A comparison of estramustine phosphate versus cis-platinum alone versus estramustine phosphate plus cis-platinum in patients with advanced hormone refractory prostate cancer who had had extensive irradiation to the pelvis or lumbosacral area

Role of chemotherapy in prostate cancer

Chemotherapy in prostate cancer (PCa) has undergone dramatic landscape changes. While earlier studies utilized varying chemotherapy regimens which were found to be largely palliative in nature and hardly resulted in durable or meaningful responses, docetaxel resulted in the first chemotherapy agent that showed improvement in overall survival in metastatic castration-resistant prostate cancer (mCRPC). However, combination chemotherapy or any agents added to docetaxel have failed to yield incremental benefits. The improvement in overall survival as well as secondary endpoints of prostate-specific antigen (PSA) and time to recurrence when using docetaxel in the metastatic hormone-sensitive state has changed the standard of care for treatment of newly diagnosed de novo metastatic PCa. There are also promising results in locally advanced PCa and high-risk PCa in both the neoadjuvant and adjuvant settings. This review summarizes the historical as well as the more contemporary use of chemotherapeutic agents in PCa in varying states and phases of disease.

Anti-tumour activity of platinum compounds in advanced prostate cancer-a systematic literature review

BACKGROUND

For men with advanced castration-resistant prostate cancer (CRPC), several treatment options are available, including androgen receptor (AR) pathway inhibitors (abiraterone acetate, enzalutamide), taxanes (docetaxel, cabazitaxel) and the radionuclide (radium-223). However, cross-resistance is a clinically relevant problem. Platinum compounds have been tested in a number of clinical trials in molecularly unselected prostate cancer patients. Advances in CRPC molecular profiling have shown that a significant proportion of patients harbour DNA repair defects, which may serve as predictive markers for sensitivity to platinum agents.

OBJECTIVE

To systematically identify and analyse clinical trials that have evaluated platinum agents in advanced prostate cancer patients.

METHODS

PubMed was searched to identify published clinical trials of platinum agents in advanced prostate cancer. The PRIMSA statement was followed for the systematic review process. Identified trials are analysed for study design, statistical plan, assessments of anti-tumour activity and the potential value of predictive biomarkers.

RESULTS

A total of 163 references were identified by the literature search and 72 publications that met the selection criteria were included in this review; of these 33 used carboplatin, 27 cisplatin, 6 satraplatin, 4 oxaliplatin and 2 other platinum compounds. Overall, anti-tumour activity varies in the range of 10%-40% for objective response and 20%-70% for PSA decline ≥50%. Response seemed highest for the combinations of carboplatin with taxanes or oxaliplatin with gemcitabine. The interpretation of the clinical data is limited by differences in response criteria used and patient populations studied.

CONCLUSION

Platinum compounds have moderate anti-tumour activity in molecularly unselected patients with advanced prostate cancer. Translational evidence of DNA repair deficiency should be leveraged in future studies to select prostate cancer patients most likely to benefit from platinum-based therapy.

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.

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist's armamentarium.

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.

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.

Prospective Study of Estramustine Phosphate for Hormone Refractory Prostate Cancer Patients following Androgen Deprivation Therapy

INTRODUCTION

Estramustine phosphate (EMP) in combination with other cytotoxic agents has been widely used in clinical trials as an anti-tumor agent for the treatment of hormone-refractory prostate cancer (HRPC). However, few prospective studies have considered the efficacy of EMP monotherapy for HRPC patients following androgen-deprivation therapy (ADT), given the availability of methods to measure prostate-specific antigen (PSA) levels in the serum. We therefore initiated a prospective study to determine whether EMP is efficient for HRPC following ADT using changes in PSA levels as the major endpoint.

METHODS

After a diagnosis of anti-androgen withdrawal syndrome had been excluded, 34 patients with HRPC who showed an elevated serum PSA level in 3 or more sequential tests following ADT were treated orally with 560 mg/day of EMP. The clinical stage and the median PSA value for inclusion in the study were D2 and 25.9 (range 6.5-540.8) ng/ml, respectively. Treatment was continued until evidence of disease progression reappeared or until severe adverse effects appeared.

RESULTS

Of the 34 patients enrolled, 29 were evaluated, while the other 5 (15%) patients were discontinued due to severe gastrointestinal side effects. Seven of the 29 patients (24%) showed a decrease of 50% or greater in serum PSA levels from the initially elevated values, with the median duration of PSA response being 8.0 (range 2.2-18.8) months. Baseline PSA, hemoglobin, alkaline phosphatase, lactate dehydrogenase, performance status, and length of time of initial hormonal treatment did not correlate with the PSA response. With a median follow-up time of 20.0 (range 3.2-45.6) months, the cancer-specific survival rate at 2 years was 83% in the PSA responders and 44% in the non-responders. The PSA response was correlated with cancer-specific survival (p = 0.029).

CONCLUSIONS

Following ADT one quarter of HRPC patients responded to EMP, with more than 50% of patients showing a decrease in PSA levels and an enhanced survival rate.

Phase III trial of satraplatin, an oral platinum plus prednisone vs. prednisone alone in patients with hormone-refractory prostate cancer

Satraplatin is a novel oral platinum (IV) complex that shows activity against hormone-refractory prostate cancer (HRPC) in cisplatin-resistant human tumor lines in phase I and phase II trials. A randomized multicenter phase III trial with a target sample size of 380 patients was initiated in men with HRPC. After 50 randomized patients, the trial was closed to further accrual by the sponsoring company. An ad hoc analysis of all available data is reported here. Eligibility criteria included pathological proof of prostate cancer, documented progression despite prior hormonal manipulation, WHO PS 0-2, and no daily intake of narcotic analgesics. Patients were randomized between satraplatin 100 mg/m(2) for 5 days plus prednisone 10 mg orally BID or prednisone alone. Compliance was excellent. 48/50 patients have progressed and 42 have died, mostly due to prostate cancer. Median overall survival was 14.9 months (95% CI: 13.7-28.4) on the satraplatin plus prednisone arm and 11.9 months (95% CI: 8.4-23.1) on prednisone alone (hazard ratio, HR = 0.84, 95% CI: 0.46-1.55). A >50% decrease in prostrate specific antigen (PSA) was seen in 9/27 (33.3%) in the satraplatin plus prednisone arm vs. 2/23 (8.7%) on the prednisone alone arm. Progression-free survival was 5.2 months (95% CI: 2.8-13.7) on the satraplatin plus prednisone arm as compared to 2.5 months (95% CI: 2.1- 4.7) on the prednisone alone arm (HR = 0.50, 95% CI: 0.28-0.92). This difference is statistically significant (p = 0.023). Toxicity was generally minimal in both arms. This randomized comparison of a combination of satraplatin and prednisone versus prednisone alone supports the antitumor activity of the combination. Its role in the treatment of HPRC remains to be elucidated in an appropriate phase III setting.

Evolving strategies of cytotoxic chemotherapy for advanced prostate cancer

Despite the use of cytotoxic chemotherapy for advanced prostate cancer for half a century, its clinical utility in this setting remains undefined. Based on traditional methods of assessment, the list of the most active cytotoxic agents includes cyclophosphamide, doxorubicin, mitoxantrone and cisplatin. With the introduction of more structured methods of assessment, including careful assessment of indices of quality of life and serial measurement of serum prostate-specific antigen (PSA), the role of cytotoxic agents is being re-assessed. In view of the cell cycle characteristics of prostate cancer, there appears to be an emerging role for combination inhibitors of mitosis, including estramustine in combination with the vinca alkaloids, etoposide or paclitaxel.

Estramustine phosphate versus placebo as second line treatment after orchiectomy in patients with metastatic prostate cancer: DAPROCA study 9002. Danish Prostatic Cancer Group

PURPOSE

We compared the effect of 560 mg. estramustine phosphate daily to placebo as a supplement to standard palliative therapy in patients with progressive disease after bilateral orchiectomy as first line therapy for metastatic prostate cancer.

MATERIALS AND METHODS

In a double-blind multicenter study 131 patients with progressing metastatic hormone refractory prostate cancer were randomized to receive 280 mg. estramustine phosphate 2 times daily versus placebo. End points were clinical progression and death. Adverse events, decrease in prostate specific antigen (PSA) and subjective response were also assessed.

RESULTS

Adverse events were common in both groups but breast tenderness/gynecomastia and diarrhea were more frequent among patients in the estramustine phosphate group. Subjective responses were few (9 of 50 estramustine phosphate and 4 of 57 placebo cases, p = 0.15). Median observation time for survival was 43 months and 124 patients died. Median time to subjective progression and median overall survival did not differ significantly between the 2 groups at 4.6 and 9.4 months in the estramustine phosphate group versus 5.0 and 6.1 months in the placebo group. Of 61 patients in the estramustine phosphate group 29 achieved a reduction in PSA of more than 25% at 1 month of followup compared to only 3 of 68 receiving placebo. A decrease in PSA after 1 month correlated significantly with survival.

CONCLUSIONS

Although this study did not prove estramustine phosphate to be superior to placebo in terms of protocol end points, it generates the hypothesis that prolonged survival may be achieved with estramustine phosphate treatment in a subgroup of patients and that this may be predicted by a decrease in PSA after 1 month of therapy.

Is "off-protocol" chemotherapy for androgen-independent carcinoma of prostate warranted?

It is acceptable to treat HRPC patients with off-protocol chemotherapy if these patients do not accept protocol therapy or are ineligible for such therapy. The choice of cytotoxic agent needs to be individually assessed, depending on range of tolerable toxicities and personal preferences of the physician and patient. At the present time, single-agent therapy with oral or intravenous cyclophosphamide or mitoxantrone/prednisone may offer optimal palliation without undue side effects in a predictable number of patients.

Estramustine and vinblastine: use of prostate specific antigen as a clinical trial end point for hormone refractory prostatic cancer

The combination of estramustine phosphate and vinblastine sulfate, 2 agents with separate and unique antimicrotubular effects, has demonstrated additive cytotoxicity against the DU145 human prostate derived cell line in vitro. We evaluated this combination in 25 patients with progressive hormone refractory prostate cancer. Of 24 patients with an elevated prostate specific antigen (PSA) level at the start of treatment 13 (54%, 95% confidence limits 34 to 74%) had a greater than 50% decrease in PSA levels on at least 3 consecutive biweekly determinations. The median decrease in PSA in responding patients was 64% (mean 71.7%) and the median duration of response was 7 months. In 5 patients with bidimensionally measurable disease 2 partial responses were observed. Treatment was well tolerated, with mild and manageable toxicity. This is a well tolerated outpatient treatment regimen for patients with hormone-refractory prostatic cancer which deserves further investigation.

Phase II study of platinum and mitoxantrone in metastatic prostate cancer: a Southwest Oncology Group Study

44 eligible patients with measurable or evaluable metastatic prostate cancer were treated with monthly cycles of cisplatin and mitoxantrone. Good-risk patients received cisplatin 60 mg/m2 intravenously and mitoxantrone 10 mg/m2 intravenously every 4 weeks. The dose in poor-risk patients (elderly or white blood cell count less than 4000/microliters, 4 x 10(9)/l, or extensive prior radiation) was reduced to 8 mg/m2. Toxicity was manageable and consisted primarily of myelosuppression. There were no complete responses and the partial response rate was only 12%. Median progression-free survival was 2.7 months for measurable and 4.1 months for evaluable disease patients. Median survivals were 4.9 and 8.7 months, respectively. This combination has minimal activity in hormone refractory metastatic prostate cancer.

Leuprorelin acetate depot: results of a multicentre Japanese trial. TAP-144-SR Study Group

The clinical efficacy and safety of 3.75 or 7.5 mg leuprorelin acetate depot given subcutaneously once every 4 weeks was evaluated in a collaborative study of 81 patients with untreated prostatic cancer. Efficacy of treatment was assessed using criteria based on a meeting of the Prostatic Cancer Study Group funded by the Japanese Ministry of Health and Welfare and using National Prostatic Cancer Project criteria. Japanese criteria enabled evaluation of individual parameters, unlike the National Prostatic Cancer Project system which classified a patient as unevaluable if one evaluation parameter was unavailable. Leuprorelin acetate depot suppressed serum luteinizing hormone, follicle stimulating hormone and testosterone concentrations. Objective response rates of the prostate, bone metastases, serum prostatic acid phosphatase and soft tissue metastases, and subjective dysuria and pain responses were comparable to those found with conventional hormone therapy. Leuprorelin acetate depot was well tolerated, with no significant differences in response to the two doses.

Failure of chemotherapy to prolong life in patients with metastatic prostate cancer who have failed androgen deprivation

Using historical controls, we analyzed the effect of chemotherapy on survival of patients with metastatic prostate cancer who failed androgen deprivation. The survival of 178 patients with metastatic prostate cancer who receive palliation only after failing hormonal therapy was compared with the survival of 27 patients who received chemotherapy on NPCP Protocol 1500. Survival was measured from the initiation of androgen deprivation. The mean survival after chemotherapy was 8.4 months which was slightly less than the group receiving palliation only. At this time, chemotherapy has not been able to improve survival in patients with metastatic prostate cancer.

The stable state is not an objective response in hormone-escaped carcinoma of prostate

In some clinical trials the use of criteria of stable response of hormone-escaped prostate cancer is justified on the ground that it delineates patients with markedly improved survival, similar to that of partial regression patients. Forty-three patients with hormone-escaped prostate cancer were studied in order to identify other factors which might also predict improved survival. Fifteen patients received palliative treatment only, 17 secondary hormone therapy and 11 chemotherapy. Only one objective partial regression was seen. Thirty-seven patients have died of prostatic cancer, 3 have died of other causes and 3 remain alive. The mean initial hormone response was 14.8 months, the mean time from progression to death 11.3 months, and the mean time from symptoms to death 5.9 months. There was no significant correlation between length of initial response and survival following progression (r = 0.25). Six features of progression were reviewed. Patients presenting with one feature of progression had a significantly better mean survival, 14.8 months, compared with 8.2 months when multiple features indicated progression. It is concluded that the stable state is not an objective response in hormone-escaped carcinoma of prostate but a reflection of the patient's natural disease progression and that the mode of presentation may be a significant prognostic indicator.

A reexamination of the stable category for evaluating response in patients with advanced prostate cancer

Stable response to therapy in patients with advanced prostate cancer, as experienced in clinical trials of the National Prostatic Cancer Project (NPCP) has been re-examined. Data from 10 completed trials, totaling over 1300 patients, have been examined for survival patterns within categories of response to therapy. Survival patterns, for patients alive at 12 weeks, were significantly poorer for patients who were categorized as progressors after 12 weeks on treatment than for those who were categorized as stable or as partial regressions. Furthermore, comparisons of survival patterns for those patients who were categorized as stable or partial regression revealed no statistically significant differences between them. The concerns over the use of stable as an indicator of response and the problems in establishing its true meaning are discussed. All things considered, the use of stable is a valid means to evaluate the status of patients in clinical trials of treatment modalities for advanced cancer of the prostate.

Stable versus partial response in advanced prostate cancer

Stable response to therapy in patients with advanced prostate cancer, as experienced in clinical trials of the National Prostatic Cancer Project (NPCP), has been reexamined. Data from ten complete trials totaling over 1,300 patients have been examined for survival patterns within categories of response to therapy. Survival patterns, both for all patients and for those alive at 12 weeks, were significantly poorer for patients categorized as progressors after 12 weeks on treatment than for those categorized as stable or as partial regressions. Furthermore, comparisons of survival patterns for those patients categorized as stable or partial regression revealed no statistically significant differences between them. The similarity of survival for the stable and partial regression categories indicates that the stable category represents more than a segment of the population with slowly progressing disease and can be taken as an indicator of response to therapy.

The addition of chemotherapy to hormonal therapy for treatment of patients with metastatic carcinoma of the prostate

Patients with advanced prostate carcinoma that had been stabilized by orchiectomy (ORCH) or hormone therapy for at least 3 months, were randomized to either diethylstilbestrol (DES) alone or DES plus Cytoxan or DES plus Emcyt. A total of 188 patients were randomized between July, 1976 and February, 1982 of which 161 were evaluable for objective response to treatment. Objective response rates, response duration, or survival experiences were not demonstrably different between treatment arms, either for all patients or within good or poor prognosis groups determined by initial pain or acid phosphatase level. Subjective improvements in performance status were small for each treatment. Pain relief was somewhat greater in the chemotherapy-hormone combinations than in the DES/ORCH, but the advantage was not statistically significant. Side effects were primarily nausea and vomiting and leukopenia, mostly in the DES + Cytoxan arm. The duration of stabilization prior to entry did not influence response overall, although there were opposing trends within each of the two chemotherapy arms. The premise for combining antitumor agents with hormones before hormone failure is still felt to be a more logical approach than waiting for the ultimate hormone failure, and a combination of hormones plus two antitumor agents is being evaluated in a subsequent ongoing trial where a more rigid design limits the duration of the preentry period of hormone stabilization.