45% of group 1 and 44% of group 2. The difference was not statistically significant. A partial clinical response was observed in 29% and 30% of groups 1 and 2, respectively. Again, the difference was not statistically significant. Changes in performance status and pain score during treatment were not significantly different in the two groups. Hematologic toxicity was more frequent in group 1 (80% of patients), and mild diabetes was more frequent in group 2 (22% of patients). The overall survival was 18.8 months in group 1 and 18 months in group 2 (not statistically significant). The time to progression was 6 versus 4 months and, in the PSA responder subgroup, it was 8 versus 7.7 months in groups 1 and 2, respectively (neither difference was statistically significant).

CONCLUSIONS

The results of our randomized Phase II study indicated that the new combination treatment (luteinizing hormone-releasing hormone analog, somatostatin analog, and dexamethasone) may be equally effective as salvage chemotherapy in patients with HRPC in terms of the clinical and PSA response, overall survival, and time to progression. A larger prospective Phase III trial is required to confirm our observations.

Prevention and management of prostate cancer chemotherapy complications

Prevention and management of the adverse effects of prostate cancer chemotherapy depend on skilled regimen selection, dose adjustment, use of supportive care strategies, and a thorough understanding of the patient- and regimen-related factors that determine the risk for toxicity. Urologists, radiation oncologists, and primary care providers can play an important role before chemotherapy is prescribed by judicious use of treatments that impair bone marrow and other vital organ function. The current role of chemotherapy in prostate cancer is palliative. Successful palliation depends on reducing cancer-related suffering without introducing treatment-related suffering. Thus prevention and management of toxicity is central to the success of chemotherapy in advanced prostate cancer.

[Taxanes in the chemotherapy of hormone-refractory prostate carcinoma]

Prostate cancer represents one of the most prevalent malignancies in men. Standard therapy of metastatic prostate cancer consists of androgen deprivation, which is a palliative therapy yielding a clinical response of limited duration. In hormone-refractory prostate cancer (HRPC), response to chemotherapy with regimens available until about ten years ago has been disappointing. Nowadays, due to increasing life expectancy and earlier diagnosis and therapy of prostate cancer, more patients with hormone-refractory disease are still in relatively good overall condition. With the taxanes, much more effective cytostatic substances for chemotherapy of HRPC are available today. Using modern taxane-based chemotherapy, effective palliation of pain can be achieved in 50-70% of patients with HRPC, while retaining an acceptable quality of life. There is also evidence for improved overall survival after taxane-based chemotherapy, although this remains to be proven by ongoing studies. This article presents an overview of current studies investigating the outcome after taxane-based chemotherapy, as well as new therapeutic approaches in combination with docetaxel.

Development of prostate cancer treatment: the good news

Prostate cancer is the most commonly diagnosed cancer in American men representing one-third of all new cancer cases each year. This translates into one out of every six American men being diagnosed with prostate cancer over the course of their lifetimes. Over 31,000 of these men die each year from prostate cancer. Before the 1980's, 50% of men were diagnosed with widespread metastatic disease and there were few therapeutic choices for patients. The good news for patients is that, over the last 30 years there have been significant advances in detection and prognostication as well as major improvements in the surgical, radiation, and medical oncological management of prostate cancer. This review describes the evolution of these therapeutic modalities for prostate cancer. This evolution has been driven by the explosion of knowledge concerning cancer in general and in the specific biology of prostate cancer in particular over the last 30 years. This knowledge has been obtained by concentrating human and financial resources in organ specific studies of the prostate. The end result of this effort is that, today, 85% of new prostate cancer cases are diagnosed at local and regional stages and the 5-year relative prostate cancer survival rate has increased by 20% since 1985. In addition, the therapeutic approach to prostate cancer can now be individualized based on the characteristics of the patient's disease. Finally, recent data suggest that the death rate from prostate cancer is decreasing by approximately 4% per year since 1994. Further good news for patients is that new discoveries about the biology of prostate cancer are rapidly being translated into new therapies, a large number of which are currently being tested in clinical trials. Continued allocation of appropriate human and material resources should yield new, more effective therapies for prostate cancer that will further impact patient quality of life and survival in the 21st century.

Society of Urologic Oncology position statement: Redefining the management of hormone-refractory prostate carcinoma

Because patients with hormone-refractory prostate carcinoma are a very diverse group, management of these patients represents a unique challenge. Despite much research, to the authors' knowledge few studies published to date have provided definitive treatment answers. The Society of Urologic Oncology (SUO) convened a multidisciplinary panel of urologists, oncologists, and radiation oncologists to develop a treatment algorithm for patients with hormone-refractory prostate carcinoma. The resulting treatment outline was based on a review of the literature review and on the expert opinions of the panelists. The current article provided a logical progression of treatment choices that included hormonal manipulations, chemotherapeutic options, and adjunctive therapies. Future clinical trials and therapies were also discussed by the authors. Management strategies should be targeted toward the individual patient. Although significant progress has been made in understanding and treating hormone-refractory prostate carcinoma, earlier interventions would be ideal and better therapeutic approaches to prolong survival are necessary.

Cancer and Leukemia Group B (CALGB) 90203: a randomized phase 3 study of radical prostatectomy alone versus estramustine and docetaxel before radical prostatectomy for patients with high-risk localized disease

The purpose of The Cancer and Leukemia Group B (CALGB) 90203 trial is to determine which of 2 treatment strategies is superior in treating men with high-risk, clinically localized adenocarcinoma of the prostate (stage T1 to T3a NX M0), defined as a predicted probability < or =60% of remaining free from disease recurrence for 5 years after surgery. Patients with a > or =10-year life expectancy will be randomized to either radical prostatectomy (RP) alone versus estramustine and docetaxel before RP. Participants will be excluded if they have received prior therapy for prostate cancer (except transurethral resection of the prostate) or are judged not to be appropriate candidates for RP. Eligible patients will be stratified according to their predicted probability of remaining free from disease recurrence at 5 years after surgery (0% to 20%, 21% to 40%, and 41% to 60%) and randomized. Neoadjuvant chemotherapy will be 6 cycles (1 cycle = 21 days) of estramustine (280 mg tid, days 1 to 5) and docetaxel (70 mg/m2 on day 2). Warfarin (2 mg/day orally) will be given for prophylaxis against deep venous thrombosis. Bilateral pelvic lymph node dissection and RP will be performed within 60 days of registration/randomization for men randomized to the surgery-alone arm. For men randomized to receive preoperative chemotherapy, the surgical procedure will be performed within 60 days of completion of chemotherapy. Patients will be monitored with history review, physical examination, and serum prostate-specific antigen (PSA) levels every 3 months for the first 3 years after surgery, every 6 months for the next 3 years, and annually thereafter. Biochemical disease recurrence will be defined as a serum PSA level >0.4 ng/mL on 2 consecutive occasions > or =3 months apart after RP. The time of biochemical failure is measured from the date of randomization to the time of the first PSA level <0.4 ng/mL that is confirmed on the second serial PSA. The primary study end point is to determine if early systemic treatment with neoadjuvant estramustine and docetaxel before RP in patients with high-risk prostate cancer will decrease 5-year recurrence rates when compared with RP alone. Secondary outcomes will include (1) the safety and tolerability of neoadjuvant estramustine and docetaxel before RP; (2) the impact of this neoadjuvant strategy on pathologic tumor stage, including lymph node and surgical margin status; (3) time to clinically apparent disease recurrence; and (4) overall survival. The impact of RP with and without neoadjuvant estramustine and docetaxel on the patient's quality of life from pretreatment through year 3 will be assessed. Frozen prostate tissue will be obtained from men undergoing prostatectomy who are enrolled in either the treatment or control arms of the trial. These samples will be analyzed for their RNA expression patterns in order to build outcome prediction models. Furthermore, using array-based methods of expression analysis, the sensitivity to chemotherapeutic agents and response to chemotherapy may likewise be predicted. The trial will enroll approximately 700 men during a 48-month period. Patients will be observed for 84 months after study closure. The power to detect a 36% decrease in 5-year recurrence rates is 90%.

Radiation Therapy Oncology Group P-0014: a phase 3 randomized study of patients with high-risk hormone-naive prostate cancer: androgen blockade with 4 cycles of immediate chemotherapy versus androgen blockade with delayed chemotherapy

Currently, approximately 30,000 men die annually of metastatic, hormone-refractory prostate cancer. Androgen blockade is palliative and is generally effective for an average of 2 to 3 years until a patient develops androgen-independent disease. Newer chemotherapeutic regimens can induce remissions in approximately 50% of patients; however, median survival for patients with androgen-independent disease is still 8 to 12 months. The strategy of using chemotherapy regimens after androgen blockade has been proved noncurative, and new approaches are needed to attempt to cure patients with advanced disease. It has been demonstrated in the preclinical setting that androgen withdrawal induces apoptosis in cancer cells in both the Shinogi breast cancer model and the LNCaP prostate cancer model. In both of these models, androgen withdrawal was not curative, and the tumors grew back in a hormone-independent state. It is possible that the addition of chemotherapy at the time of initial androgen ablation will improve cell kill by potentiating apoptosis, thereby killing cells that might otherwise have mutated to the androgen-independent state if allowed to continue to cycle and grow. The rationale behind Radiation Therapy Oncology Group (RTOG) P-0014 is to demonstrate in a randomized phase 3 trial that giving patients chemotherapy at the beginning of androgen blockade may improve patient survival.

Weekly paclitaxel, estramustine phosphate, and oral etoposide in the treatment of hormone-refractory prostate carcinoma

BACKGROUND

The objective of the current study was to evaluate the efficacy and toxicity of weekly paclitaxel, oral etoposide, and estramustine phosphate in the treatment of patients with advanced, hormone-refractory prostate carcinoma.

METHODS

Patients with hormone-refractory prostate carcinoma who had received no more than one previous chemotherapy regimen were eligible for this trial. Forty-two patients were treated between February 1998 and March 2000. Toxicity was excessive in the first 3 patients treated (Grade 3-4 leukopenia, 3 patients; death due to sepsis, 1 patient); the remaining 39 patients received lower doses of etoposide and estramustine phosphate (paclitaxel 50 mg/m(2) as a 1-hour, intravenous infusion on Days 1, 8, 15; etoposide 50 mg orally twice daily on Days 1-10; and estramustine phosphate 280 mg orally 3 times daily on Days 1-10). Courses were repeated every 28 days. Patients were evaluated for objective and/or serologic response after two courses of treatment; responding patients continued treatment for six courses.

RESULTS

Fourteen of 40 evaluable patients (35%) had either an objective response or a serologic response to treatment. The median survival for the entire group was 9.5 months, with 1-year, 2-year, and 3-year survival rates of 38%, 12%, and 10%, respectively. Neutropenia was the most common Grade 3-4 toxicity and occurred in 38% of patients (11% of courses). Thirteen patients (33%) had severe fatigue, and 2 patients had treatment-related deaths due to sepsis.

CONCLUSIONS

Although the three-drug combination had activity in patients with hormone-refractory prostate carcinoma, the results did not appear any better than the results achieved with less toxic taxane/estramustine phosphate combinations. Further development of this three-drug regimen is not recommended.

Foundation for the integration of biologically based therapy in the management of prostate cancer

The cure of advanced prostate cancer (PCa) will be achieved through the clinical application of biological observations. To achieve this, a new classification of human PCa is needed. Unlike in previous classifications of PCa which were based on anatomic determinates of outcome, we propose to integrate emerging PCa biology into this taxonomy. Three biologically based categories were identified (amphotropic, clonal expansion, and heterotopic), and each has unique features that influence therapy selection. It is unlikely that any single agent or modality will successfully control PCa. It is hoped that the classification and trial designs we propose will facilitate the application of integrated treatment and prevention strategies.

Phase II study of oxaliplatin versus oxaliplatin combined with infusional 5-fluorouracil in hormone refractory metastatic prostate cancer patients

BACKGROUND

A randomized, multicenter phase II study evaluating oxaliplatin alone (OXA) and oxaliplatin-5-fluorouracil combination (OXFU) in advanced hormone-refractory prostate cancer (HRPC) patients.

PATIENTS AND METHODS

Metastatic, pathologically proven prostate carcinoma patients, progressing despite anti-androgen therapy, received intravenous OXA (130 mg/m(2 )over 2 h), alone or with 5-FU (1000 mg/m(2)/day, continuous intravenous infusion, days 1-4), every 3 weeks. OXA patients could receive OXFU after treatment failure.

RESULTS

Fifty-four patients (26 OXA, 28 OXFU) from nine centers received 269 treatment cycles (106 OXA, 163 OXFU; median 3.5 OXA or 5 OXFU cycles per patient; range 1-10 or 1-14, respectively). Patient characteristics were similar in both arms. Three partial responses (PR) occurred in 21 evaluable OXA patients [14%; 95% confidence interval (CI) 1% to 30%], and in five of 26 evaluable OXFU patients (19%; 95% CI 7% to 39%). Clinical benefit response (pain, performance status and weight changes) was assessed in 20 OXA and 22 OXFU symptomatic patients, with more responders in the OXFU arm (39% compared with 12%). Median time to progression in the OXA and OXFU arms was 2.6 and 3.4 months, and median overall survival was 9.4 and 11.4 months, respectively. Hematotoxicity was common, but mostly mild to moderate. Neutropenia was more common in OXFU than OXA patients. After oxaliplatin failure, 12 patients received 46 cycles of OXFU and one of 11 evaluable patients had a PR.

CONCLUSION

The objective response rate, palliation benefit, survival and manageable toxicity obtained in this heavily pretreated HRPC population with OXFU merit further study.

Phase II trial of paclitaxel, estramustine, etoposide, and carboplatin in the treatment of patients with hormone-refractory prostate carcinoma

BACKGROUND

Preclinical data suggest that the combination of intravenous (i.v.) paclitaxel, carboplatin, oral etoposide, and oral estramustine (TEEC) has significant activity in patients with advanced, hormone-refractory prostate carcinoma. The authors conducted this clinical trial to evaluate the addition of carboplatin to the three-drug combination of paclitaxel, estramustine, and etoposide (TEE).

METHODS

Twenty patients with carcinoma of the prostate that was progressing despite hormone therapy were enrolled on this Phase II trial. Patients were treated with oral estramustine, 280 mg three times daily, and oral etoposide, 50 mg/m2, once daily on Days 1-7, with i.v. paclitaxel, 135 mg/m2, over 1 hour followed by carboplatin (area under the curve, 5) on Day 2 of each 21-day treatment cycle. Patients were evaluated for response after three cycles, and three additional cycles were given to responding or stable patients.

RESULTS

Nineteen patients were evaluable for response, and 12 patients had measurable disease at baseline. The measurable response rate was 58% (7 of 12 patients; 95% confidence interval [95% CI], 28-85%), and all of those were partial responses. Eleven patients had decreases >50% from their baseline prostate specific antigen levels during therapy, for a response rate of 58% (95% CI, 34-80%) by this criterion. The median time to disease progression was 5.5 months, with a median survival of 14.2 months. Major toxicities included Grade (according to version 2 of the National Cancer Institute Common Toxicity Criteria) 4 neutropenia in 4 patients, Grade 4 thrombocytopenia in 4 patients, and anemia > or = Grade 3 in 4 patients. One patient had a deep vein thrombosis.

CONCLUSIONS

The combination of TEEC was active in patients with hormone-refractory prostate carcinoma. The regimen was tolerable, with primarily hematologic toxicity. The addition of carboplatin to TEE did not appear to add to the efficacy of the three-drug combination of antimicrotubule agents.

Optimizing targeted therapy and developing novel outcome measures for patients with advanced prostate cancer at Memorial Sloan-Kettering Cancer Center

Hormonal therapy and chemotherapy, though active treatments for prostate cancer, are not curative for patients with metastatic disease. Targeted therapy has the potential to control, if not eradicate, cells resistant to castration and chemotherapy. Despite several years of development, however, a biologic approach with clear clinical benefits has yet to emerge from a crowded field. This review outlines the approaches being studied at Memorial Sloan-Kettering Cancer Center to optimize biologic therapy. Trials of targeted therapy are designed on the basis of a clinical states model that describes both patient clinical risks and tumor biology. Drugs that act on multiple pathways are being developed, and targets that are expressed across all phases of the disease are selected. New molecular imaging techniques permit assessments of the target before, during, and after treatment. High-throughput preclinical assays of gene expression are being developed to enhance selection of drug sequences and combinations for clinical testing.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.

Pharmacotherapy of hormone refractory prostate cancer: new developments and challenges

Hormone refractory prostate cancer (HRPC) remains a challenge in the management of prostate cancer patients. With the widespread use of PSA (prostate specific antigen), recurrent disease after local treatment for localised prostate cancer is usually diagnosed long before evidence of metastatic disease. In many cases, hormonal manipulations are started at the time of biochemical relapse and therefore, patients become 'hormone refractory' earlier in the course of their disease, frequently with a good performance status, often with no evidence of metastatic disease, and they still face a considerably long life expectancy. Despite these changes, the need for more options in the treatment of HRPC is obvious. The pharmacological treatments that are in use and those that are under investigation for this group of patients will be discussed and include: cytotoxic agents including the microtubule inhibitors, alone and in combination with other conventional or experimental therapies such as calcitriol or thalidomide; treatment with epothilone analogues; endothelin receptor antagonists; palliative therapy with bisphosphonates, bone-targeted radiopharmaceuticals and other developing treatments such as vaccines, gene therapies and monoclonal antibodies.

Prognostic model for predicting survival in men with hormone-refractory metastatic prostate cancer

PURPOSE

To develop and validate a model that can be used to predict the overall survival probability among metastatic hormone-refractory prostate cancer patients (HRPC).

PATIENTS AND METHODS

Data from six Cancer and Leukemia Group B protocols that enrolled 1,101 patients with metastatic hormone-refractory adenocarcinoma of the prostate during the study period from 1991 to 2001 were pooled. The proportional hazards model was used to develop a multivariable model on the basis of pretreatment factors and to construct a prognostic model. The area under the receiver operating characteristic curve (ROC) was calculated as a measure of predictive discrimination. Calibration of the model predictions was assessed by comparing the predicted probability with the actual survival probability. An independent data set was used to validate the fitted model.

RESULTS

The final model included the following factors: lactate dehydrogenase, prostate-specific antigen, alkaline phosphatase, Gleason sum, Eastern Cooperative Oncology Group performance status, hemoglobin, and the presence of visceral disease. The area under the ROC curve was 0.68. Patients were classified into one of four risk groups. We observed a good agreement between the observed and predicted survival probabilities for the four risk groups. The observed median survival durations were 7.5 (95% confidence interval [CI], 6.2 to 10.9), 13.4 (95% CI, 9.7 to 26.3), 18.9 (95% CI, 16.2 to 26.3), and 27.2 (95% CI, 21.9 to 42.8) months for the first, second, third, and fourth risk groups, respectively. The corresponding median predicted survival times were 8.8, 13.4, 17.4, and 22.80 for the four risk groups.

CONCLUSION

This model could be used to predict individual survival probabilities and to stratify metastatic HRPC patients in randomized phase III trials.