Flutamide in hormone-resistant prostatic cancer

The course of metastatic prostate cancer under treatment

The first-line management of metastatic prostate cancer is hormonal therapy. However, resistance to this treatment will emerge within an average of 24 months. Our purpose was to determine the course of metastatic prostate cancer under treatment.

A total of 56 patients who were diagnosed with metastatic prostate cancer were enrolled. As initial management, 3 kinds of hormonal therapy consisting of bilateral orchiectomy (BSO) alone, BSO + anti-androgene (AA) and LH-RH + AA were applied. The patients were followed until the emergence of hormone resistance. Serum PSA levels at the time of first diagnosis, post-treatment nadir PSA levels, time to nadir PSA, time to hormonal resistance and PSA levels at hormonal resistance were assessed, retrospectively. The localization and number of metastases and the survival term from the beginning of the emergence of hormone resistance until death were investigated

No significant differences could be established between the groups. The mean time to reach hormone refractory status was 30.3 months for the whole study group. The average term of survival was 42.7 months for the whole group. Distance metastases were found in 8 patients during follow-up.

There were no statistical differences between the groups in terms of treatment modalities applied for metastatic prostate cancer. Patients with androgen independent prostate cancer demonstrated progression despite chemical or surgical castration, and had poor prognosis. Initial hormonal therapy failed after an average of 2 years in metastatic prostate cancer.

The role of hormonal treatment in prostate cancer

In 1941 Huggins and Hodges published for the first time the favorable effects of surgical castration and estrogen treatment on the progression of metastatic prostate cancer. However, this hormonal therapy is not without side effects. Since this pioneering milestone in history of prostate cancer, a further tremendous innovation did not take place. Today, due to intensive clinical, biochemical, nuclear-biological and molecular-biological research, many hormone active treatment variations are available. Besides traditional hormonal therapy, surgical or chemical castration, maximal androgen blockade, nontraditional forms of hormonal therapy, intermittent hormonal therapy, antiandrogens, 5-alpha-reductase inhibitors, and their combinations, we discuss options toward creating an increased number of side effect-oriented offers of hormonal treatment options, guaranteeing a longer and more comfortable exhaustion of the individual hormonal period of response and probably a longer survival. The prerequisite is a closer-than-ever monitoring by tumor marker and an early observation of symptomatic changes.

Treatment algorithm in hormone-resistant prostate cancer: Practical guidelines

Treatment of hormone-resistant prostate cancer can be a challenging situation. The first important step in treating this condition is to assess if one has achieved the castrate level or not. If the castrate levels are not achieved, attempt should be made to achieve so. If the castrate level is achieved, then androgen withdrawals may be of help. Supportive care, care of the clinical problems forms an integral part of the treatment. Cancer-specific chemotherapy is certainly an option in progressive disease.

Secondary Hormonal Manipulations in Prostate Cancer

Targeting AIPC with therapies that affect the mechanisms of androgen receptor signaling despite a castrate testosterone milieu is an active and growing area of clinical research. At present, for patients with AIPC, the data support the maintenance of the castrate state, recognition of the AAWD phenomenon,the sequential use of oral antiandrogens, and a trial of estrogens or adrenal androgen-targeted therapies. Novel agents are being developed that seek to prolong the duration of clinical responses and the overall response rate.

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.

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.

A modified low-dose regimen of mitoxantrone and prednisolone in patients with androgen-independent prostate cancer

BACKGROUND

We conducted this retrospective study to analyze a modified dose schedule of mitoxantrone and prednisolone (MP) in patients with androgen-independent prostate cancer.

METHODS

From June 1997 to April 2002, 28 patients were enrolled. Their median age was 69 years (range, 58-79 years). The median duration of hormonal therapy was 30 months (range, 6-84 months). The median performance status was 2. Sixteen of the patients had bone disease only. The chemotherapy consisted of 8 mg/m2 mitoxantrone by intravenous infusion every 3 weeks and 10 mg prednisolone orally twice per day. WHO response criteria, prostatic-specific antigen (PSA), pain and performance status were used to assess the response.

RESULTS

The median number of treatment cycles was six (range, 2-20). Nine (32.1%) and 15 patients (53.8%) had > or =80% and > or =50% reduction in serum PSA level, respectively. Of 16 patients using narcotics, five (31.3%) had a > or =50% reduction in narcotics consumption compared with the baseline. Nine patients (32.1%) showed improved performance. For 12 patients with measurable disease, only two (16.7%) showed a partial response. Grade 3-4 toxicities included neutropenia (three patients), anemia (three patients) and vomiting (one patient). The median survival was 12 months and the median time to PSA progression was 4 months.

CONCLUSIONS

This modified regimen is feasible for palliative intent. The toxicity of this regimen is manageable. Exploring further combinations of this regimen with novel agents against androgen-independent prostate cancer is warranted.

Management of Hormone-Sensitive and Hormone-Refractory Metastatic Prostate Cancer

BACKGROUND: Prostate cancer is a significant health problem in the United States and is the focus of increasing attention in our society. With the aging of the US population, it is likely that prostate cancer will continue to grow in importance. The options for systemic therapy of metastatic prostate cancer should be familiar to physicians, including nonspecialists, whose patients seek their advice and counsel. METHODS: Past and recent literature was surveyed to provide an understanding of the systemic treatment of advanced prostate cancer. The author presents a review of the systemic treatment of metastatic prostate cancer in different clinical circumstances and addresses the current status of chemotherapy in the management of advanced prostate cancer. RESULTS: Early androgen deprivation used over prolonged periods appears to be modestly superior to delayed androgen deprivation with a small potential survival advantage and an advantage in delaying disease progression in advanced prostate cancer. Patients with hormone-refractory prostate cancer may benefit from secondary hormonal therapy (eg, adrenal enzyme inhibitors, antiandrogens, glucocorticoids) and chemotherapy. CONCLUSIONS: The choices of therapy for metastatic prostate cancer depend on individual patient preference. Patients and physicians should be aware of the possible side effects associated with the therapeutics options for treatment of metastatic prostate cancer.

High dose bicalutamide for androgen independent prostate cancer: effect of prior hormonal therapy

PURPOSE

A pilot study of the antiandrogen bicalutamide at 150 mg. a day for androgen independent prostate cancer was performed. This study was based on the possibility that androgen independent cases might display responses to additional hormonal agents.

MATERIALS AND METHODS

The study included 31 androgen independent cases with an increasing prostate specific antigen (PSA) and progressive disease. PSA measurements were used as the primary method of assessing response. However, PSA decline was also correlated with clinical status.

RESULTS

Seven patients demonstrated PSA declines of greater than 50% for 2 months or more, for an overall response rate of 22.5%. Responses were observed almost exclusively in patients treated with long-term flutamide as part of a complete androgen blockade regimen (43% response rate) in contrast to patients treated with androgen deprivation without flutamide (6% response rate). Of the 7 PSA responding patients bicalutamide resulted in a significant improvement in performance status and a decrease in analgesic requirement in 4 and 3 remained asymptomatic. Bicalutamide at 150 mg. a day was well tolerated, with the most frequent side effect being mild exacerbation of hot flashes.

CONCLUSIONS

Bicalutamide at this dose is modestly effective for some patients with androgen independent prostate cancer, particularly for those previously treated with long-term flutamide. This study indicates that previous antiandrogen therapy alters the response to subsequent hormonal agents.

Steroid hormone withdrawal syndromes. Pathophysiology and clinical significance

The steroid withdrawal syndrome has brought a new dimension to the treatment of advanced prostate cancer not only in the way we treat androgen-independent disease but also in terms of insights into the development of hormonal resistance. The data now confirm that 30% of cases have a meaningful subjective, biochemical, and objective response to the withdrawal of a steroid hormone as the first maneuver after primary hormonal therapy failure. Larger studies are needed to define further the withdrawal effect related to the other steroid hormone family members and to determine the objective response proportions. Although controversy surrounds the cause of the steroid withdrawal phenomenon, studies suggest that the androgen receptor plays a pivotal role. Molecular studies of the androgen receptors involving larger number of patients are paramount if we are going to develop a better understanding of the evolution of the withdrawal effect and hormone resistance.

Treatment of metastatic carcinoma of the prostate

Disseminated carcinoma of the prostate (CaP) is a common manifestation of this disease. Metastatic CaP in the United States is seen in about 45,000 patients each year at diagnosis. At least the same number of patients who have had prior definitive treatment with surgery or radiotherapy develop evidence of metastatic disease. Hormonal management is the most important and well established treatment for patients with prostatic metastases. Orchiectomy remains the most efficient and most cost effective therapy in a rapid ablation of testicular androgens. Due to a well known psychological reaction to castration which is seen in many patients, diethylstilbestrol (DES) is a good alternative and cost effective therapy. The mode of action of DES is to suppress LH production and to slowly, indirectly, decrease serum testosterone level. In recent years, total androgen blockade (TAB) has become a widely accepted treatment option. This treatment has been shown in several clinical trials to be effective and well tolerated by the patients. A major problem with a routine use of TAB is a relatively high cost of this therapy. In a European prospective randomized trial, goserelin acetate-flutamide combination significantly increased time to progression when compared with orchiectomy alone. Patients with localized and symptomatic metastases are best treated with radiotherapy. Those with multiple sites of involvement are best treated with strontium-89 which results in a good palliation in a majority of patients. Nearly all hormonally treated patients, with metastatic CaP, eventually show tumor progression. Presently available chemotherapy is of a low effectiveness and should not be used for these patients outside of controlled clinical trials. Current research is directed to identify effective therapy for hormone refractory patients. Immunotherapy and gene therapy may be useful future therapeutic options.

Treatment of metastatic prostate cancer. Lessons from the androgen receptor

The exquisite hormonal dependence of prostate cancer continues to provide an opportunity and a challenge for oncologists. It is clear that future efforts in the laboratory should include determining the frequency and spectrum of AR mutations in AI prostate cancer, the development of more effective antiandrogens, and understanding in greater detail how the AR stimulates the growth of prostate cancers. These efforts may eventually lead to treatments that greatly reduce any stimulatory effects of the AR on prostate cells, possibly resulting in a significant improvement in disease-free survival and, perhaps in conjunction with other modalities, cure of some earlier stages of disease. And even for patients with advanced disease, because hormonal therapy is generally fairly well tolerated even in the typically older prostate cancer patient, defining the contribution of AR-mediated growth to AI disease will be critically important.

Treatment of Androgen-Independent Prostate Cancer

Androgen-ablative therapy for metastatic prostate cancer is effective for 60%-80% of men, but its effects are always finite and the majority of men develop androgen-independent disease within two years. Although current therapies for androgen-independent disease have not been shown to impact on survival, recent clinical and laboratory insights offer hope for effective therapy. For instance, recent data indicate that androgen-independent disease may still be dependent on hormonal stimulation, suggesting that hormonally based therapies may provide continued benefit. Chemotherapy, especially with estramustine and etoposide, seems to be an effective combination for a majority of patients. Treatment with suramin had been hampered by its side effects, but new dosing schedules are effectively circumventing toxicity. Radioisotopes such as strontium 89 have been shown to provide effective palliation for a majority of androgen-independent patients. Overall, these and other emerging efforts may be the foundation for therapies that offer hope for a significant survival benefit.

Prostate specific antigen after gonadal androgen withdrawal and deferred flutamide treatment

PURPOSE

We assess the impact of deferred flutamide treatment on the serum prostate specific antigen (PSA) level in patients with localized or metastatic cancer.

MATERIALS AND METHODS

The study included 45 patients with localized cancer and 50 with metastatic cancer with an increasing (87) or stable (8) PSA level after gonadal androgen withdrawal.

RESULTS

Of 40 evaluable patients with localized cancer and 50 with metastatic cancer 32 (80%) and 27 (54%), respectively, had a PSA decrease of 50% or more of baseline during flutamide treatment (p = 0.014). Among patients with localized cancer actuarial analysis of freedom from PSA elevation during flutamide treatment favored those with a 50% or greater PSA decrease (p = 0.006) but in patients with metastatic cancer the analysis revealed no significant difference.

CONCLUSIONS

The relative density of tumor cells that are dependent on adrenal androgen after gonadal androgen withdrawal may be greater in patients with localized cancer and deferred flutamide treatment may enhance cancer control in those with localized disease.

Weekly chemotherapy in advanced prostatic cancer

This randomised phase II study was performed in order to evaluate the effectiveness of a weekly chemotherapy regimen in advanced prostatic carcinoma patients (stage D2) refractory to hormonal therapy. Seventy-two cases were studied: they were randomised in a 2:1 ratio to receive either epirubicin (30 mg m-2 weekly) or doxorubicin (25 mg m-2 weekly); 48 patients received epirubicin and 24 received doxorubicin. After 12 courses of chemotherapy, the 45 evaluable patients in the epirubicin arm showed a response rate of 37.7% and the 21 evaluable patients in the doxorubicin arm showed a response rate of 33.3% (P = 0.51). Pain intensity, bone and prostatic tumour markers rapidly and significantly decreased in responders. An improvement in physical symptoms, functional conditions and in emotional well-being was observed in the majority of the treated patients. The histological analysis of bone metastases, performed before and after 12 courses of chemotherapy showed a significant reduction in neoplastic invasion and in new bone formation in responders. Cardiac performance worsened in five out of 45 patients and in ten out of 21 during the first 12 courses of epirubicin or doxorubicin respectively (P = 0.014). The median survival was 12.5 months in the epirubicin arm and 8.0 months in the doxorubicin arm (P = 0.042). Our data indicate that in advanced prostatic carcinoma, a weekly epirubicin regimen may give rapid palliative results, similar to that of doxorubicin, but with less side-effects.

Near fatal liver dysfunction secondary to administration of flutamide for prostate cancer

A 66-year-old man with metastatic prostate cancer was treated with bilateral orchiectomy and 750 mg. flutamide per day. Near fatal liver dysfunction developed 10 weeks later. Flutamide was discontinued and 8 weeks later liver enzymes had returned to normal.

89Strontium in bone metastases from hormone resistant prostate cancer: palliation effect and biochemical changes

Hematological and biochemical parameters were evaluated in 31 patients receiving 150 MBq 89Strontium (89Sr) intravenously due to painful skeletal metastases from hormone resistant prostate cancer. Two and 3 months after the injection prostate specific antigen (PSA) had increased by a median of 36% and 100%, respectively, as compared to the pretreatment value whereas alkaline phosphatase (APHOS) had decreased by about 20% (median). The leucocyte and platelet counts were reduced by about 20-35%, without reaching grade greater than or equal to 2 toxicity. Pain relief was reported in 14 of 29 evaluable patients at 2 months and in 11 of 23 patients at 3 months. It is concluded that 89Sr represents a worthwhile therapeutic modality in the palliation treatment of patients with hormone resistant prostate cancer, though the biological significance of frequently increasing PSA and decreasing APHOS is not yet completely understood.