Similarities and differences in the characteristics and primary treatment of breast cancer in men and women - a population based study (Sweden)

A systematic literature review of the management, oncological outcomes and psychosocial implications of male breast cancer

BACKGROUND

Although male breast cancer (MBC) is a rare disease, accounting for <1% of all breast cancers, it has significant oncological, survival and psychosocial implications for patients. The aim of this study is to assess the latest literature in the diagnosis, management, oncological outcomes, and psychosocial impact of MBC.

METHODS

A systematic literature review was conducted using the PRISMA guidelines (Moher et al., 2009) [1] to explore the management of MBC, with particular focus on investigative imaging, surgical management, oncological outcomes, survival, genetic screening and psychosocial effects. Electronic databases were searched for randomised control trials, cohort studies and case series involving more than 10 patients. Imaging and surgical techniques, local and distant disease recurrence, survival, genetic screening and psychosocial implications in the setting of MBC were assessed.

RESULTS

The search criteria identified 199 articles, of which 59 met the inclusion criteria. This included 39,529 patients, with a mean age of 64.5 years (55-71), and a mean follow-up of 66.3 months (26.2-115). Mastectomy remains the most frequently used surgical technique, with an average of 89.6%. Loco-regional and distant recurrence rate was 10.1% and 21.4% respectively. Disease-free survival (DFS) at 5 and 10 years was 66.8% and 54.5% respectively. Disease-specific survival (DSS) at 5 and 10 years was 87.1% and 67.1% respectively. Overall survival (OS) at 5 and 10 years was 72.7% and 50.7% respectively. Genetic screening was conducted in 38.6% of patients of which 4.8% and 15.8% were found to be BRCA1 and BRCA2 carriers respectively. Psychosocial studies were conducted mainly using questionnaire and interview-based methodology focusing primarily on awareness of breast cancer in men, support available and impact on gender identity.

CONCLUSIONS

This review demonstrates that men present with later stage disease with subsequent impact on survival outcomes. There remains a paucity of high-level evidence and prospective studies are required. There is a need for increasing awareness amongst the public and health care professionals in order to improve outcomes and reduce stigma associated with MBC.

Development and validation of a nomogram to predict survival for advanced male breast cancer

Male breast cancer is a rare disease. Many experiences of male breast cancer were derived of female breast cancer. However, there are huge differences between two groups. We conducted this study to find a reliable prognostic model for advanced male breast cancer. The cohort was selected from the Surveillance, Epidemiology, and End Results database. The enrolled patients were randomly divided into training and validation group. The univariate and multivariate analyses were used for prognostic assessment and a nomogram was built. Calibration curves and concordance index were compiled to determine predictive and discriminatory capacity. The time-dependent receiver operating curves and the decision curve analysis was used to verify the model's ability. Two hundred and eighty individuals were enrolled. The cumulative rates of 1-, 3- and 5-year overall survival (OS) rates were 98.6%, 72% and 57.9%. The C-indexes for OS were 0.835 (95%CI, 0.777-0.893) in the training group and 0.765 (95%CI, 0.668-0.862) in the validation group. The calibration curves confirmed the consistency of the nomogram both in the training and validation group. The time-dependent receiver operating curves and decision curve analysis demonstrated that the nomogram had better prediction capacity than TNM stage system for advanced male breast cancer. The nomogram we built was a reliable and solid predictive model.

Investigating men's motivations to engage in genetic screening for BRCA1 and BRCA2 mutations

BRCA1 and BRCA2 mutations are associated with an increased risk of developing numerous cancers, including breast, ovarian, pancreatic, melanoma and prostate cancer. Men face BRCA-related cancer risks as women do. However, there is considerably less research on the psychological determinants of men engaging in BRCA1/2-related cancer prevention compared to women. The present research aimed to study the determinants of men’s motivations to engage in genetic screening for BRCA1 and BRCA2 through the lens of the Health Action Process Approach. One hundred and twenty-five men (mean age = 58.53 y/o, SD = 10.37) completed an online survey. The intention to undergo genetic screening for BRCA1/2 mutations in men was significantly and positively associated with self-efficacy and risk perception. Moreover, having offspring positively affected intention as well. The relationships between intention (and planning) and positive outcome expectancies, age, and family history of breast-related cancer were not statistically significant. Most information on BRCA1 and BRCA2 mutations is tailored to women due to the availability of effective surgical risk reduction procedures for women’s breast and ovarian cancer. Future research should focus on the best methods of communicating informed decision-making for men facing the risk of such mutations.

Development and Validation of a Nomogram for Predicting Survival in Male Patients With Breast Cancer

Male breast cancer (MBC) is rare, and most patients are diagnosed at an advanced stage. We aimed to develop a reliable nomogram to predict breast cancer-specific survival (BCSS) for MBC patients, thus helping clinical diagnosis and treatment. Based on data from the Surveillance, Epidemiology, and End Results (SEER) database, 2,451 patients diagnosed with MBC from 2010 to 2015 were selected for this study. They were randomly assigned to either a training cohort (n = 1715) or a validation cohort (n = 736). The Multivariate Cox proportional hazards regression analysis was used to determine the independent prognostic factors, which were then utilized to build a nomogram for predicting 3- and 5-year BCSS. The discrimination and calibration of the new model was evaluated using the Concordance index (C-index) and calibration curves, while its accuracy and benefits were assessed by comparing it to the traditional AJCC staging system using the net reclassification improvement (NRI), the integrated discrimination improvement (IDI), and the decision curve analysis (DCA). Multivariate models revealed that age, AJCC stage, ER status, PR status, and surgery all showed a significant association with BCSS. A nomogram based on these variables was constructed to predict survival in MBC patients. Compared to the AJCC stage, the C-index (training group: 0.840 vs. 0.775, validation group: 0.818 vs. 0.768), the areas under the receiver operating characteristic curve of the training set (3-year AUC: 0.852 vs. 0.778, 5-year AUC: 0.841 vs. 0.774) and the validation set (3-year AUC: 0.778 vs. 0.752, 5-year AUC: 0.852 vs. 0.794), and the calibration plots of this model all exhibited better performance. Additionally, the NRI and IDI confirmed that the nomogram was a great prognosis tool. Finally, the 3- and 5-year DCA curves yielded larger net benefits than the traditional AJCC stage. In conclusion, we have successfully established an effective nomogram to predict BCSS in MBC patients, which can assist clinicians in determining the appropriate therapy strategies for individual male patients.

Ghrelin expression is associated with a favorable outcome in male breast cancer

Ghrelin and obestatin are two gastrointestinal peptides, derived from a common precursor. Expression of both peptides have been found in breast cancer tissue and ghrelin has been associated with breast cancer development. Ghrelin expression is associated with longer survival in women diagnosed with invasive and node negative breast cancer. The clinical implications of the peptide expression in male breast cancer are unclear. The aim of this study was to investigate the role and potential clinical value of ghrelin and obestatin in male breast cancer. A tissue microarray of invasive male breast cancer specimens from 197 patients was immunostained with antibodies versus the two peptides. The expression of the peptides was correlated to previously known prognostic factors in breast cancer and to the outcome. No strong correlations were found between ghrelin or obestatin expression and other known prognostic factors. Only ghrelin expression was statistically significantly correlated to breast cancer-specific survival (HR 0.39, 95% CI 0.18–0.83) in univariate analyses and in multivariate models, adjusted for tumor size and node status (HR 0.38, 95% CI 0.17–0.87). HR for obestatin was 0.38 (95% CI 0.11–1.24). Ghrelin is a potential prognostic factor for breast cancer death in male breast cancer. Patients with tumors expressing ghrelin have a 2.5-fold lower risk for breast cancer death than those lacking ghrelin expression. Drugs targeting ghrelin are currently being investigated in clinical studies treating metabolic or nutritional disorders. Ghrelin should be further evaluated in forthcoming studies as a prognostic marker with the aim to be included in decision algorithms.

Survival Comparisons Between Early Male and Female Breast Cancer Patients

We aimed to compare the overall survival (OS) and standardized mortality rate (SMR) of the male breast cancer (MBC) with female breast cancer (FBC) after propensity score matching. Based on the Surveillance, Epidemiology, and End Results (SEER), the early breast cancer patients (T1-2N0-2M0) were extracted from 1998-2007. This study included 1,111 and 2,151 patients with early MBC and FBC, respectively, whose clinicopathological characteristics were well balanced. At a mean follow-up time of 97 months, 10-year OS rate was 58.3% in the MBC group and 68.7% in the FBC (log-rank test, P < 0.001; hazard ratio (HR) = 1.45, 95% confidence interval (CI) = 1.29 to 1.64). Adjusted HR for OS between MBC and FBC were revealed from propensity score matched-multivariable Cox proportional hazards models (HR = 1.53, 95% CI = 1.35 to 1.73). Similar adjusted SMRs between MBC and FBC ((SMR = 1.98, 95% CI = 1.83,2.14) for FBC and (SMR = 2.07, 95% CI = 1.88-2.28) for MBC) were observed. The nomogram was constructed for FBC, and predicted probabilities were generally good (C-index = 0.71), whose area under curve is higher than TNM stage classification (0.74 vs 0.62). OS was significantly decreased among early MBC patients compared with FBC, but similar SMRs and its trends by age groups were observed between MBC and FBC except for young patients.

Characterization of Korean Male Breast Cancer Using an Online Nationwide Breast-Cancer Database: Matched-Pair Analysis of Patients With Female Breast Cancer

The aim of this study is to review the characteristics and the survival rate in male breast cancer (MBC) patients in Korea over a 31-year period. Additionally, we analyzed the overall survival (OS) rate of a group of MBC matched to females with breast cancer. We retrospectively analyzed the data from 400 Korean patients who were treated for MBC from 1978 to 2009. Patient demographics and clinical information were routinely documented throughout the study period. Survival and prognostic factors were evaluated. Each MBC patient was matched with 5 female breast cancer (FBC) patients based on 7 characteristics and we compared the OS rates between the 2 groups. For MBC cases, the median follow-up was 72 months and the 5-year OS rate was 85.9%. In univariate analyses, the prognostic factors influencing OS were age (more than 60 years, P <0.001), tumor size (>2 cm, P = 0.007), and having a negative progesterone receptor (PR) status (P = 0.042). Only the age (P = 0.028) and tumor size (P = 0.024) were significant prognostic factors for OS in multivariate analysis. After matching, we had 260 male patients matched to 1300 female patients for analysis. Compared with cases among females, the rate of mastectomy was higher among MBC cases and tumors, which were almost invasive ductal carcinomas (IDCs), were more likely to be located in the central part of the breast. For MBC cases, the percentage of adjuvant radiation therapy was low compared with female cases. The primary hormone therapy agent used was tamoxifen. The 5-year OS rates were similar in MBC compared with FBC (91.0% vs. 92.6%, P = 0.300). We found that only the age (more than 60 years) and tumor size were independent prognostic factors of survival in MBC. The prognosis for MBC is similar to that for FBC given similar stage and hormone-receptor status.

Genome methylation patterns in male breast cancer - Identification of an epitype with hypermethylation of polycomb target genes

Male breast cancer (MBC) is a rare disease that shares both similarities and differences with female breast cancer (FBC). The aim of this study was to assess genome-wide DNA methylation profiles in MBC and compare them with the previously identified transcriptional subgroups of MBC, luminal M1 and M2, as well as the intrinsic subtypes of FBC. Illumina's 450K Infinium arrays were applied to 47 MBC and 188 FBC tumors. Unsupervised clustering of the most variable CpGs among MBC tumors revealed two stable epitypes, designated ME1 and ME2. The methylation patterns differed significantly between the groups and were closely associated with the transcriptional subgroups luminal M1 and M2. Tumors in the ME1 group were more proliferative and aggressive than ME2 tumors, and showed a tendency toward inferior survival. ME1 tumors also displayed hypermethylation of PRC2 target genes and high expression of EZH2, one of the core components of PRC2. Upon combined analysis of MBC and FBC tumors, ME1 MBCs clustered among luminal B FBC tumors and ME2 MBCs clustered within the predominantly luminal A FBC cluster. The majority of the MBC tumors remained grouped together within the clusters rather than being interspersed among the FBC tumors. Differences in the genomic location of methylated CpGs, as well as in the regulation of central canonical pathways may explain the separation between MBC and FBC tumors in the respective clusters. These findings further suggest that MBC is not readily defined using conventional criteria applied to FBC.

DEGRO practical guidelines for radiotherapy of breast cancer IV: radiotherapy following mastectomy for invasive breast cancer

BACKGROUND AND PURPOSE

Since the last recommendations from the Breast Cancer Expert Panel of the German Society for Radiation Oncology (DEGRO) in 2008, evidence for the effectiveness of postmastectomy radiotherapy (PMRT) has grown. This growth is based on updates of the national S3 and international guidelines, as well as on new data and meta-analyses. New aspects were considered when updating the DEGRO recommendations.

METHODS

The authors performed a comprehensive survey of the literature. Data from recently published (meta-)analyses, randomized clinical trials and international cancer societies' guidelines yielding new aspects compared to 2008 were reviewed and discussed. New aspects were included in the current guidelines. Specific issues relating to particular PMRT constellations, such as the presence of risk factors (lymphovascular invasion, blood vessel invasion, positive lymph node ratio >20 %, resection margins <3 mm, G3 grading, young age/premenopausal status, extracapsular invasion, negative hormone receptor status, invasive lobular cancer, size >2 cm or a combination of ≥ 2 risk factors) and 1-3 positive lymph nodes are emphasized.

RESULTS

The evidence for improved overall survival and local control following PMRT for T4 tumors, positive resection margins, >3 positive lymph nodes and in T3 N0 patients with risk factors such as lymphovascular invasion, G3 grading, close margins, and young age has increased. Recently identified risk factors such as invasive lobular subtype and negative hormone receptor status were included. For patients with 1-3 positive lymph nodes, the recommendation for PMRT has reached the 1a level of evidence.

CONCLUSION

PMRT is mandatory in patients with T4 tumors and/or positive lymph nodes and/or positive resection margins. PMRT should be strongly considered in patients with T3 N0 tumors and risk factors, particularly when two or more risk factors are present.

Treatment outcomes for male breast cancer: a single-centre retrospective case-control study

BACKGROUND

Male breast cancer (bc) is a rare disease, and the availability of information on treatment outcomes is limited compared with that for female bc. The objective of the present study was to compare disease-free (dfs) and overall survival (os) for men compared with women having early-stage bc.

METHODS

This retrospective case-control study compared men and women treated for stage 0-iiib bc at a single institution between 1981 and 2009. Matching was based on age at diagnosis, year of diagnosis, and stage. Treatment, recurrence, and survival data were collected. Kaplan-Meier analysis was used to calculate os and dfs.

RESULTS

For the 144 eligible patients (72 men, 72 women), median age at diagnosis was 66.5 years. Treatments included mastectomy (72 men, 38 women), radiation (29 men, 44 women), chemotherapy (23 men, 20 women), and endocrine therapy (57 men, 57 women). Mean dfs was 127 months for women compared with 93 months for men (p = 0.62). Mean os was 117 months for women compared with 124 months for men (p = 0.35). In multivariate analysis, the only parameter that affected both dfs and os was stage at diagnosis.

CONCLUSIONS

This case-control study is one of the largest to report treatment outcomes in early-stage male bc patients treated in a non-trial setting. Male patients received systemic therapy that was comparable to that received by their female counterparts, and they had similar os and dfs. These results add to current evidence from population studies that male sex is not a poor prognostic factor in early-stage breast cancer.

Molecular profiling of male breast cancer - lost in translation?

Breast cancer is the most common cancer form in women and it has been extensively studied on the molecular level. Male breast cancer (MBC), on the other hand, is rare and has not been thoroughly investigated in terms of transcriptional profiles or genomic aberrations. Most of our understanding of MBC has therefore been extrapolated from knowledge of female breast cancer. Although differences in addition to similarities with female breast cancer have been reported, the same prognostic and predictive markers are used to determine optimal management strategies for both men and women diagnosed with breast cancer. This review is focused on prognosis for MBC patients, prognostic and predictive factors and molecular subgrouping; comparisons are made with female breast cancer. Information was collected from relevant literature on both male and female breast cancer from the MEDLINE database between 1992 and 2014. MBC is a heterogeneous disease, and on the molecular level many differences compared to female breast cancer have recently been revealed. Two distinct subgroups of MBC, luminal M1 and luminal M2, have been identified which differ from the well-established intrinsic subtypes of breast cancer in women. These novel subgroups of breast cancer therefore appear unique to MBC. Furthermore, several studies report inferior survival for men diagnosed with breast cancer compared to women. New promising prognostic biomarkers for MBC (e.g. NAT1) deserving further attention are reviewed. Further prospective studies aimed at validating the novel subgroups and recently proposed biomarkers for MBC are warranted to provide the basis for optimal patient management in this era of personalized medicine. This article is part of a Directed Issue entitled: Rare Cancers.

Psychological impact of male breast disorders: literature review and survey results

BACKGROUND

Referrals of men to breast assessment clinics are increasing. While most of the men will have benign disease, some of them will have breast cancer. Whichever pathology they have, men should be offered a service tailored to their needs, rather than being 'shoehorned' into a service designed to care for women. This paper explores the psychological impact on men of their condition and of attending a breast assessment clinic.

METHODS

The literature regarding male experience of breast problems is reviewed, and screening for psychological morbidity is discussed. Results of a survey regarding an all-male breast assessment clinic are reported, with a plan for future research.

RESULTS

Many of the 78 men surveyed described negative feelings relating to their condition although they did not want to be seen in an all-male breast assessment clinic if that meant a longer wait. Men reported feelings of anxiety, embarrassment, emasculation and even depression regarding their condition.

CONCLUSIONS

Men are distressed by gynaecomastia and need psychological support for any breast-related presentation. More formalised research into this area is needed, although the men's distress does not translate into the desire to attend an all-male assessment clinic if this means a longer wait before being seen.

The landscape of candidate driver genes differs between male and female breast cancer

The rapidly growing collection of diverse genome-scale data from multiple tumor types sheds light on various aspects of the underlying tumor biology. With the objective to identify genes of importance for breast tumorigenesis in men and to enable comparisons with genes important for breast cancer development in women, we applied the computational framework COpy Number and EXpression In Cancer (CONEXIC) to detect candidate driver genes among all altered passenger genes. Unique to this approach is that each driver gene is associated with several gene modules that are believed to be altered by the driver. Thirty candidate drivers were found in the male breast cancers and 67 in the female breast cancers. We identified many known drivers of breast cancer and other types of cancer, in the female dataset (e.g. GATA3, CCNE1, GRB7, CDK4). In contrast, only three known cancer genes were found among male breast cancers; MAP2K4, LHP, and ZNF217. Many of the candidate drivers identified are known to be involved in processes associated with tumorigenesis, including proliferation, invasion and differentiation. One of the modules identified in male breast cancer was regulated by THY1, a gene involved in invasion and related to epithelial-mesenchymal transition. Furthermore, men with THY1 positive breast cancers had significantly inferior survival. THY1 may thus be a promising novel prognostic marker for male breast cancer. Another module identified among male breast cancers, regulated by SPAG5, was closely associated with proliferation. Our data indicate that male and female breast cancers display highly different landscapes of candidate driver genes, as only a few genes were found in common between the two. Consequently, the pathobiology of male breast cancer may differ from that of female breast cancer and can be associated with differences in prognosis; men diagnosed with breast cancer may consequently require different management and treatment strategies than women.

High proliferation is associated with inferior outcome in male breast cancer patients

Assessment of proliferation is important in female breast cancer and individual treatment decisions are based upon its results, especially in the luminal subgroups. Gene expression analyses fail to group male breast cancer into the intrinsic subgroups previously established in female breast cancer. Even though proliferation has been shown to divide male breast cancer into molecular subgroups with different prognoses, the clinical importance of proliferation markers has not yet been elucidated. Previous studies in male breast cancer have demonstrated contradictory results regarding the prognostic impact of histological grade and Ki-67, parameters strongly associated with proliferation. The aim of the present project was to study proliferation in male breast cancer by assessing other proliferation-related markers viz. cyclins A, B, D1 and mitotic count. A total of 197 male breast cancer cases with accessible paraffin-embedded material and outcome data were investigated. Immunohistochemical stainings were performed on tissue microarrays. Kaplan-Meier estimates and the Cox proportional regression models were used for survival analyses with breast cancer death as the event. The subset of patients with high expression of cyclin A (hazard ratio (HR) 3.7; P=0.001) and B (HR 2.7; P=0.02) demonstrated a poorer survival. Furthermore, high mitotic count was associated with an increased risk of breast cancer death (HR 2.5; P=0.01). In contrast, cyclin D1 overexpression was predictive of better breast cancer survival (HR 0.3; P=0.001). In conclusion, high levels of cyclin A and B expression and an elevated mitotic count result in a two to threefold higher risk for breast cancer death, whereas cyclin D1 overexpression halves the risk. The clinical utility of these proliferation markers needs further elucidation.

Molecular subtyping of male breast cancer using alternative definitions and its prognostic impact

BACKGROUND

Male breast cancer (MBC) is an uncommon disease and there is limited information on the prognostic impact of routinely used clinicopathological parameters.

MATERIAL AND METHODS

In a retrospective setting, we reviewed 197 MBC patients with accessible paraffin-embedded tumor tissue and clinicopathological data. Immunohistochemical (IHC) stainings were performed on tissue microarrays and histological grading on conventional slides. Cox proportional regression models were applied for uni- and multivariate analyses using breast cancer death as the event.

RESULTS

Estrogen receptor (ER) and progesterone receptor positivity were demonstrated in 93% and 77% of patients, respectively. Nottingham histologic grade (NHG) III was seen in 41% and HER2 positivity in 11%. Classification into molecular subtypes using IHC markers according to three alternative definitions revealed luminal A and luminal B in 81% vs. 11%; 48% vs. 44% and 41% vs. 42% of cases. Two cases of basal-like were identified, but no cases of HER2-like. Factors associated with an increased risk of breast cancer death were node positivity (HR 4.5; 95% CI 1.8-11.1), tumor size > 20 mm (HR 3.3; 95% CI 1.4-7.9) and ER negativity (HR 10.9; 95% CI 3.2-37.9). No difference in breast cancer death between the luminal subgroups was demonstrated, regardless of definition.

CONCLUSION

MBC tumors were more often of high grade, whereas HER2 overexpression was as frequent as in FBC. Lymph nodes, tumor size and ER status were independent predictors of breast cancer death. The prognostic impact of molecular subtyping in MBC seems to differ from that previously established in FBC.

PIK3CA mutations are frequently observed in BRCAX but not BRCA2-associated male breast cancer

INTRODUCTION

Although a substantial proportion of male breast cancers (MBCs) are hereditary, the molecular pathways that are activated are unknown. We therefore examined the frequency and clinicopathological associations of the PIK3CA/mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) pathways and their regulatory genes in familial MBC.

METHODS

High resolution melting analysis and confirmatory sequencing was used to determine the presence of somatic mutations in PIK3CA (exon 9 and 20), AKT1 (exon 4), KRAS (exon 2) and BRAF (exon 15) genes in 57 familial MBCs. Further analysis of the PIK3CA/mTOR pathway was performed using immunohistochemistry for the pAKT1, pS6 and p4EBP1 biomarkers.

RESULTS

PIK3CA somatic mutations were identified in 10.5% (6 of 57) of cases; there were no AKT1, KRAS or BRAF somatic mutations. PIK3CA mutations were significantly more frequent in cancers from BRCAX patients (17.2%, 5/29) than BRCA2 (0%, 0/25) carriers (P = 0.030). Two BRCAX patients had an E547K mutation which has only been reported in one female breast cancer previously. PIK3CA mutation was significantly correlated with positive pS6 (83.3% vs. 32.0%, P = 0.024) and negative p4EBP1 (100% vs. 38.0%, P = 0.006) expression, but not pAKT expression. Expression of nuclear p4EBP1 correlated with BRCA2 mutation carrier status (68.0% vs. 38.7%, P = 0.035).

CONCLUSIONS

Somatic PIK3CA mutation is present in familial male breast cancer but absent in BRCA2 carriers. The presence of two of the extremely rare E547K PIK3CA mutations in our cohort may have specific relevance in MBCs. Further study of PIK3CA in MBCs, and in particular BRCAX patients, may contribute to further establishing the relevance of specific PIK3CA mutations in MBC aetiology and in the identification of particular patient groups most likely to benefit from therapeutic targeting with the novel PIK3CA inhibitors that are currently in development.

Genotypic and phenotypic analysis of familial male breast cancer shows under representation of the HER2 and basal subtypes in BRCA-associated carcinomas

Background

Male breast cancer (MBC) is an uncommon and relatively uncharacterised disease accounting for <1% of all breast cancers. A significant proportion occurs in families with a history of breast cancer and in particular those carrying BRCA2 mutations. Here we describe clinicopathological features and genomic BRCA1 and BRCA2 mutation status in a large cohort of familial MBCs.

Methods

Cases (n=60) included 3 BRCA1 and 25 BRCA2 mutation carries, and 32 non-BRCA1/2 (BRCAX) carriers with strong family histories of breast cancer. The cohort was examined with respect to mutation status, clinicopathological parameters including TNM staging, grade, histological subtype and intrinsic phenotype.

Results

Compared to the general population, MBC incidence was higher in all subgroups. In contrast to female breast cancer (FBC) there was greater representation of BRCA2 tumours (41.7% vs 8.3%, p=0.0008) and underrepresentation of BRCA1 tumours (5.0% vs 14.4%, p=0.0001). There was no correlation between mutation status and age of onset, disease specific survival (DSS) or other clincopathological factors. Comparison with sporadic MBC studies showed similar clinicopathological features. Prognostic variables affecting DSS included primary tumour size (p=0.003, HR:4.26 95%CI 1.63-11.11), age (p=0.002, HR:4.09 95%CI 1.65-10.12), lymphovascular (p=0.019, HR:3.25 95%CI 1.21-8.74) and perineural invasion (p=0.027, HR:2.82 95%CI 1.13-7.06). Unlike familial FBC, the histological subtypes seen in familial MBC were more similar to those seen in sporadic MBC with 46 (76.7%) pure invasive ductal carcinoma of no special type (IDC-NST), 2 (3.3%) invasive lobular carcinomas and 4 (6.7%) invasive papillary carcinoma. A further 8 (13.3%) IDC-NST had foci of micropapillary differentiation, with a strong trend for co-occurrence in BRCA2 carriers (p=0.058). Most tumours were of the luminal phenotype (89.7%), with infrequent HER2 (8.6%) and basal (1.7%) phenotype tumours seen.

Conclusion

MBC in BRCA1/2 carriers and BRCAX families is different to females. Unlike FBC, a clear BRCA1 phenotype is not seen but a possible BRCA2 phenotype of micropapillary histological subtype is suggested. Comparison with sporadic MBCs shows this to be a high-risk population making further recruitment and investigation of this cohort of value in further understanding these uncommon tumours.

Are there biologic differences between male and female breast cancer explaining inferior outcome of men despite equal stage and treatment?!

BACKGROUND

Reasons for inferior outcome of male compared to female breast cancer are still under debate. Therefore, we retrospectively analyzed male breast cancer cases to figure out possible treatment- and gender-related differences.

PATIENTS AND METHODS

A total of 40 men (median age 62 years) were curatively treated with mastectomy and postoperative radiotherapy from 1982-2007. They presented predominantly in stages II and IIIb. Postoperative radiotherapy was applied with doses of 1.8-2.5 Gy to a median of 50 Gy including regional lymphatics in 22 patients. Adjuvant systemic treatment consisted of chemotherapy (22.5%) and antihormonal treatment (55%). For reasons of comparison, we estimated outcome of a virtual female matched cohort for no/equal to men/optimal adjuvant treatment with the Adjuvant!Online(®) 8.0 algorithm.

RESULTS

After a median follow-up of 47 months, the estimated 5-year local control rate was 97%, disease-free and distant metastasis-free survival rates reached 79% and 82%, respectively. With update of survival data by tumor registry, mean overall survival reached 120 months with 5- and 10-year overall survival rates of 66% and 43%, respectively. Predominant prognostic factor was T-stage for overall survival (T1/2 vs. T4: > 80% vs. 30%). The generated virtual matched cohorts of women with equal characteristics reached superior 10-year-overall survival for no/equal to men/optimal adjuvant treatment with 55/59/68%.

CONCLUSION

Compared to historical and virtual matched cohorts of women, male breast cancer patients had inferior outcome despite of equal stage and treatment which indicates that biological differences (of tumor or population) may contribute to worse prognosis.

Gene expression profiling of primary male breast cancers reveals two unique subgroups and identifies N-acetyltransferase-1 (NAT1) as a novel prognostic biomarker

INTRODUCTION

Male breast cancer (MBC) is a rare and inadequately characterized disease. The aim of the present study was to characterize MBC tumors transcriptionally, to classify them into comprehensive subgroups, and to compare them with female breast cancer (FBC).

METHODS

A total of 66 clinicopathologically well-annotated fresh frozen MBC tumors were analyzed using Illumina Human HT-12 bead arrays, and a tissue microarray with 220 MBC tumors was constructed for validation using immunohistochemistry. Two external gene expression datasets were used for comparison purposes: 37 MBCs and 359 FBCs.

RESULTS

Using an unsupervised approach, we classified the MBC tumors into two subgroups, luminal M1 and luminal M2, respectively, with differences in tumor biological features and outcome, and which differed from the intrinsic subgroups described in FBC. The two subgroups were recapitulated in the external MBC dataset. Luminal M2 tumors were characterized by high expression of immune response genes and genes associated with estrogen receptor (ER) signaling. Luminal M1 tumors, on the other hand, despite being ER positive by immunohistochemistry showed a lower correlation to genes associated with ER signaling and displayed a more aggressive phenotype and worse prognosis. Validation of two of the most differentially expressed genes, class 1 human leukocyte antigen (HLA) and the metabolizing gene N-acetyltransferase-1 (NAT1), respectively, revealed significantly better survival associated with high expression of both markers (HLA, hazard ratio (HR) 3.6, P = 0.002; NAT1, HR 2.5, P = 0.033). Importantly, NAT1 remained significant in a multivariate analysis (HR 2.8, P = 0.040) and may thus be a novel prognostic marker in MBC.

CONCLUSIONS

We have detected two unique and stable subgroups of MBC with differences in tumor biological features and outcome. They differ from the widely acknowledged intrinsic subgroups of FBC. As such, they may constitute two novel subgroups of breast cancer, occurring exclusively in men, and which may consequently require novel treatment approaches. Finally, we identified NAT1 as a possible prognostic biomarker for MBC, as suggested by NAT1 positivity corresponding to better outcome.