Role of aminoglutethimide in male breast cancer

Management of Male Breast Cancer: The Journey so Far and Future Directions

Male breast cancer is now shown to be a unique entity and should be considered as a distinct disease. Given the relatively smaller number of cases, randomized controlled trials for treatment are extremely limited and majority of practices are derived from female breast cancer studies. This paper reviews available literature on surgical, radiation, and systemic therapies for male breast cancer, and discusses current practice recommendations.

Multicomponent Materials to Improve Solubility: Eutectics of Drug Aminoglutethimide

Here, we report the synthesis and experimental characterization of three drug-drug eutectic mixtures of drug aminoglutethimide (AMG) with caffeine (CAF), nicotinamide (NIC) and ethenzamide (ZMD). The eutectic mixtures i.e., AMG-CAF (1:0.4, molar ratio), AMG-NIC (1:1.9, molar ratio) and AMG-ZMD (1:1.4, molar ratio) demonstrate significant melting point depressions ranging from 99.2 to 127.2 °C compared to the melting point of the drug AMG (151 °C) and also show moderately higher aqueous solubilities than that of the AMG. The results presented include the determination of the binary melt phase diagrams and accompanying analytical characterization via X-ray powder diffraction, FT-IR spectroscopy and scanning electron microscopy.

Male breast carcinoma: radiotherapy contributed to favorable local control in two cases and related literature review

Male breast carcinoma (MBC) is rarely encountered in clinical practice. Due to its paucity, our knowledge of MBC only rely on small or single-institutional studies and sporadic cases. The current guidelines for MBC are extrapolated from its female counterparts Rudlowski (Breast Care (Basel) 3(3):183–189, 2008). Nowadays, MBC is actively studied and viewed as a potentially different entity on the aspects of etiology, biological behavior and prognosis. Thus, special treatment strategy guidelines should be established for MBC. Additionally, advance in the systemic chemotherapy and hormonal therapy also contribute to the local control. The indication of radiotherapy need to be clarified and over-treatment should be avoided. Here we present two cases of MBC in which radiotherapy help to sustain a satisfactory disease free survival. Our cases will provide valuable experience for identifying the role of radiotherapy in MBC.

Hormone Therapy for Breast Cancer in Men

Breast cancer in men is rare, but its incidence is increasing, in keeping with the aging population. The majority of breast cancers in men are estrogen receptor positive. There is a paucity of clinical trials to inform practice, and much has been extrapolated from breast cancer in women. Hormone therapy represents the mainstay of adjuvant and palliative therapy but may have contraindications or poor tolerability. We review the evidence for choice of hormone therapy in both the adjuvant and palliative setting in breast cancer in men.

New approaches in the management of male breast cancer

Male breast cancer (MBC) is a rare condition that accounts for 0.1% of all male cancers. Our current evidence base for treatment is derived from female breast cancer (FBC) patients. Risk factors for MBC include age, genetic predisposition, race, sex hormone exposure, and environmental factors. Most patients present later and with more advanced disease than comparable FBC patients. Tumors are likely to be estrogen receptor and progesterone receptor positive, with the most common histologic type being invasive ductal carcinoma. Triple assessment remains the criterion standard for diagnosis. Primary MBC is mostly managed initially by simple mastectomy, with the option of breast conserving surgery, which carries an increased risk of recurrence. Sentinel node biopsy is recommended as the initial procedure for staging the axilla. Reconstructive surgery focuses on achieving primary skin closure, and radiotherapy largely follows treatment protocols validated in FBC. We recommend chemotherapy for men with more advanced disease, in particular, those with estrogen receptor negative histology. MBC responds well to endocrine therapy, although it is associated with significant adverse effects. Third-generation aromatase inhibitors are promising but raise concerns due to their failure to prevent estrogen synthesis in the testes. Fulvestrant remains unproven as a therapy, and data on trastuzumab is equivocal with HER2 receptor expression and functionality unclear in MBC. In metastatic disease, drug-based hormonal manipulation remains a first-line therapy, followed by systemic chemotherapy for hormone-refractory disease. Prognosis for MBC has improved over the past 30 years, with survival affected by disease staging, histologic classification, and comorbidity.

Pharmacologic treatment of male breast cancer

Male breast cancer is an uncommon condition. It often occurs in settings in which there is an imbalance between androgens and oestrogens. Genetics plays an important role, as many cases are associated with mutations in BRCA2 or other genes. Male breast cancer occurs at an older age than female breast cancer and is frequently diagnosed at a later stage. Tumors are predominantly oestrogen and progesterone positive. Prognosis is approximately equivalent to that of breast cancer in females when matched for age, stage and hormonal receptors. The recommended treatment for male breast cancer is similar to that for breast cancer in postmenopausal females. However, the presence of androgens in males has a strong effect on the hormonal milieu and the ability of male patients to respond to hormonal agents. When pharmacologic treatment is required, tamoxifen is effective for first-line therapy. Other hormonal approaches such as orchiectomy, aromatase inhibitors and androgen ablation may be useful in later lines of therapy.

[Male breast cancer: a review of 52 cases collected at the Institute Bergonié (Bordeaux, France) from 1980 to 2004]

OBJECTIVES

To analyze the characteristics and to establish prognosis factors for 52 men suffering from breast cancer from 1980 to 2004.

PATIENTS AND METHODS

Men treated for breast cancer (invasive or in situ). A retrospective study analyzed clinical and histological characteristics, and treatment procedures. The probability of survival or recurrence was calculated using the Kaplan-Meier method. Prognostic factors were studied using the Log Rank test.

RESULTS

The mean age of our patients was 63.5 years old. In 73.1% of cases, subaerolar tumors were the initial symptoms, the average size was 30.31 mm. Among patients, 17 (32.7%) had T1, 19 (36.5%) T2, two (3.8%) T3 and 14 (26.9%) T4. The most represented histological type was the infiltrative ductal carcinoma (84.6%). The spread rate to axillary lymph nodes was 63.6%. The hormone dependency of these tumors was proven in 84.6% of cases. Overall survival rate were about 69% at five years and 32% at 10 years. The spread to lymph node and to derm, the clinical stage were significant factors influencing disease free survival. None of these factors had any significance regarding overall survival.

DISCUSSION AND CONCLUSION

Male breast cancer is a rare disease (about 1% of breast cancer) with a poor prognosis (32% 10 years disease free survival). An early diagnosis and better knowledge of the disease would certainly lead to improvement of prognosis.

Endocrine therapy for breast cancer: an overview

Endocrine therapy for breast cancer has been established in the adjuvant treatment for primary disease and in the treatment of advanced disease. The ER remains the best predictor of response although other factors exist and need to be identified. Pharmacological manipulation has been replacing ablative procedures. Tamoxifen used to be the most popular agent of choice and promising new agents include the pure anti-oestrogens and the third generation selective aromatase inhibitors. Ongoing and future studies will optimise treatment in established areas and will exploit its potential roles in preoperative use and chemoprevention.

Male breast cancer: a gender issue

The incidence of male breast cancer (MBC) is rising; however, mortality due to MBC has not changed, unlike female breast cancer. This lack of change is mostly attributable to a lack of major progress in the understanding and treatment of the disease. The treatment of MBC has been extrapolated from the knowledge of female breast cancer, despite the multiple differences in the pathogenesis, biology and genetics of these two disease entities, especially the differences with regard to the role of male hormones as well as estrogens in MBC compared with female disease. Although major advances in hormonal manipulation for the treatment of breast cancer are being developed, an improved understanding of the potential differences between male and female breast cancer is essential, as this would provide new opportunities for therapeutic intervention and probable improved outcome for MBC. This review aims at highlighting the major differences between male and female breast cancer with an emphasis on hormonal therapy, and discusses some of the recent advances in MBC.

Hormonal therapy for male breast cancer: A different approach for a different disease

Male breast cancer (MBC) is on the rise in the United States [Surveillance, Epidemiology, and End Results (SEER) Program () SEER Stat Database: Incidence-SEER 9 Regs Public-Use; November 2004 submission (1973-2002), National Cancer Institute, DCPPS, Surveillance Research Program, Cancer Statistics Branch, released April 2005, based on the November 2004 submission]; however mortality due to MBC has not changed unlike in its female counterpart [American Cancer Society: Cancer facts and figures 2005. Atlanta (GA): American Cancer Society; 2005]. The rarity of MBC has precluded major progress in the understanding and treatment of this disease. Treatment has often been extrapolated from female breast cancer (FBC) despite distinct clinicopathologic features between the two entities, especially with regards to the role of male hormones and estrogens in this disease. Also, it is uncertain if hormone receptor positive tumors carry the same prognostic implication in MBC as in the female disease. Hormonal therapy has been the mainstay of treatment in MBC with tamoxifen the front-line drug. The role of the newer generation aromatase inhibitors has not been well defined but they are being used in clinical practice for the treatment of MBC, based on accepted data for women with the disease. This commentary focuses on the major hormonal differences between male and female breast cancer that would suggest the need to explore different treatment strategies if significant advances are to be made in the understanding and treatment of this distinct disease.

Successful use of letrozole in male breast cancer: a case report and review of hormonal therapy for male breast cancer

Male breast cancer is an uncommon occurrence. Treatment of male breast cancer is typically extrapolated from data on the treatment of female breast cancer. Recently, aromatase inhibition has been proven as an effective therapy for female breast cancer, particularly in the setting of advanced cancers. The efficacy of aromatase inhibitors in males, however, has not been established. We report the successful treatment of a male with locally advanced breast cancer using the aromatase inhibitor letrozole.

Male breast cancer

Treatments for men with breast cancer are based largely on accepted regimens for women with the disease. Surgical treatment of the primary tumor should be a mastectomy. Lymph node assessment can be done by conventional axillary node dissection or, similar to selected women with small primary tumors, by sentinel node dissection. Decisions regarding adjuvant systemic treatment should be made on the same basis as for women. Axillary node status, tumor size, hormone receptor status, and the health of the patient are important considerations in determining what adjuvant treatment is offered. The role of radiation after mastectomy in men is not well defined, but radiation should be used in patients at high risk for local recurrence. For patients with metastatic disease, treatment is based on the hormone receptor status of the tumor and is similar to the treatment for women. Because most men with breast cancer have hormone receptor-positive disease, hormonal therapy is a mainstay of treatment and tamoxifen remains the front-line drug of choice, although the latest generation of aromatase inhibitors have supplanted tamoxifen as a first-line therapy for women. As a second-line hormonal therapy for men, orchiectomy or a luteinizing hormone-releasing hormone agonist with or without an antiandrogen are reasonable alternatives. There are no reports regarding the use of the antiestrogen fulvestrant in men, but its mechanism of action and efficacy in women suggest that it will be a useful agent in hormone receptor-positive male breast cancer. For men with hormone-resistant disease, palliative chemotherapy with the same agents used for treatment of women with breast cancer is appropriate.

Efficacy of anastrozole in male breast cancer

Metastatic breast carcinoma in men is usually responsive to hormonal therapy. Most ablative and additive hormonal therapies reported have had objective response rates in excess of 50%. Anastrozole has excellent antitumor activity in postmenopausal women, but no data exist on its efficacy in men. Medical records for all men with a diagnosis of breast cancer who were treated at M. D. Anderson from 1990 to 1999 were reviewed. Five male patients with metastatic breast cancer who were treated at M. D. Anderson with anastrozole were identified. We now report on these five cases.

Pharmacotherapy for male breast cancer

Breast cancer in males is uncommon, occurring at approxiamtely 1% of the rate of female breast cancer. Male breast carcinomas tend to be highly positive for hormone receptors, including oestrogen, progesterone and androgen receptors. Owing to this, hormone therapy is recommended as the primary treatment modality. Adjuvant therapy is recommended for male breast cancers with large size or positive axillary nodes. For metastatic disease, options for therapy include tamoxifen, orchiectomy, anti-androgens with or without luteinising hormone releasing hormone analogues or combination chemotherapy. The newer hormonal treatments, such as the selective aromatase inhibitors or novel antioestrogens, have not yet been well studied in male breast cancer but have potential for efficacy in this disease.

Carcinoma of the male breast: update 1994

In many ways, male and female breast cancers are similar, but do have some notable differences. Although the underlying etiology of male breast cancer may be partially due to hormonal or environmental changes, this disease is rare compared to female breast cancer. Most often, it presents as a painless lump, with estrogen receptor-positive infiltrating ductal carcinoma being the most common pathologic type. The main component of local therapy is either a radical or a modified radical mastectomy, with adjuvant chemotherapy proving useful. Estrogen receptor-positive tumors respond well to hormonal therapy. More research is needed in order to: (1) further characterize the molecular biological properties of male breast cancer tumors, (2) further investigate the role of adjuvant chemotherapy, and define successful regimens, and (3) determine optimal chemotherapy regimens in the treatment of metastatic disease. As this disease is a relatively rare condition, whenever possible, all patients should be allowed to participate in national cooperative group studies.

Advanced male breast cancer treatment with the LH-RH analogue buserelin alone or in combination with the antiandrogen flutamide

Ten men with advanced breast cancer were evaluated for response to treatment with the luteinizing hormone-releasing hormone (LH-RH) analogue, buserelin, alone or in combination with the antiandrogen, flutamide. One of five patients receiving buserelin as a single agent had a partial remission lasting 12 months, and with the addition of flutamide, this lasted over 24 additional months. Three patients had stable disease with a median duration of 6 months (range, two to 14). One patient had progressive disease. Of five patients receiving the combination of buserelin and flutamide from the beginning of therapy, four patients had a partial remission with a median duration of over 15 months (range, over five to 16). One patient's disease remained stable for 12 months. Major side effects were hot flushes, loss of libido, and impotence. Buserelin initiates a castration-like endocrine response and has potential in the treatment of men with disseminated breast cancer when used either alone or in combination with flutamide.

Aminoglutethimide and ketoconazole: historical perspectives and future prospects

Aminoglutethimide and ketoconazole, although originally developed as an anticonvulsant and antifungal agent respectively, have both been used to suppress steroid biosynthesis in patients with hormone-sensitive cancer. Aminoglutethimide inhibits several enzymes involved in the synthesis of corticosteroids as well as the aromatase enzyme which converts androgens to oestrogens. About one third of patients with breast cancer show objective improvement with aminoglutethimide, and it may also be of use in the treatment of adrenal carcinoma. However, its toxicity, and the need for concomitant cortisol replacement, severely limit its usefulness. Ketoconazole also inhibits several steroidogenic enzymes, notably C17,20-lyase, and has been used to treat carcinoma of the prostate. Again however, its toxicity and limited efficacy limit its value, although it may be useful in the treatment of certain endocrine conditions such as precocious puberty. Several aromatase inhibitors similar in structure to aminoglutethimide have been developed in an attempt to create more selective and efficient inhibitors. Some of these compounds have been tested in animals but none have as yet been subjected to clinical trials. Attempts to produce imidazole inhibitors of steroidogenesis are less advanced, although one compound (CGS 16949A) has been reported to be a more selective and potent aromatase inhibitor than aminoglutethimide. Selective and effective compounds could be of great value in the treatment of hormone-sensitive carcinoma.

Mechanisms of action of aminoglutethimide as endocrine therapy of breast cancer

During the last decade aminoglutethimide has been recognised as a valuable alternative in endocrine therapy for advanced breast cancer. Although some side effects do occur, most often these are initial effects which subside within a few weeks, and cessation of therapy is not usually indicated. Aminoglutethimide was originally introduced as an inhibitor of steroidogenesis in the adrenal cortex. It was soon recognised, however, that inhibition of the non-glandular aromatase, blocking the conversion of androgenic prohormones to oestrogens, was more important, resulting in decreased blood levels of oestrogens. In this review the role of aromatase inhibition as the only important aspect of the mechanism of action of aminoglutethimide is challenged. Evidence has accumulated during the last few years that aminoglutethimide is a most potent inducer of microsomal enzymes. In addition to the pharmacological implications this has (suggesting important interactions), it also points to the possibility that levels of oestrogens are decreased due to accelerated metabolism of these hormones. Based on new experimental data, and also clinical work with alternative aromatase inhibitors, it appears that the antitumour activity of aminoglutethimide may be due to both aromatase inhibition and accelerated metabolism of oestrogens. This seriously challenges the importance of aromatase inhibition alone as a strategy in endocrine therapy of breast cancer, and furthermore suggests that accelerated metabolism of key hormones is an alternative strategy to be explored.