Epidemiology of male breast cancer

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.

Bilateral male breast cancer with male potential hypogonadism

Background

Male breast cancer is a comparatively rare disease, and simultaneous bilateral male breast cancer is considered to be an extremely rare event. Risk factors are said to be genetic factors and hormonal abnormalities due to obesity or testicular diseases.

Case presentation

The patient was a 47-year-old Japanese male. His family had no history of female breast cancer. This patient also had hypospadias and hormonal examination indicated the presence of primary testicular potential hypogonadism, and these hormonal abnormalities seemed to be present since childhood or the fetal period. The bilateral breast cancer developed in this man at a comparatively young age, and histopathological studies of multiple sections showed that there was almost no normal epithelial cell in the ducts, while the ducts were almost completely filled with breast cancer cells.

Conclusion

It is thought that male breast cancer is caused by an imbalance between estrogen and testosterone. We cannot rule out the possibility that the breast cancer developed due to the effect of the slight elevation of estrogen over a long period of time, but the actual causative factors in this patient were unable to be definitively identified. In the future, we hope to further elucidate the causes of male breast cancer.

Comparative epidemiology of breast cancer among men and women in the US, 1996 to 2000

OBJECTIVE

Few investigations of breast cancer among men have been conducted because of the relative rarity of this malignancy. The objective of this analysis was to compare the demographic, pathological, and clinical features of breast cancer among men and women.

METHODS

Breast cancer among 6379 men and 744,275 women was identified through 34 US population-based registries in the US during the period 1996 to 2000. These registries were estimated to represent 69% of the US population. Age-adjusted incidence rates (AAIR) were calculated per million population using counts derived from the 2000 US census.

RESULTS

The AAIR of breast cancer among men (16.6) was substantially lower than the incidence among women (1557.7). Rates of breast cancer among black men were higher than among white and Asian-Pacific Island men, in contrast to women among whom rates in whites exceeded those among other ethnic groups. Similar to women, breast cancer rates among non-Hispanic men were 50% greater than among Hispanic men. Ductal cancer was the most common histologic type diagnosed in both sexes. The incidence of lobular cancer was rare in men, but Paget's disease and papillary carcinoma occurred with lower relative frequency in women than in men. Lobular breast cancers were less common among black men and women than among other ethnic groups. In situ breast cancer was diagnosed in 10.8% of men and 16.2% of women. Localized breast cancer was the most common stage at diagnosis in both sexes and all ethnic groups, although women were more likely than men to be diagnosed at a localized stage. Cancer was 10% more likely to be diagnosed in the left breast than the right breast among men compared to 4% in women.

CONCLUSIONS

In spite of the rare incidence of breast cancer in men, the descriptive epidemiology of this malignancy is surprisingly similar to that in women. An explanation for the greater relative incidence of breast cancer in black men is a research challenge.

Male Breast Cancer Incidence Among Atomic Bomb Survivors

To learn more about the role of ionizing radiation in the development of male breast cancer, we evaluated male breast cancer incidence among 45 880 male members of the Life Span Study cohort of Japanese atomic bomb survivors. Male breast cancers, diagnosed between January 1, 1958, and December 31, 1998, were identified through the Hiroshima and Nagasaki Tumor Registries. Nine male breast cancers were diagnosed among exposed Life Span Study members (crude rate = 1.8 per 100,000 person-years), and three were diagnosed among nonexposed cohort members (crude rate = 0.5 per 100,000 person-years). A statistically significant dose-response relation was observed (excess relative risk per sievert = 8, 95% confidence interval = 0.8 to 48; P = .01). Our finding of a statistically significant association between ionizing radiation and male breast cancer incidence adds to the very limited information that shows an association between radiation exposure and an increased risk of male breast cancer.

Sentinel node biopsy in male breast cancer

OBJECTIVE

Male breast cancer is a rare disease and axillary status is the most important prognostic indicator. Lymphoscintigraphy associated with gamma-probe guided surgery has been proved to reliably detect sentinel nodes in female patients with breast cancer. This study evaluates the feasibility of the surgical identification of sentinel node by using lymphoscintigraphy and a gamma-detecting probe in male patients, in order to select subjects who would be suitable for complete axillary lymphadenectomy.

METHODS

Colloid human albumin labelled with 99Tc was administered to 18 male patients with breast cancer and clinically negative axillary lymph nodes. Lymphoscintigraphy was performed the day before surgery. An intraoperative gamma-detecting probe was used to identify sentinel nodes during surgery.

RESULTS

Lymphoscintigraphy and biopsy of the sentinel node were successful in all cases. A total of 20 sentinel nodes were removed. Pathological examinations showed 11 infiltrating ductal carcinomas, two intraductal carcinomas and five intracystic papillary carcinomas. Six patients (33%) had positive sentinel node (micrometastases were found in three patients). These patients underwent axillary dissection; in five of them (83%) the sentinel node was the only positive node. Twelve patients (67%) showed negative sentinel nodes; in all of them no further surgical treatments were planned.

CONCLUSIONS

As in women, lymphoscintigraphy and sentinel node biopsy under the guidance of a gamma-detecting probe proved to be an easy method for the detection of sentinel nodes in male breast carcinoma. In male patients with early stage cancer, sentinel node biopsy might represent the standard surgical procedure in order to avoid unnecessary morbidity after surgery, preserving accurate staging of the disease in the axilla.

Frequent amplification and overexpression of CCND1 in male breast cancer

Genetic events underlying the pathogenesis of breast cancer have been studied extensively and several clinically significant markers have been identified. For example, amplification and overexpression of the ERBB2 oncogene is associated with poor prognosis in breast cancer and ERBB2 serves as a target for antibody-based therapy. Current knowledge on the pathogenesis of male breast cancer (MBC) is limited. The purpose of our study was to investigate the potential relevance of a series of genes known to be amplified in female breast cancer (FBC) in a the development and pathogenesis of MBC. To this end, we applied fluorescence in situ hybridization and immunohistochemistry to the analysis of 128 breast tumors from males. Amplification of ERBB2, MYC, PPM1D and ZNF217 was detected rarely (1-2% of tumors) indicating a considerably lower amplification frequency than in FBC. CCND1 amplification was observed in 12% of cases, being in good concordance with findings from FBC. In addition, CCND1 overexpression was detected in 63% of tumors and was associated with ER positivity (p < 0.0001). Our results indicate distinct differences in the genetic basis of MBC and FBC and suggest that marked differences exist in the pathogenesis of these diseases. The lack of ERBB2 involvement was especially unexpected and implies that ERBB2-targeted therapies are unlikely to be beneficial in MBC. Furthermore, the high frequency of hormone receptor positivity and the association between ER positivity and CCND1 overexpression supports the notion that hormonal regulation is likely to be essential for the development of MBC.

Is Male Breast Cancer Similar or Different than Female Breast Cancer?

OBJECTIVE

To determine if male breast carcinogenesis was similar to its more common female counterpart, we compared incidence patterns among men and women with breast cancer.

METHODS

Breast cancer records were obtained from the SEER database. Women were stratified by age < 50 and > or = 50 years to simulate premenopausal and postmenopausal breast cancer.

RESULTS

Age-adjusted incidence trends were stable among men but increased among women. Male to female breast cancer ratio was higher for blacks than for whites. Favorable prognostic factors reflective of tumor biology (nuclear grade and hormone receptor expression) were more common for men and postmenopausal women than for premenopausal women. For example, low nuclear grade, estrogen and progesterone receptor-positive expression were more common among men and postmenopausal women than among premenopausal women. The age-specific incidence rate curve for men increased steadily for all ages with a constant slope. On the other hand, age-specific rates for women increased rapidly until age 50 years then rose at a slower rate for postmenopausal women. Age-frequency distribution for male breast cancer was unimodal, with peak incidence at age 71 years. Age-frequency distribution for women was bimodal with early-onset and late-onset incidence at 52 and 71 years, respectively.

CONCLUSIONS

Gender-specific incidence trends differed, most likely reflective of female-related changes in surveillance and/or reproductive risk factors. On the other hand, similar prognostic factor profiles reflective of tumor biology, age-specific incidence rate patterns, and age-frequency distributions suggested that male breast cancer was more like postmenopausal than premenopausal female breast cancer.