Metastatic breast cancer in males. Assessment of endocrine therapy

The endocrinology of male breast cancer

Male breast cancer (MBC) is a rare disease but, as a result of epidemiological collaborations, there is now greater clarity concerning endocrine risk factors. The significant rise in global age-standardised mean BMI in men is likely to lead to increases in incidence of maturity-onset diabetes and MBC. The metabolic changes accompanying obesity decrease androgens and sex hormone-binding globulin (SHBG), thereby increasing available oestrogens. The higher rates of MBC in North and Equatorial Africa are largely due to liver damage from endemic bilharziasis and hepatitis B causing elevated oestradiol (E₂) levels from hepatic conversion of androgen. Klinefelter's syndrome (XXY) is associated with a 50-fold increase in incidence of MBC compared with XY males, and this is the most pronounced evidence for testicular malfunction amplifying risk. Delay in presentation means that up to 40% of cases have stage III or stage IV disease at diagnosis. No randomised controlled trials have been reported on endocrine treatment of advanced disease or adjuvant/neoadjuvant therapy following or preceding surgery. Tamoxifen is the most effective endocrine therapy, but side effects can lead to non-compliance in a substantial number of men. Aromatase inhibitors are less effective because they do not inhibit testicular oestrogen production. There is an urgent need for collaborative trials to provide an evidence base for the most effective endocrine and least toxic therapies for men with breast cancer.

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.

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.

Some Aspects of the Endocrine Profile and Management of Hormone‐Dependent Male Breast Cancer

The management of hormone-dependent male breast cancer is insufficiently understood by practicing oncologists. This article provides a review of the endocrine profile of male breast cancer, and outlines the differences between hormone-dependent female and male breast cancers. A concise review of the past, present, and possible future management of hormone-dependent male breast cancer is presented. For a better understanding of this disease, more information on the natural history and biological behaviors of patients with male breast cancer is needed. This could be accomplished by the development of a specific multi-institutional tumor registry and execution of prospective clinical trials.

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.

Carcinoma of the male breast: a review and recommendations for management

BACKGROUND

Male breast cancer is rare and experience of it in any single institution is limited. The aim of this study was to evaluate the presentation, management and outcome of male patients with breast cancer treated at Concord Repatriation General Hospital hospital over a 38-year period and to determine a best-practice protocol based on the results and a review of the literature.

METHODS

A total of 42 patients were retrospectively reviewed, pathology slides were re-examined and reclassified where necessary. Outcome was assessed and compared with results obtained from a literature review.

RESULTS

A trend towards less radical surgery has emerged. Overall 5-year survival was 50%, but, due to the late age at presentation, more than half the deaths were non-breast cancer related. One quarter of the patients presented with locally advanced or metastatic disease.

CONCLUSIONS

The presentation, diagnosis pathology and outcome of breast cancer are similar in men and women, although the disease occurs at a later age in men. Radical surgery is not required in order to gain local control, but knowledge of axillary node status is important in determining prognosis and the need for adjuvant therapy.

Male breast cancer: a review of the literature

Although breast cancer is uncommon in men, it can cause significant morbidity and mortality. The current review was undertaken to determine whether strategies applied for the evaluation and treatment of breast cancer in females are appropriate in male breast cancer. Male breast cancer has biological differences compared with female breast cancer, including a high prevalence in certain parts of Africa, a higher incidence of oestrogen receptor positivity and more aggressive clinical behaviour. It responds to hormonal manipulation and chemotherapy, but optimal treatment regimens in males are unknown. Male breast cancer remains an uncommon disease. Most of our current knowledge regarding its biology, natural history and treatment strategies has been extrapolated from its female counterpart. Much research is needed to further characterise the molecular biological properties of male breast tumours and their prognostic significance, and to devise treatment strategies, including optimal chemotherapy regimens.

A case of Mucinous Carcinoma of the Male Breast with Unusual Ultrasonographic Findings Mimicking Phyllodes Tumor

Mucinous carcinoma of the male breast is a rare histological type of cancer. We describe a 35-year-old male with mucinous carcinoma of the right breast. His breast mass enlarged subacutely, and became painful over a period of 2 months. Ultrasonography demonstrated echoes of a large multilocular cystic lesion with partially heterogenic internal echoes suggesting a phyllodes tumor. A modified radical mastectomy was performed, and histopathologic examination revealed mucin-producing solid or cribriform atypical cells with fibrous granulation tissue and hemosiderin deposition. The patient recovered uneventfully, and is still free of recurrence 30 months after his operation. The prognosis for male breast cancer can be improved by early diagnosis and appropriate multidisciplinary therapy.

Adjuvant radiotherapy for breast carcinoma in men: a 20-year clinical experience

Breast cancer in men is a rare malignancy. Current knowledge about its natural history and diagnostic and therapeutic management relies on reviews and few retrospective studies. From 1972 to 1993, 21 men were irradiated for operable primary (n = 17) or recurrent (n = 4) breast cancers at our institution. The mean age at initial diagnosis was 60 years (45-79 years). Tumor distribution by stage was: stage I (two), stage II (seven), stage III (six), stage IV (two), and unknown in four cases. Patients received radiotherapy to the chest-wall and ipsilateral lymph nodes (17) and to the axilla (seven). Additionally hormones (two) and chemotherapy (four) were applied in some cases. Follow-up ranged from 24 to 190 months (median, 53 months). At last follow-up (November 1994), nine patients were alive and eight without disease. The median overall survival of the whole group was 69 months (mean, 106 months). The 3-year (70%), 5-year (59%) and 10-year survival rates (46%) were consistent with literature data. Overall, relapse- and disease-free survival rates were better in patients with stage I/II than in those with stage III/IV disease. Univariate analysis revealed more favorable results for patients with negative axillary nodes, patients younger than 60 years, those with centrally localized tumors, and patients with a diagnostic delay of < 3 months, but the differences were not statistically significant. Six patients relapsed who had not received initial adjuvant radiotherapy to the site of their relapse. At last follow-up, 13 patients had distant metastases, and 12 of them are dead of the metastatic disease, which developed less frequently in stage I/II than in stage III/IV disease. Postoperative adjuvant radiotherapy is an essential part of the overall treatment strategy of advanced node-negative and node-positive cancer of the breast in men.

Breast cancer in men

Aside from its much lower frequency, breast cancer in men is remarkably similar to the disease in women. The cause remains equally obscure; the clinical presentation, pathology, and natural history are similar; and men are probably as curable in similar circumstances. Men are generally older and in more advanced stages than women when diagnosed, the tumors are located more often beneath the nipple and are more often responsive to hormonal therapy, but otherwise differences are negligible. Stage and axillary node status are strong prognostic indicators. Modified radical mastectomy has replaced radical mastectomy for surgical treatment of early states, and systemic adjuvant therapy appears to improve the prognosis for cases with involvement of lymph nodes.

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.

The management of male breast cancer in Nigerians

The outcome in 57 male patients with breast cancer has been analysed. Four patients with early disease had simple mastectomy (one case) and radical mastectomy (three cases). All four completed a 12-cycle cyclophosphamide/methotrexate/5-fluorouracil (CMF) course of chemotherapy. Two required orchiectomy after 23 and 38 months, respectively. Two patients were alive at 79 and 63 months. Fifty-three others with advanced disease had simple mastectomy (10 cases), radical mastectomy (38 cases) and no surgery (five cases), but only 33 completed chemotherapy and 11 were submitted to orchiectomy for recurrence after a mean interval of 19 months. Two patients were alive at 63 and 69 months, respectively. The overall survival rate was 7%. It is considered that in addition to late presentation (mean (SEM): 16.4 (2.1)) months and advanced disease (93%), ineffectiveness of the CMF regimen in male patients may have contributed to the poor survival rate in these Nigerian patients.

Male breast cancer

Male breast cancer is uncommon but important. The diagnosis is easily made by breast biopsy, and patients are presenting earlier in the course of the disease than in the past. Despite this, patients are often first seen with tumors that have metastasized to the axillary nodes, which markedly decreases the survival rate. Therapy of localized disease includes simple excision, modified radical mastectomy, and radical mastectomy, but there is no consensus for which operation is appropriate. Radiation therapy should be strongly considered in patients with metastases to the axillary nodes, but the role of adjuvant hormonal therapy or chemotherapy is unclear. For treatment of disseminated disease, tamoxifen seems to be replacing orchiectomy. The favorable response rate, especially in patients with estrogen-receptor-positive tumors, the lack of side effects, and the high level of patient acceptability make it an attractive therapeutic choice.

Tamoxifen. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic use

Tamoxifen, a non-steroidal antioestrogen, represents a significant advance in treatment of female breast cancer. In trials of tamoxifen as postsurgical adjuvant treatment of early breast cancer, disease-free survival is consistently prolonged, representing an enhanced quality of life in association with tamoxifen's favourable adverse effect profile. Moreover, overview analysis indicates a survival benefit of approximately 20% at 5 years for all women, most clearly evident in women over 50 years, while a survival benefit independent of menopausal, nodal or oestrogen receptor status has been demonstrated in some individual trials. Thus, for postmenopausal women, tamoxifen is clearly optimal adjuvant treatment, although the relative benefit of adjuvant chemotherapy in node-negative patients requires clarification. A survival benefit for women under 50 has not been clearly demonstrated in overview analysis, but is not precluded by these rather limited data, and adjuvant treatment of premenopausal women with tamoxifen may also warrant serious consideration. Response rates to tamoxifen in advanced breast cancer are around 30 to 35%, increasing with patient selection for oestrogen receptor positivity. Tamoxifen must be regarded as first-line endocrine treatment in postmenopausal women, and may represent an alternative to first-line ovarian ablation in premenopausal women. An emergent role in primary therapy of elderly and frail patients with operable disease is apparent. Tamoxifen is also of benefit following surgery in male breast cancer, and may have a role as first-line endocrine treatment. Tamoxifen also has a potential role in other hormone-sensitive malignancies such as pancreatic carcinoma, and in treatment of benign breast disease. Finally, tamoxifen has a place in treatment of male and female infertility. because of adverse effects is rarely necessary. The most frequent adverse effects are related to the drug's anti-oestrogenic activity, and include hot flushes, nausea and/or vomiting, vaginal bleeding or discharge, and menstrual disturbances in premenopausal patients. Thus, tamoxifen continues to play a major role in management of female breast cancer in both early and advanced stages of disease, with a place also in treatment of male breast cancer and of infertility.

Cancer of the male breast with prolonged survival

A retrospective review of patients suffering from male breast cancer was carried out at the Shands Teaching Hospital of the University of Florida. Thirteen evaluable cases were analyzed. Three patients were in Stage I, two patients in Stage II, none in Stage III, and eight in Stage IV. Two of the patients with Stage IV disease have had remarkably prolonged survivals of 194 months and 128 months. Such prolonged survivals are unusual. It is possible that the biology of male breast cancer is different from the female, and the disease should be approached more optimistically than it has in the past.

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.

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.

Male breast carcinoma. II. A study of the total material reported to the Swedish Cancer Registry 1958-1967 with respect to treatment, prognostic factors and survival

The complete material of male breast cancer, 166 cases, reported to the Swedish Cancer Registry in 1958-1967 is described and analyzed concerning different prognostic parameters, treatment methods and survival. Age at diagnosis, axillary lymph node status and tumour size all had significant prognostic importance in a multivariate analysis with axillary lymph node status as the strongest factor. Histologic malignancy grade was strongly correlated to axillary lymph node status and tumour size and thus to prognosis, but did not seem to be an independent prognostic factor. The primary treatment methods were quite heterogeneous and were obviously influenced by both age of the patient and clinical tumour status. No significant correlation was found between type of primary treatment and survival, but due to the retrospective nature of the study no definite conclusion could be drawn. Radical mastectomy seemed, however, to give fewer loco-regional recurrences than both modified radical mastectomy and simple mastectomy. Very few patients in the present series had received radiation therapy in adequate doses. The material gave some indications that orchiectomy might prolong survival in patients with recurrent or generalized disease.

Role of aminoglutethimide in male breast cancer

Five men with advanced breast cancer were treated with aminoglutethimide (AG) plus replacement dose hydrocortisone. None of the 4 patients with intact testes responded, although 3 did so subsequently to tamoxifen. The previously orchidectomized patient responded to aminoglutethimide for 14 months. Oestrone and oestradiol were suppressed by AG in all patients, but not to the levels achieved by orchidectomy. AG produced substantial further oestrogen suppression in the orchidectomized patient and should only be used after orchidectomy.