The oestrogenic effects of ethinyl oestradiol/polyoestradiol phosphate and estramustine phosphate in patients with prostatic carcinoma. A comparative study of oestrogen sensitive liver proteins, gonadotrophins and prolactin

Role of androgen deprivation treatment in patients with castration-resistant prostate cancer, receiving docetaxel-based chemotherapy

OBJECTIVES

To assess the impact of continued androgen deprivation therapy (ADT) in patients with castration-resistant prostate cancer (CRPC) receiving first-line docetaxel-based chemotherapy.

METHODS

A retrospective review was performed on 78 patients fulfilling the criteria for CRPC who were treated with docetaxel-based chemotherapy over 5 years.

RESULTS

Thirty-nine patients received concurrent ADT (ADT group), whereas 39 patients discontinued ADT (No-ADT group). PSA response rates were 66.7% for ADT patients and 48.7% for No-ADT patients (P = 0.27). The median progression-free survival and overall survival were 5.0 months and 24.8 months for ADT patients and 4.9 months and 22.1 months for No-ADT patients, respectively (P = 0.57, P = 0.94). Follow-up testosterone levels were available in 13 patients of the No-ADT group and none of them recovered a normal serum testosterone level over a median follow-up duration of 8.3 months from ADT discontinuation. ADT was recommenced in 21 of 39 patients in the No-ADT group and, of these, 6 (29%) achieved a PSA response.

CONCLUSION

Clinical outcomes were not significantly different when patients with CRPC received concurrent ADT, or were not so treated, when receiving first-line docetaxel-based chemotherapy. Despite ADT withdrawal, serum testosterone level did not recover to the noncastrated level during the period of chemotherapy, and reinduction of hormone sensitivity occurred in about one-quarter of patients.

Parenteral oestrogen in the treatment of prostate cancer: a systematic review

The objectives of this study were to assess the effectiveness and safety of parenteral oestrogen in the treatment of prostate cancer, and to examine any dose relationship. A systematic review was undertaken. Electronic databases, published paper and internet resources were searched to locate published and unpublished studies with no restriction by language or publication date. Studies included were randomised controlled trials of parenteral oestrogen in patients with prostate cancer; other study designs were also included to examine dose-response. Study selection, appraisal, data extraction and quality assessment were performed by one reviewer and independently checked by another. Twenty trials were included in the review. The trials differed with regard to the included patients, formulation and dose of parenteral oestrogen, comparator used, outcome measures reported and the duration of follow-up. The results provide no evidence to suggest that parenteral oestrogen, in doses sufficient to produce castrate levels of testosterone, is less effective than luteinising hormone-releasing hormone (LHRH) or orchidectomy in controlling prostate cancer, or that it is consistently associated with an increase in cardiovascular mortality. Further well-conducted trials of parenteral oestrogen are required. A pilot randomised controlled trial comparing transdermal oestrogen to LHRH analogues in men with locally advanced or metastatic prostate cancer is underway in the United Kingdom.

Phase I clinical and pharmacologic trial of intravenous estramustine phosphate

PURPOSE

To determine the dose-limiting toxicities, maximum-tolerated dose, and pharmacokinetics of intravenous estramustine phosphate (IV EMP).

PATIENTS AND METHODS

A total of 31 patients with hormone-refractory prostate cancer received IV EMP as a 30- to 90-minute infusion weekly (n = 28) or for 3 consecutive days followed by a single weekly dose (n = 3). IV EMP dose was escalated from 500 to 3,000 mg/m(2). Pharmacokinetics of EMP and the metabolites estramustine (EaM), estromustine (EoM), estradiol, and estrone were assessed after weeks 1 and 4 of treatment.

RESULTS

The initial IV EMP infusion caused perineal discomfort that was ameliorated by lengthening the infusion time. Other common toxicities were grade 1 to 2 hepatotoxicity, nausea or vomiting, and fatigue or malaise. Lower-extremity thrombosis occurred in one patient, and two others developed upper-extremity thrombosis associated with venous infusion catheters. Dose-limiting fatigue and hypotension occurred at 3,000 mg/m(2), and cumulative fatigue developed after multiple cycles at 2,500 mg/m(2). Mean EMP clearance, estimated steady-state volume of distribution, and elimination half-life were 3.7 L/h, 10.6 L, and 3.7 hours, respectively. Variability of EMP clearance was 21%, and variation in area under the curve per dose for the metabolites was 28% to 36%. Elimination half-lives of EoM and EaM were 110 hours and 64 hours, and peak plasma concentrations of these active metabolites exceeded 10 micromol/L after IV EMP doses greater-than-or-equal 2,000 mg/m(2).

CONCLUSION

High-dose IV EMP can be administered safely as a weekly short infusion to patients with HRPC. High peak concentrations of active metabolites after IV EMP may provide an advantage over oral EMP in antimicrotubule drug combinations.

Parenteral estrogen versus total androgen ablation in the treatment of advanced prostate carcinoma: effects on overall survival and cardiovascular mortality. The Scandinavian Prostatic Cancer Group (SPCG)-5 Trial Study

OBJECTIVES

To compare the effect on overall survival of total androgen ablation (TAA) with that of parenteral estrogen and to pay special attention to cardiovascular mortality. TAA (orchiectomy or a luteinizing hormone-releasing hormone analogue combined with an antiandrogen) has been proposed as superior to other endocrine treatments for patients with prostate carcinoma. Recently, the use of parenteral estrogen has been suggested to reduce or even negate the well-known cardiovascular side effects of oral estrogens.

METHODS

Nine hundred fifteen patients were randomized to intramuscular injections of 240 mg polyestradiol phosphate (PEP) every second week for the first 8 weeks (5 doses) followed by a maintenance dose of 240 mg every month (n = 458) or to bilateral orchiectomy or triptorelin 3.75 mg every month combined with the antiandrogen flutamide 250 mg three times daily. The choice between orchiectomy and triptorelin was at the discretion of the clinician and patient. Patients were stratified according to performance status, presence of cardiovascular disease, and alkaline phosphatase level. An observer totally unaware of the treatment given classified all deceased patients.

RESULTS

At a median follow-up of 18.5 months, no signs of a difference in overall survival were found between TAA and PEP (P <0.001). Of 458 patients, 266 (58.1%) had died in the PEP group compared with 269 (58.9%) of 457 patients in the TAA group. Within the TAA group, no difference in overall survival existed between patients who had undergone orchiectomy or who were given triptorelin. Furthermore, no differences in cardiovascular mortality were found (3.5% in the PEP group and 3.1% in the TAA group).

CONCLUSIONS

The current parenteral estrogen regimen seems to be of comparable efficacy and cardiovascular safety as TAA in terms of overall survival. PEP has by far the lowest drug cost and also the lowest cumulative direct costs and thus has the highest cost-effectiveness. We suggest that parenteral estrogen be included as a therapeutic option in the endocrine management of prostate carcinoma.

Time for revival of estrogens in the treatment of advanced prostatic carcinoma? Pharmacokinetics, and endocrine and clinical effects, of a parenteral estrogen regimen

BACKGROUND

The present pilot study tested the clinical performance of a new pharmacokinetically guided dosing regimen of parenteral estrogen in patients with advanced prostatic carcinoma. The aim was to accelerate endocrine effects and to avoid cardiovascular side effects.

METHODS

Seventeen patients were randomized to intramuscular injections of 240 mg polyestradiol phosphate (PEP) every second week for the first 8 weeks (five doses), followed by a maintenance dose of 240 mg every month; and 16 patients were randomized to bilateral orchidectomy. The estrogen dosing was calculated by pharmacokinetic modelling to achieve a rapid increase in serum estradiol and thereby a fast decrease in testosterone.

RESULTS

The predicted increment in serum estrogen was achieved, together with a subsequent decrease in testosterone in the PEP group. In addition, there were no signs of an increased cardiovascular morbidity. This was probably due to a minimal estrogenic influence on the liver and was reflected by unchanged levels of coagulation factor VII. Clinical effects, during the first 2 years of treatment, were similar in the two treatment arms, with 12 patients in the orchidectomy group and 14 patients in the PEP group responding to treatment.

CONCLUSIONS

The present parenteral regimen is an efficient and time-saving estrogen regimen with a favorable side-effect profile. PEP seems to offer a potential for revival of the most cost-effective endocrine treatment of cancer of the prostate, i.e., estrogen.

Effects of ethinyl oestradiol/polyoestradiol phosphate and estramustine phosphate on some proteins related to haemostasis in prostatic carcinoma patients

Twenty-four previously untreated patients with carcinoma of the prostate were prospectively randomized to one of the following treatments: (1) ethinyl oestradiol combined with polyoestradiol phosphate (EE/EP); (2) estramustine phosphate (EM); (3) bilateral orchiectomy. The effects on some plasma proteins related to haemostasis were studied by measuring the concentrations of alpha-1-antitrypsin, orosomucoid, haptoglobin, antithrombin III, C1-inhibitor and von Willebrand's factor before and 3 months after the start of treatment. Orchiectomy induced a reduction of alpha-1-antitrypsin and haptoglobin, while the other studied proteins were unaffected. It was found that both EE/EP and EM treatment induced significant decreases of orosomucoid, haptoglobin, antithrombin III and C1-inhibitor, while the same treatment increased the plasma concentration of alpha-1-antitrypsin. None of these treatments showed any influence on the plasma concentration of the von Willebrand factor. No differences were observed between EE/EP and EM for any of the studied proteins, suggesting comparable oestrogenic effects of these forms of treatment in patients with prostatic carcinoma. The findings are discussed in relation to the proposed difference in thromboembolic complications between EE/EP and EM treatments of prostatic carcinoma patients.

Orchiectomy versus oestrogen in the treatment of advanced prostatic cancer

The primary clinical efficacy of orchiectomy and the combination therapy of intramuscular polyoestradiol phosphate 80 mg monthly and oral ethinyl oestradiol 0.15 mg daily was evaluated by progression and cancer mortality rates in a series of 277 prostatic cancer patients representing part of the Finnprostate study. After a follow-up of 5 years there was a significant difference between the groups in terms of progression rate and prostatic cancer deaths. The oestrogen combination was more effective in delaying progression of the disease. The overall mortality rate was similar in both groups. About one-third of the patients were alive after 5 years.

Oestrogen dosage in prostatic cancer: the threshold effect?

We present the results of a prospective randomised trial of Estradurin, a long-acting oestrogen preparation (polyoestradiol phosphate), 160 mg per month, compared with bilateral orchiectomy in patients with advanced prostatic carcinoma (T3M1; T4MO/M1). The dose was lower than that usually recommended to induce a consistent fall in serial plasma testosterone levels to within the castrate range. Most patients treated with oestrogen showed an initial clinical and biochemical response equal to that obtained for patients undergoing orchiectomy. The inevitable relapse in hormone sensitivity sometimes occurred very soon after the start of oestrogen treatment. Many patients had poorly suppressed plasma testosterone expressed as a mean of monthly serial measurements, but then responded to secondary orchiectomy. These data only suggest that, in the treatment of hormone-sensitive prostatic carcinoma, it may be necessary to reduce plasma testosterone to midway between castrate and normal ranges. The data support the theory that response to androgen withdrawal is qualitative rather than quantative. The effective dose of oestrogen may therefore be reduced and the risk of thrombo-embolic complications minimised.

Effects of estrogen on the human pituitary: a clinicopathologic study

Pituitary glands obtained at autopsy of 67 men treated with diethylstilbestrol were examined for diffuse and nodular lactotrophic hyperplasia as well as prolactin cell tumorlets or adenomas. A control group consisted of 42 untreated patients with prostatic carcinoma and 209 other elderly men. Diffuse and nodular lactotrophic hyperplasia and the percentage of prolactin cells were greater in treated patients, but these differences were not statistically significant. The higher frequency of prolactin cell adenomas among treated patients (19%) than among control subjects (11%) also lacked statistical significance. An apparent low frequency of occurrence of adenoma in control patients with prostatic carcinoma remains unexplained. No correlation was noted between tumor number, size, morphologic features, or immunoreactivity and such factors as dose of estrogen therapy, associated diseases, ultimate cause of death, or patient age. A correlation was noted, however, between duration of estrogen therapy and the total number of pituitary adenomas, including those composed of prolactin cells. Relative proportions of other types of adenoma were similar within the study and control groups. We conclude that estrogen medication cannot be considered a major risk factor in the cause of prolactin-producing adenomas in older men.

On the regulation of sex-hormone-binding globulin--a challenge of an old dogma and outlines of an alternative mechanism

In this review, the different factors known to affect SHBG levels are discussed with respect to their possible significance in the physiological regulation of this protein: Sex steroids, puberty, nutritional status, thyroid hormones and liver disease. It is concluded that the serum levels of SHBG are related to general metabolic factors, nutritional status, growth and ageing than to the estrogen/androgen balance. The authors suggest that SHBG is regulated primarily by growth hormone, somatomedin-C and possibly other growth factors. Growth hormone may promote SHBG synthesis in the liver while somatomedin-C may stimulate its extravasation and uptake in target tissues. It is suggested that sex steroids merely have an indirect, modulating influence.

Estrogen therapy and liver function--metabolic effects of oral and parenteral administration

Oral estrogen therapy for prostatic cancer is clinically effective but also accompanied by severe cardiovascular side effects. Hypertension, venous thromboembolism, and other cardiovascular disorders are associated with alterations in liver metabolism. The impact of exogenous estrogens on the liver is dependent on the route of administration and the type and dose of estrogen. Oral administration of synthetic estrogens has profound effects on liver-derived plasma proteins, coagulation factors, lipoproteins, and triglycerides, whereas parenteral administration of native estradiol has very little influence on these aspects of liver function.

Uptake of estramustine phosphate (estracyt) metabolites in prostatic cancer

Plasma and tumour concentrations of estramustine, estromustine, estradiol and estrone, the major metabolites of estramustine phosphate (estracyt), were determined in patients with prostatic carcinoma treated between one and nine years with repeated oral doses of estracyt (560 to 840 mg./day). The last dose was given 12 to 16 hours before sampling. The binding of radioactive estramustine and estromustine was determined in the tumour tissue to examine the possible role of estramustine-binding protein for the accumulation of these metabolites into the tumour. Comparison was made with benign prostate hyperplastic tissue from untreated patients. Estromustine was the main metabolite in plasma as well as in the tumour (range 235 to 450 and 205 to 485 ng./gm., respectively), whereas estramustine (20 to 45; 95 to 370), estrone (62 to 140; 63 to 160) and estradiol (8 to 15; 7 to 36) were found in lower concentrations. Interestingly the concentration of estramustine was as an average six times higher in the tumour than in plasma contrasting with the other metabolites which were present in equal amounts of the two localities. Binding of 3H-estramustine and 3H-estromustine was two to three times higher in the tumour than in benign hyperplastic tissue and negligible in plasma samples. The present study is the first where substantial amounts of cytotoxically active estramustine and estromustine are demonstrated in tumour tissue from estracyt treated patients. Our findings suggest a mechanism for selective uptake of these metabolites in prostatic cancer (estramustine-binding protein). The uptake and binding of estramustine and estromustine in the tumour may account for the clinical effects of estracyt in prostatic carcinoma.

Steroid-sensitive proteins, growth hormone and somatomedin C in prostatic cancer: effects of parenteral and oral estrogen therapy

The effects of parenteral and parenteral plus oral estrogen therapy on the serum levels of sex hormone binding globulin (SHBG), pregnancy-associated alpha 2-macroglobulin (alpha 2-PAG), growth hormone (GH), and somatomedin C (SmC) were studied in 26 patients with prostatic cancer. Intramuscular polyestradiol phosphate treatment, yielding a mean serum level of estradiol-17 beta of 1,446 pM and a mean testosterone level of 4.5 nM, had no significant effects on alpha 2-PAG, GH, and SmC and increased SHBG levels only marginally. Combined treatment with intramuscular polyestradiol phosphate and oral ethinyl estradiol greatly increased SHBG and alpha 2-PAG levels and caused elevated GH and decreased SmC levels. The route of estrogen administration is probably of major importance for the hormonal effects on hepatic activity as reflected by SHBG and alpha 2-PAG levels. Bypassing the portal circulation might be advantageous with respect to liver-related side effects of estrogen therapy. GH and SmC might act as mediators of estrogen effects on the human liver.