Will the experience with tamoxifen in breast cancer help define the role of antiandrogens in prostate cancer?

131I labeling of tamoxifen and biodistribution studies in rats

Tamoxifen [TAM ([Z]-2-[4-(1,2-diphenyl-1-di-butenyl)-phenoxy]-N,N-dimethylethanamine)] has been used as an antiestrogen drug for treatment and prevention of human breast cancer. Tamoxifen was labeled with 131I using iodogen as an oxidizing agent. Mass spectroscopy of the cold standard showed that the labeling occurs in ortho position to the phenyl ether position of TAM as expected. Quality control, radiochemical yield and stability were established using the radioelectrophoresis method. The radiolabeled compound maintained its stability throughout working period of 24 h. Scintigraphic imaging was performed and tissue distribution was determined in Albino Wistar rats. According to biodistribution and imaging experiments the radiolabeled compound presented estrogen receptor (ER) specificity and it was uptaken by endometrium as well as breast tissue.

Early Prostate Cancer 2005 New 2005 data

The Early Prostate Cancer (EPC) Program consists of three randomised, double blind, placebo-controlled trials that assess bicalutamide either as adjuvant to treatment of curative intent or alone (radical prostatectomy, radiotherapy or watchful waiting) in patients with non-metastatic prostate cancer. In total, 8113 men have been enrolled in a 1/1 ratio to receive bicalutamide 150 mg/day orally or a matching placebo. We present the results at a median follow-up. No significant results are yet observed on overall survival in the localised, low-risk disease groups. For patients with locally advanced disease, adjuvant hormonal therapy significantly improves objective progression-free survival over placebo. Moreover, adjuvant bicalutamide offers a significant benefit in terms of overall survival in radiotherapy treated patients for locally advanced prostate cancer.

The diagnosis and treatment of osteoporosis in men on androgen deprivation therapy for advanced carcinoma of the prostate

PURPOSE

Androgen deprivation therapy (ADT) for advanced prostate cancer increases the risk of osteoporosis. Thus, the practicing urologist should be aware of the appropriate assessment and management. In this article we review the tests designed to diagnose osteoporosis as well as treatment options. We also review methods to monitor the response to therapy and make recommendations for management.

MATERIALS AND METHODS

We performed a MEDLINE (1966 to 2004) search for the terms male, osteoporosis, bone mineral density, prostate cancer, androgen deprivation therapy, bisphosphonates, estrogen and the combinations thereof. We then constructed a management algorithm based on the best evidence available.

RESULTS

Dual energy x-ray absorptiometry of the hip is the gold standard test for osteoporosis. Biochemical markers of bone turnover are not suitable for diagnosis but they have been shown to be useful for monitoring the response to treatment. Smoking cessation, weight bearing exercise, and vitamin D and calcium have been shown to help improve bone mineral density (BMD). Bisphosphonates have been demonstrated to increase BMD and decrease fracture risk in men with osteoporosis. Estrogens have also recently been shown to decrease bone turnover and increase BMD in men on ADT.

CONCLUSIONS

Hip dual energy x-ray absorptiometry should be performed in all men who are anticipated to be on long-term ADT. In addition, all men on ADT should receive vitamin D and calcium supplementation, and perform regular weight bearing exercise. The value of smoking cessation cannot be overstated. In men who have osteopenia or osteoporosis bisphosphonate therapy should be initiated. Estrogen therapy has shown promise but specific recommendations cannot be made at this time.

An evaluation of bicalutamide in the treatment of prostate cancer

Although prostate cancer is traditionally considered a disease of old age, improved diagnostic techniques have resulted in early diagnosis, and many men are now treated while still physically and sexually active. Current therapies for prostate cancer often include medical or surgical castration, which cause adverse effects on physical and sexual function; therefore, greater attention has been focused on quality of life. The nonsteroidal antiandrogen bicalutamide is an effective agent with a favorable tolerability profile and, in some settings, represents an alternative to castration. Mature survival data reveal that bicalutamide monotherapy provides survival benefits for untreated locally advanced disease that do not differ significantly from those of castration and maintains better physical capacity and sexual interest. Recent data from a prospective randomized trial demonstrate that bicalutamide given as immediate therapy, either alone or as adjuvant to therapy of curative intent, significantly reduces the risk of objective disease progression in patients with localized or locally advanced prostate cancer. Antiandrogens are also used in combination with castration, a treatment known as combined androgen blockade (CAB), for advanced disease. A randomized trial demonstrated that CAB with bicalutamide is associated with similar survival outcome to CAB with flutamide and is better tolerated. Current evidence demonstrates that bicalutamide currently has a favorable risk-benefit ratio in several stages of prostate cancer and that the role of bicalutamide will be further defined by ongoing studies.

Preventing diseases of the prostate in the elderly using hormones and nutriceuticals

The prostate has only one function, namely to secrete fluid containing substances that are needed for reproduction. This requires an extremely high concentration of androgens in the tissues. Benign prostatic hypertrophy (BPH) seems to be related to the long-term exposure of the prostate to the strong androgen 5alpha-dihydrotestosterone (DHT) and, possibly, to estrogens. The relation between prostate cancer and androgens is suggested to be U-shaped, with both extremes of androgen concentrations being associated with increased risk of invasive cancer. In the treatment of patients with BPH, the lipidic liposterolic extracts of Serenoa repens were as effective as the pharmaceutical inhibitors of the 5alpha-reductase enzyme or alpha1-adrenergic blockers in relieving urinary symptoms. In addition to moderately inhibiting the 5alpha-reductase activity, Serenoa seems to exert anti-inflammatory and complementary cellular actions with beneficial effects on the prostate. Unlike the pharmaceutical 5alpha-reductase inhibitors, finasteride and dutasteride, Serenoa does not suppress serum PSA, facilitating the follow-up and the early detection of prostate cancer. We suggest a strategy to prevent prostate cancer that aims at providing men with partial androgen deficiency correct testosterone substitution with a sustained release buccal bio-adhesive tablet. In addition, food supplementation with extracts of Serenoa repens and a combination of the antioxidants selenium, (cis)-lycopene and natural vitamin E, together with fish oil rich in long-chain polyunsaturated essential fatty acids of the omega-3 group seems warranted. Clearly, a holistic approach including careful clinical and biological monitoring of the aging man and his prostate remains mandatory.

An evaluation of bicalutamide in the treatment of prostate cancer

Prostate cancer is a major health problem in men, causing significant morbidity and mortality. Although traditionally considered a disease of old age, improved diagnostic techniques have resulted in earlier diagnosis and many men are now treated while still physically and sexually active. Current therapies for prostate cancer, which include medical or surgical castration, have a significant impact on many aspects of quality of life. The non-steroidal antiandrogen bicalutamide (Casodex, AstraZeneca) has a favourable tolerability profile with demonstrated efficacy in several stages of prostate cancer and represents an alternative therapeutic strategy to castration. Mature survival data from men with previously untreated, locally-advanced disease reveal that bicalutamide monotherapy provides survival benefits that do not differ significantly from castration, while offering important advantages with respect to the maintenance of physical capacity and sexual interest. Recent data from a prospective randomised trial, the largest prostate cancer treatment study ever conducted, demonstrate that immediate therapy with bicalutamide (alone or as an adjuvant to therapy of curative intent) significantly reduces the risk of objective disease progression in patients with localised or locally-advanced prostate cancer. Antiandrogens are also used in combination with castration (combined androgen blockade) for advanced disease. Another large, randomised trial demonstrated that combined androgen blockade with bicalutamide is associated with a similar survival outcome to combined androgen blockade with flutamide and is better tolerated. The evidence reviewed demonstrates that bicalutamide currently has a favourable risk:benefit ratio in several stages of prostate cancer. The role of bicalutamide will be further defined by ongoing studies.

Antiandrogen monotherapy: indications and results

Many patients with prostate cancer for whom hormonal therapy is indicated are still physically and sexually active; quality of life is therefore a vital issue when considering treatment options. Traditional castration-based therapies, although effective, have implications with respect to quality of life, causing loss of libido, impotence, fatigue, and reduced bone mineral density. Monotherapy with a nonsteroidal antiandrogen is an attractive therapeutic alternative to castration, offering effective therapy with potential quality-of-life benefits. Of the available nonsteroidal antiandrogens, bicalutamide has been most extensively evaluated in the monotherapy setting. Mature combined data (56% mortality) from 2 large randomized studies show no statistically significant difference in overall survival between bicalutamide 150-mg monotherapy and castration in patients with locally advanced, nonmetastatic (stage M0) disease. Survival outcome in patients with metastatic (stage M1) disease (43% mortality) favored castration, although the difference in median survival between the groups was only 6 weeks. Bicalutamide 150-mg monotherapy was associated with significant advantages compared with castration, in terms of sexual interest and physical capacity, in patients with either M0 and M1 stage disease. Data from a small subgroup of patients with stage M0 disease suggest that bicalutamide may also reduce the risk of osteoporosis compared with castration. Long-term therapy with bicalutamide 150-mg monotherapy is generally well tolerated, with a predictable side-effect profile. The most common side effects are male breast pain and gynecomastia. Emerging evidence also supports the use of bicalutamide 150 mg, both as immediate monotherapy and as adjuvant therapy in early stage (localized or locally advanced) prostate cancer.

Antiandrogen monotherapy: a new form of treatment for patients with prostate cancer

Nonsteroidal antiandrogens are generally used in conjunction with castration as combined androgen blockade. However, the changing profile of patients with prostate cancer has made monotherapy with a nonsteroidal antiandrogen an attractive alternative therapeutic approach, offering potential quality-of-life benefits over conventional treatment modalities. Of available antiandrogens, monotherapy with bicalutamide has been most extensively evaluated. Combined data from 2 studies at a median follow-up time of 6.3 years revealed no statistically significant difference in overall survival between bicalutamide 150-mg monotherapy and castration in patients with nonmetastatic locally advanced disease. In patients with metastatic disease, there was a statistically significant difference (6 weeks) in overall survival in favor of castration. Bicalutamide monotherapy is associated with significant quality-of-life benefits (sexual interest and physical capacity), with preliminary data suggesting that the risk of osteoporosis may also be reduced by bicalutamide 150-mg monotherapy compared with castration. In general, bicalutamide is well tolerated, with a predictable adverse-effect profile. Breast pain (40%) and gynecomastia (49%) are the most common adverse events seen during monotherapy with this drug. In summary, the availability of bicalutamide 150-mg monotherapy broadens treatment options for men with locally advanced prostate cancer, offering a viable and attractive alternative to castration in this patient population. Ongoing studies will determine the role of bicalutamide in the treatment of localized disease.