Aromatase inhibitors and male breast cancer

Assessment of the Aromatase Inhibitory Activity of Ma-Huang-Tang (MHT) and Its Active Compounds

Aromatase, a cytochrome P450 enzyme that converts androgens into estrogens, is an important drug target for hormone-dependent diseases. The purpose of this study was to elucidate the aromatase inhibitory effects of Ma-Huang-Tang (MHT), a traditional Korean herbal medicine prescription, and to identify its active ingredients. In this study, the inhibitory effect of MHT on aromatase activity was observed using dibenzylfluorescein (DBF) and KGN cells, and the dose-dependent effect of MHT was verified (IC₅₀ values of 251 μg/mL and 246 μg/mL as determined by the two methods, respectively). Furthermore, among the six herbal medicines that constitute MHT, Ephedrae Herba, Cinnamomi Ramulus, and Glycyrrhizae Radix et Rhizoma showed the most potent inhibition of aromatase activity. Furthermore, upon identification of the active MHT compounds, three markers from Glycyrrhizae Radix et Rhizoma, liquiritin (5), liquiritin apioside (6), and liquiritigenin (7), were verified (IC₅₀ values of 530 μM, 508 μM, and 1.611 mM and 499 μM, 522 μM, and 1.41 mM as determined by the two methods, respectively). In addition, their contents were confirmed to be 15.58, 19.80, and 2.22 mg/g, respectively, by HPLC/DAD analysis. These results indicate that the aromatase inhibitory effect of MHT results from the synergistic action of its active components and that MHT has potential as a preventive agent against aromatase activity.

Aromatase: Contributions to Physiology and Disease in Women and Men

Aromatase (estrogen synthetase; EC 1.14.14.1) catalyzes the demethylation of androgens' carbon 19, producing phenolic 18-carbon estrogens. Aromatase is most widely known for its roles in reproduction and reproductive system diseases, and as a target for inhibitor therapy in estrogen-sensitive diseases including cancer, endometriosis, and leiomyoma (141, 143). However, all tissues contain estrogen receptor-expressing cells, the majority of genes have a complete or partial estrogen response element that regulates their expression (61), and there are plentiful nonreceptor effects of estrogens (79); therefore, the effect of aromatase through the provision of estrogen is almost universal in terms of health and disease. This review will provide a brief but comprehensive overview of the enzyme, its role in steroidogenesis, the problems that arise with its functional mutations and mishaps, the roles in human physiology of aromatase and its product estrogens, its current clinical roles, and the effects of aromatase inhibitors. While much of the story is that of the consequences of the formation of its product estrogens, we also will address alternative enzymatic roles of aromatase as a demethylase or nonenzymatic actions of this versatile molecule. Although this short review is meant to be thorough, it is by no means exhaustive; rather, it is meant to reflect the cutting-edge, exciting properties and possibilities of this ancient enzyme and its products.

Everolimus and exemestane in long survival hormone receptor positive male breast cancer: case report

Background

Male breast cancer is a rare event, accounting for approximately 1% of all breast carcinomas. Although men with breast cancer had poorer survival when compared with women, data on prognosis principally derive from retrospective studies and from extrapolation of female breast cancer series. We reported the case of a very long survival patient.

Case presentation

A caucasian 42-year-old man underwent radical mastectomy with axillary dissection for breast cancer in 1993. Pathologic stage was pT4pN0M0 infiltrating ductal carcinoma of right breast without lymph nodes metastases. Biological characterization was not available. He received adjuvant treatment with chemotherapy, six cycles of cyclophosphamide, methotrexate and fluorouracil, then endocrine therapy with tamoxifen for 5 years and complementary radiotherapy. Then he began clinical-instrumental follow up. In May 1996, a computed tomography scan showed multiple lung metastases. Hereafter he received several oncologic treatment including seven chemotherapy and five endocrine therapy lines with two re-challenge of endocrine therapy. In October 2007 further lung progression was showed and a biopsy was performed to characterize the disease. Histological examination confirmed breast cancer metastases, immunohistochemistry showed positive staining for estrogen receptor, negative for progesterone receptor and human epithelial growth factor receptor 2, proliferative index was 21%. In April 2013, bone disease progression was evident and he received radiant treatment to sacral spine. In May 2014 an off-label treatment with exemestane and everolimus combination was approved by Ethics Committee of the Marche Region. The patient received treatment for 3 months with evident clinical benefit to subcutaneous lesions of the chest wall that were not visible nor palpable on physical examination after 1 month of treatment.

Conclusion

That is the case of long survival male breast cancer patient with luminal B subtype and no BRCA mutations. He achieved higher progression free survival with endocrine therapy creating the rationale for last line treatment with everolimus and exemestane combination. Attending conclusive results from ongoing studies, everolimus and exemestane should not be used routinely in male metastatic breast cancer patients, but taking into account for selected cases. At the best of our knowledge, this is the first case of male beast cancer treated with exemestane and everolimus combination.

Male breast cancer is not congruent with the female disease

It has become customary to extrapolate from the results of treatment trials for female breastcancer and apply them to males with the disease. In the absence of results from national and international randomised trials for male breast cancer (MBC) this appears superficially to be an appropriate response. Closer examination of available data reveals that aspects of the aetiology and treatment of MBC do not fit the simplistic model that men usually have endocrine sensitive tumours which behave like those in postmenopausal women. Most females and males with breast cancer have none of the recognised risk factors, indicating the gaps in our knowledge of the epidemiology of this disease. Several studies have compared epidemiological risk factors for MBC and female breast cancer (FBC) but many have been blighted by small numbers. In comparison with FBC there is a larger proportion of BRCA2 tumours, (occurring in 10% of MBC), and underrepresentation of BRCA1 tumours (found in only 1%), suggesting significant differences in the genetic aetiology of MBC and FBC. Genome-wide association studies in FBC reported single nucleotide polymorphisms (SNPs) in 12 novel independent loci were consistently associated with disease but for MBC 2 SNPs had a significantly increased risk. Molecular profiles of matched cancers in males and females showed a gender-associated modulation of major processes including energy metabolism, regulation of translation, matrix remodelling and immune recruitment. Immunohistochemistry for kinase inhibitor proteins (KIPs) p27Kip1 and p21Waf1 indicate a significant difference in the immunostaining of tumours from male patients compared with females. MBC is almost always estrogen receptor positive (ER+ve) and so systemic treatment is usually endocrine. With evidence in FBC that aromatase inhibitors are more effective than tamoxifen in the postmenopausal it was seemingly logical that the same would be true for MBC. Results however suggest less efficacy with AIs and an increase in risk of mortality compared to tamoxifen. The overall survival in male breast cancer was significantly better after adjuvant treatment with tamoxifen compared to an aromatase inhibitor. These important biological differences point the way to the development of new therapies for MBC based on differences rather than similarities with FBC.

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.

Aromatase inhibitors for metastatic male breast cancer: molecular, endocrine, and clinical considerations

Male breast cancer is a rare condition. Aromatase inhibitors are widely used for treating metastatic male breast cancer patients. In this setting, their use is not substantiated by prospective clinical trials, but is rather driven by similarities supposedly existing with breast cancer in postmenopausal women. This oversimplified approach was questioned by studies addressing the molecular and endocrine roots of the disease. In this manuscript, we discuss relevant aspects of the current use of aromatase inhibitors in metastatic male breast cancer in light of the most updated evidence on the molecular landscape of the disease and the specific changes in the hormonal background occurring with aging. We further point to strategies for blocking multiple hormonal pathway nodes with the goal of improving their therapeutic potential. We searched PubMed from its inception until March 2014 for relevant literature on the use of aromatase inhibitors in metastatic male breast cancer. Selected terms were combined and used both as medical headings and text words. The reference list of the suitable manuscripts was inspected for further publications. Aromatase inhibitors represent the mainstay of treatment in the metastatic setting. Yet, efforts aimed at sharpening the therapeutic potential of aromatase inhibitors still pose a challenge due to the paucity of data. The choice of dual hormonal (or sequential) therapy combining aromatase inhibitors with a GnRH analogue may represent a valid alterative, particularly if informed by cancer- and patient-related features including molecular, endocrine, and clinic characteristics.

Aromatase inhibitors with or without gonadotropin-releasing hormone analogue in metastatic male breast cancer: a case series

Background:

Data regarding the safety and effectiveness of aromatase inhibitors (AIs) as monotherapy or combined with gonadotropin-releasing hormone (GnRH) analogue in male breast cancer are scarce.

Methods:

In this retrospective chart review, cases of male breast cancer patients treated with AIs with or without a GnRH analogue were evaluated.

Results:

Twenty-three men were included into this case series. Aromatase inhibitors in combination with or without a GnRH analogue were given as first-line therapy in 60.9% and as second-line therapy in 39.1% of patients, respectively. All patients had visceral metastases, whereas in five of them bone lesions coexisted. In all cases AIs were tolerated well, and no case of grade 3 and 4 adverse events was reported. A partial response was observed in 26.1% of patients and stable disease in 56.5%. Median overall survival (OS) was 39 months and median progression-free survival (PFS) was 13 months. Regarding OS and PFS, no significant effects of GnRH analogue co-administration or type of AI were noted.

Conclusion:

Our study shows that AIs with or without GnRH analogues may represent an effective and safe treatment option for hormone-receptor positive, pretreated, metastatic, male breast cancer patients.

Male breast carcinoma: increased awareness needed

Male breast carcinoma is a rare condition. Few male breast cancer-specific epidemiological or clinical trial data are available - our understanding of male breast cancer thus comes from studies of female breast cancer, painting an inaccurate picture when it comes to determining contributing factors. Clinicians report an increase in diagnoses of male breast cancer but this has not been formally reported. We therefore undertook a review of data obtained from four western nations: England, Scotland, Canada and Australia. When adjusted for age, this review clearly showed an increase in the incidence of male breast cancer over a 15-year period. Reasons for the increased incidence are discussed in the context of suggested risk factors such as BRCA2 and lifestyle changes over the past few decades. The clinical management of male breast carcinoma is considered, in particular the potential role of aromatase inhibitors and fulvestrant and targeting pathways involving prolactin and androgen receptor.

Male breast cancer

Male breast cancer (MBC) is a rare disease. However, as global populace ages, there is a trend to MBC increasing. Although aetiology is still unclear, constitutional, environmental, hormonal (abnormalities in estrogen/androgen balance) and genetic (positive family history, Klinefelter syndrome, mutations in BRCA1 and specially BRCA2) risk factors are already known. Clinic manifestation is painless hard and fixed nodule in the subareolar region in 75% of cases, with nipple commitment earlier than in women. Breast cancer has similar prognostic factors in males and females, among which axillary adenopathy (present in 40-55% cases) is the most important one. Although mammography, ultrasonography and scintigraphy can be useful tools in diagnosis; clinical assessment, along with a confirmatory biopsy, remains the main step in the evaluation of men with breast lesions. Infiltrating ductal carcinoma is the most frequent histological type. The established standard of care is modified radical mastectomy followed by tamoxifen for endocrine-responsive positive disease, although other options are being explored. While similarities between breast cancer in males and females exist, it is not appropriate to extrapolate data from female disease to the treatment of male. There is a need for specific multi-institutional trials to better understanding of clinicopathologic features and establishment of optimal therapy for this disease.

Influence of Sex Hormones on Cancer Progression

To review the influence of sex hormones on the progression of breast, prostate, gynecologic, and colorectal cancer. The literature was reviewed in an informal manner utilizing the authors' prior knowledge to collate the current evidence for the involvement of sex hormones, particularly estrogens and androgens in the progression of a range of hormonally responsive cancers. In particular, the effect of treatment involving hormone withdrawal treatment was considered strong evidence for involvement. The impact of basal levels of endogenous steroids was considered. Data from clinical trials indicate the efficacy of therapeutic interventions that result in ablation or antagonism of host steroids for a range of cancers. Demonstration of the correlation of the completeness of withdrawal with clinical outcome together with direct evidence of progression from studies looking at the influence of tissue and circulating levels of sex hormones more recently in conjunction with gene expression profiles all provide compelling evidence for the involvement of steroids in the progression of disease. The involvement of steroids in the progression of cancer in hormone-sensitive tissues is well established and an important target for therapy.

Male breast cancer: a survey at the Helsinki University Central Hospital during 1981-2006

BACKGROUND

The purpose was to analyze the behavior of male breast cancer.

METHODS

Fifty-eight male breast cancer patients were treated at the HUCH during 1981-2006. Data on risk factors, tumor characteristics, clinical presentation, treatment and survival were obtained by chart review.

RESULTS

Presentation occurred at a median age of 63 years, most often due to a self-detected lump. The median size of the primary tumor was 1.8 cm and 14% were T4 tumors. Forty-seven percent had lymph node metastases and 4% distant metastases at diagnosis. Ductal carcinoma was the most common tumor type. All tumors with known receptor status were positive for estrogen receptor (ER) and 79% for progesterone receptor (PgR). Her-2 overexpression was found in 2/19 patients (11%). A family history of breast cancer, obesity, high alcohol intake and liver cirrhosis were the most often seen risk factors. Nineteen percent had one or two other malignancies, the most common second malignancy being prostate cancer in 7%. Ninety-seven percent were operated by mastectomy and 90% by axillary evacuation while sentinel node biopsy alone was done only in 7%. Sixty percent of the patients received radiotherapy, 64% adjuvant hormonal treatment, 20% adjuvant chemotherapy, and 2% adjuvant trastuzumab. Fourteen patients (25%) experienced a relapse of which 60% were distant, bone being the most common site. During follow-up 21 patients (37%) died, of whom nine of breast cancer and 12 due to other causes. The 5-year overall survival (OS) was 75%.

CONCLUSIONS

Male breast cancer behaves and is today treated in many respects like postmenopausal breast cancer. However, due to rudimentary breast tissue the symptoms, diagnosis and especially a higher amount of T4 tumors differ from that of females. Also the risk factor profile and histologic subgroups seem different. The 5-year OS of 75% is clearly higher than 44% reported at our institution in 1982.

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.

Male breast cancer: is the scenario changing

Background

The overall incidence of male breast cancer is around 1% of all breast cancers and is on the rise. In this review we aim to present various aspects of male breast cancer with particular emphasis on incidence, risk factors, patho-physiology, treatment, prognostic factors, and outcome.

Methods

Information on all aspects of male breast cancer was gathered from available relevant literature on male breast cancer from the MEDLINE database over the past 32 years from 1975 to 2007. Various reported studies were scrutinized for emerging evidence. Incidence data were also obtained from the IARC, Cancer Mondial database.

Conclusion

There is a scenario of rising incidence, particularly in urban US, Canada and UK. Even though more data on risk factors is emerging about this disease, more multi-institutional efforts to pool data with large randomized trials to show treatment and survival benefits are needed to support the existing vast emerging knowledge about the disease.