Tumor subtypes and survival in male breast cancer

Predicting Late Recurrence in Male Estrogen Receptor-Positive Breast Cancer With Clinical Treatment Score Post-5 years: A SEER database analysis of 65,711 cases

PURPOSE

Male breast cancer is an understudied disease with unique clinicopathological features. This study aims to evaluate the predictive value of the Clinical Treatment Score post-5 years (CTS5) in estimating late recurrence risk in estrogen receptor-positive (ER+) male breast cancer patients.

METHODS

This retrospective study includes 65,711 ER+ early male (n = 611) and female (n = 65,100) breast cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database diagnosed between 2010 and 2018. The main outcome measured was breast cancer-specific survival (BCSS) after 5 years of diagnosis. The CTS5 was calculated using their clinicopathological features.

RESULTS

Male breast cancer was more likely to be diagnosed later in life, with more aggressive biological features, and higher tumor burden comparing to female counterparts. More male patients were CTS5 intermediate- or high-risk than female patients (high 7.9% vs. 6.3%, intermediate 41.1% vs. 24.6%, P < .001). The 5-year BCSS rate was 89.1% (95% CI, 86.4%-91.8%) in the male patients and 93.5% (95% CI, 93.3%-93.7%) in the female patients. At median follow up of 77 months, in the male breast cancer patients without progression after 5 years of diagnosis, BCSS rate was significantly lower in the CTS5 high-risk group (HR 6.44; 95% CI, 1.54-26.97; P = .011) and intermediate-risk group (HR 5.61; 95% CI, 2.00-26.97; P = .001), when compared with the low-risk group.

CONCLUSIONS

Male breast cancer patients have distinct clinicopathological features and worse survival outcomes. The CTS5 could predict breast cancer recurrence beyond 5 years of diagnosis in ER+ male breast cancer patients, which may aid in personalized treatment decisions.

Redefining therapeutic landscapes: clinicopathological insights into low and ultra-low HER2 expression in male breast cancer

OBJECTIVE

With the emergence of new antibody coupled drugs, the treatment decisions of patients with low and ultra-low HER2 expression have been reshaped. However, the epidemiological characteristics of relatively rare male breast cancer are still unclear. This study discusses the clinicopathological and immunophenotypic characteristics of male invasive breast cancer with low and ultra-low HER2 expression.

METHODS

The clinicopathological and immunophenotypic features of 106 cases of male invasive breast cancer were retrospectively analyzed. HER2 was evaluated according to ASCO/CAP guidelines. The cutoff value of HER2 positive cell staining was > 10%. HER2 negative cases were divided into HER2 low expression (IHC = 1+/2 + and ISH without amplification) and HER2-0 (IHC-0, HER2 null and < 10% weak staining of cell membrane). The clinicopathological characteristics and prognosis of the cases were collected.

RESULTS

106 male patients with invasive breast cancer from 2015 to 2024 were included in this study, and more than 85% of male breast cancer histological types were invasive ductal carcinoma. Immunophenotype: There were 23 cases of HER2-zero (including 13 cases of HER2 ultra-low), 72 cases of HER2 low, 11 cases of HER2 positive, and the HER2 positive rate was 10.38%, and the incidence of low expression was 67.93%; The incidence of HER2 low in male breast cancer was significantly higher than that in female breast cancer, and the difference was statistically significant (P < 0.05). In terms of prognosis, there was no statistical difference between HER2 low male breast cancer and female breast cancer (P > 0.05). There was no statistical difference in survival prognosis between different HER2 status in the male breast cancer cohort.

CONCLUSION

Male invasive breast cancer is rare, and it is more common in the elderly over 60 years old. The positive rate of ER and PR is high, and the incidence of HER2 low is high. The high HER2 low expression rate of male breast cancer can provide a new anti-HER2 treatment decision.

Predicting Overall Survival in Patients with Male Breast Cancer: Nomogram Development and External Validation Study

Background

Male breast cancer (MBC) is an uncommon disease. Few studies have discussed the prognosis of MBC due to its rarity.

Objective

This study aimed to develop a nomogram to predict the overall survival of patients with MBC and externally validate it using cases from China.

Methods

Based on the Surveillance, Epidemiology, and End Results (SEER) database, male patients who were diagnosed with breast cancer between January 2010, and December 2015, were enrolled. These patients were randomly assigned to either a training set (n=1610) or a validation set (n=713) in a 7:3 ratio. Additionally, 22 MBC cases diagnosed at the First Affiliated Hospital of Guangxi Medical University between January 2013 and June 2021 were used for external validation, with the follow-up endpoint being June 10, 2023. Cox regression analysis was performed to identify significant risk variables and construct a nomogram to predict the overall survival of patients with MBC. Information collected from the test set was applied to validate the model. The concordance index (C-index), receiver operating characteristic (ROC) curve, decision curve analysis (DCA), and a Kaplan-Meier survival curve were used to evaluate the accuracy and reliability of the model.

Results

A total of 2301 patients with MBC in the SEER database and 22 patients with MBC from the study hospital were included. The predictive model included 7 variables: age (hazard ratio [HR] 1.89, 95% CI 1.50-2.38), surgery (HR 0.38, 95% CI 0.29-0.51), marital status (HR 0.75, 95% CI 0.63-0.89), tumor stage (HR 1.17, 95% CI 1.05-1.29), clinical stage (HR 1.41, 95% CI 1.15-1.74), chemotherapy (HR 0.62, 95% CI 0.50-0.75), and HER2 status (HR 2.68, 95% CI 1.20-5.98). The C-index was 0.72, 0.747, and 0.981 in the training set, internal validation set, and external validation set, respectively. The nomogram showed accurate calibration, and the ROC curve confirmed the advantage of the model in clinical validity. The DCA analysis indicated that the model had good clinical applicability. Furthermore, the nomogram classification allowed for more accurate differentiation of risk subgroups, and patients with low-risk MBC demonstrated substantially improved survival outcomes compared with medium- and high-risk patients (P<.001).

Conclusions

A survival prognosis prediction nomogram with 7 variables for patients with MBC was constructed in this study. The model can predict the survival outcome of these patients and provide a scientific basis for clinical diagnosis and treatment.

Real-word study of racial/ethnic disparities and socioeconomic determinants of overall survival in male breast cancer

This study assessed racial/ethnic disparities and socioeconomic determinants of overall survival in male breast cancer. Using the 2010-2021 US National Cancer Database, we identified 20,470 patients: 78.2% White, 13.8% Black, 4.0% Hispanic, and 2.5% Asian or Pacific Islander. After adjusting for clinicopathologic characteristics, Black patients had higher mortality than White patients (adjusted hazard ratio [AHR] 1.22, 95% CI: 1.12-1.32); however, when further adjusting for socioeconomic factors, this difference was no longer significant (AHR 1.09, 95% CI: 0.99-1.21). Hispanic patients had better survival. In the TNBC cohort, Asian or Pacific Islander patients had higher mortality than White patients (AHR 2.35, 95% CI: 1.21-4.55), warranting further investigation. In this US male breast cancer cohort, Black patients and White patients had similar mortality risk after further adjusting for socioeconomic indicators. Higher median household income and private insurance were linked to better survival. Strategies addressing socioeconomic inequities may help improve male breast cancer outcomes.

Characteristics and Survival Outcomes of Male Breast Cancer in Brazil: A Large Population-Based Study

AIMS

This study evaluated the clinicopathological characteristics, treatment trends, and overall survival (OS) in male breast cancer (BC) in Sao Paulo State of Brazil.

MATERIALS AND METHODS

Men diagnosed with invasive breast cancer between January 2000 and June 2020 were identified from Fundação Oncocentro de Sao Paulo database encompasses data pertinent to 46 million residents of the Sao Paulo State of Brazil. Patients were described according to age, education level, clinical stage, treatment modalities, and medical practice. Categorical variables were described as percentages and frequencies. Demographic, treatment factors, and OS were associated using a Cox proportional hazard regression model while accounting for different lengths of participant follow-up. The Kaplan-Meier curves were used to display survival curves.

RESULTS

A total of 907 male BC patients were included. The age distribution at diagnosis was <51 years, 51-70 years, and >70 years in 21.5%, 51.5% and 27.0% of patients, respectively. The proportions of stages I, II, III, and IV were 19.5%, 36.6%, 31.5%, and 12.3%. For each stage I, II, III, and IV, 5- and 10-years OS were 87.9% and 77.8%, 79.9% and 58.9%, 51.6% and 24.5%, 20.0% and 5.6%, respectively. Patients who received postoperative radiotherapy experienced a significant improvement in OS (HR 0.67; 95% CI 0.53-0.84; p < 0.001). In the multivariable analysis adjusted for practice (public or private), education (low or medium/high), age, stage at diagnosis, and treatment modalities, the significant independent predictor for OS was stage at diagnosis.

CONCLUSION

Male BC tends to be diagnosed at a more advanced stage and older age at the time of diagnosis. Age and educational level did not influence survival outcomes. Stage at diagnosis and the use of postoperative radiotherapy were factors associated with improved OS.

Influence of tumour grade on disease survival in male breast cancer patients: a systematic review

PURPOSE

Histological grading of tumours is a well-established biomarker used to guide treatment in female breast cancer. However, its significance in male breast cancer remains unclear. This systematic review investigates the prognostic significance of tumour grade in relation to breast cancer-specific survival (BCSS) in male breast cancer patients undergoing surgery.

METHODS

MEDLINE, PUBMED Central and EMBASE databases were searched to identify randomised trials and observational studies related to male breast neoplasms, tumour grading, recurrence, and survival.

RESULTS

A total of fifteen observational type studies were included in the review. A significant association between tumour grade and BCSS was reported in a majority of studies. This association was most evident with regard to high-grade (grade III) compared to low grade (grade I) tumours, with a significant relationship in 4 out of 4 studies. For intermediate-grade II tumours an association was demonstrated in a minority of studies.

CONCLUSIONS

This study confirms an association between high-grade male breast cancers and poorer disease-specific survival, however, the significance of intermediate-grade tumours remains unclear. Further research is required to investigate the biology of male breast cancer in relation to histological grade and optimally define intermediate-grade disease.

Protein biomarkers for subtyping breast cancer and implications for future research: a 2024 update

INTRODUCTION

Breast cancer subtyping is used clinically for diagnosis, prognosis, and treatment decisions. Subtypes are categorized by cell of origin, histomorphology, gene expression signatures, hormone receptor status, and/or protein levels. Categorizing breast cancer based on gene expression signatures aids in assessing a patient's recurrence risk. Protein biomarkers, on the other hand, provide functional data for selecting therapies for primary and recurrent tumors. We provide an update on protein biomarkers in breast cancer subtypes and their application in prognosis and therapy selection.

AREAS COVERED

Protein pathways in breast cancer subtypes are reviewed in the context of current protein-targeted treatment options. PubMed, Science Direct, Scopus, and Cochrane Library were searched for relevant studies between 2017 and 17 August 2024.

EXPERT OPINION

Post-translationally modified proteins and their unmodified counterparts have become clinically useful biomarkers for defining breast cancer subtypes from a therapy perspective. Tissue heterogeneity influences treatment outcomes and disease recurrence. Spatial profiling has revealed complex cellular subpopulations within the breast tumor microenvironment. Deciphering the functional relationships between and within tumor clonal cell populations will further aid in defining breast cancer subtypes and create new treatment paradigms for recurrent, drug resistant, and metastatic disease.

The features of male breast cancer in China: A real-world study

BACKGROUND

Male breast cancer (MBC) is a rare disease. Although several large-scale studies have investigated MBC patients in other countries, the features of MBC patients in China have not been fully explored. This study aims to explore the features of Chinese MBC patients comprehensively.

METHODS

We retrospectively collected data of MBC patients from 36 centers in China. Overall survival (OS) was evaluated by the Kaplan-Meier method, log-rank test, and Cox regression analyses. Multivariate Cox analyses were used to identify independent prognostic factors of the patients.

RESULTS

In total, 1119 patients were included. The mean age at diagnosis was 60.9 years, and a significant extension over time was observed (P < 0.001). The majority of the patients (89.1 %) received mastectomy. Sentinel lymph node biopsy was performed in 7.8 % of the patients diagnosed in 2009 or earlier, and this percentage increased significantly to 38.8 % in 2020 or later (P < 0.001). The five-year OS rate for the population was 85.5 % [95 % confidence interval (CI), 82.8 %-88.4 %]. Multivariate Cox analysis identified taxane-based [T-based, hazard ratio (HR) = 0.32, 95 % CI, 0.13 to 0.78, P = 0.012] and anthracycline plus taxane-based (A + T-based, HR = 0.47, 95 % CI, 0.23 to 0.96, P = 0.037) regimens as independent protective factors for OS. However, the anthracycline-based regimen showed no significance in outcome (P = 0.175).

CONCLUSION

As the most extensive MBC study in China, we described the characteristics, treatment and prognosis of Chinese MBC population comprehensively. T-based and A + T-based regimens were protective factors for OS in these patients. More research is required for this population.

Genomic profiling and comparative analysis of male versus female metastatic breast cancer across subtypes

BACKGROUND

Male breast cancer (MaBC) has limited data on genomic alterations. We aimed to comprehensively describe and compare MaBC's genomics with female breast cancer's (FBC) across subtypes.

METHODS

Using genomic data from Foundation Medicine, we categorized 253 MaBC into estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative (n = 210), ER-positive/HER2-positive (n = 22) and triple-negative (n = 20). One ER-negative/HER2-positive case was excluded due to n-of-1. The genomics of the final MaBC cohort (n = 252) were compared to a FBC cohort (n = 2708) stratified by molecular subtype, with adjusted p-values. In the overall MaBC and FBC cohorts, we compared mutational prevalence in cancer susceptibility genes (CSG) (ATM/BRCA1/BRCA2/CHEK2/PALB2).

RESULTS

Comparing ER-positive/HER2-negative cases, MaBc had increased alterations in GATA3 (26.2% vs. 15.9%, p = 0.005), BRCA2 (13.8% vs. 5.3%, p < 0.001), MDM2 (13.3% vs. 6.14%, p = 0.004) and CDK4 (7.1% vs. 1.8%, p < 0.001); and decreased frequency of TP53 (11.0% vs. 42.6%, p < 0.001) and ESR1 mutations (5.7% vs. 14.6%, p < 0.001). Comparing ER-positive/HER2-positive cases, MaBC had increased short variants in ERBB2 (22.7% vs. 0.6%, p = 0.002), GATA3 (36.3% vs. 6.2%, p = 0.004), and MDM2 (36.3% vs. 4.9%, p = 0.002); decreased frequency of TP53 alterations was seen in MaBC versus FBC (9.1% vs. 61.7%, p < 0.001). Within triple-negative cases, MaBC had decreased alterations in TP53 compared to FBC (25.0% vs. 84.4%, p < 0.001). MaBC had higher frequency of CSG variants than FBC (22.6% vs. 14.6%, p < 0.05), with increased BRCA mutations in MaBC (14.6% vs. 9.1%, p < 0.05).

CONCLUSIONS

Although MaBC and FBC share some common alterations, our study revealed several important differences relevant to tumor biology and implications for targeted therapies.

Gender minorities in breast cancer - Clinical trials enrollment disparities: Focus on male, transgender and gender diverse patients

BACKGROUND

The last years have seen unprecedented improvement in breast cancer (BC) survival rates. However, this entirely apply to female BC patients, since gender minorities (male, transgender/gender-diverse) are neglected in BC phase III registration clinical trials.

METHODS

We conducted a scoping review of phase III clinical trials of agents with a current positioning within the therapeutic algorithms of BC.

RESULTS

We selected 51 phase III trials. Men enrollment was allowed in 35.3% of trials. In none of the trial inclusion/exclusion criteria referred to transgender/gender-diverse people. A numerical higher rate of enrolled men was observed in the contemporary as compared to historical group. We found a statistically significant association between the drug class and the possibility of including men: 100%, 80%, 50%, 33.3%, 25%, 10% and 9.1% of trials testing ICI/PARP-i, ADCs, PI3K/AKT/mTOR-i, anti-HER2 therapy, CDK4/6-i, ET alone, and CT alone. Overall, 77409 patients were enrolled, including 112 men (0.2%). None of the trial reported transgender/gender-diverse people proportion. Studies investigating PARP-i were significantly associated with the highest rate of enrolled men (1.42%), while the lowest rates were observed for trials of CT (0.13%), ET alone (0.10%), and CDK 4/6-I (0.08%), p < 0.001.

CONCLUSIONS

We confirmed that gender minorities are severely underrepresented among BC registration trials. We observed a lower rate of men in trials envisaging endocrine manipulation or in less contemporary trials. This work sought to urge the scientific community to increase the awareness level towards the issue of gender minorities and to endorse more inclusive criteria in clinical trials.

Is There a Survival Difference Between Male and Female Breast Cancer Subtypes According to the Prognostic Staging System? A Population-Based Cohort Study

BACKGROUND

In retrospective studies investigating the difference in survival by gender, there are conflicting results. It was aimed to compare overall survival (OS) and breast cancer-specific survival (BCSS) in male and female breast cancer subtypes according to the prognostic staging system.

METHODS

Overall survival rates and BCSS rates of patients diagnosed with breast cancer between 2010 and 2019 compared by gender for all cohorts, stages, and molecular subtypes using the SEER Database. The stage has been rearranged according to the eighth edition of the AJCC.

RESULTS

364 039 patients were included in the study. .7% (n = 2503) of all breast cancers were male breast cancer. Overall survival (male: 5-year OS 73.9%, female = 5-year OS 86%) and BCSS rates (male: 5-year BCSS 78.9%, female = 5-year BCSS 94.7%) were significantly higher in females than in males for all cohorts. OS (male: 5-year OS 66.2% vs female: 5-year OS 88.3%), and BCSS (male: 5-year BCSS 88.4% vs female: 5-year 93.6%) rates were higher in hormone receptor (HR)-positive/Her2-negative female patients. Overall survival rate is higher in females in stage I (male: 5-year OS 81.5%, female: 5-year OS 92.8%), and BCSS rate is higher in stage I (male: 5-year BCSS 94.8%, female: 5-year BCSS 97.5%). Males have 2 times (HR = 2.023) higher overall mortality risk than females, but the risk of dying from breast cancer is only 1.6 times (HR = 1.596) higher.

CONCLUSIONS

Breast cancer-specific mortality is significantly higher in male breast cancers, especially in the early stage, and HR-positive subtype than females.

Mortality Risks Over 20 Years in Men With Stage I to III Hormone Receptor-Positive Breast Cancer

Importance

In women with hormone receptor-positive (HR+) breast cancer, the risk of distant recurrence and death persists for at least 20 years from diagnosis. The risk of late mortality in men with HR+ breast cancer has not been reported.

Objective

To report 20-year risks of breast cancer-specific mortality (BCSM) and non-BCSM in men with stage I to III HR+ breast cancer and identify factors associated with late BCSM.

Design, Setting, and Participants

An observational cohort study was conducted of men diagnosed with HR+ breast cancer from 1990 to 2008, using population-based data from the Surveillance, Epidemiology, and End Results program. Men diagnosed with stage I to III HR+ breast cancer were included in the analysis. Cumulative incidence function was used to estimate the outcomes of baseline clinicopathologic variables regarding cumulative risk of BCSM and non-BCSM since diagnosis. Smoothed hazard estimates over time were plotted for BCSM. Fine and Gray multivariable regression evaluated the association of preselected variables with BCSM, conditional on having survived 5 years.

Main Outcome Measure

BCSM.

Results

A total of 2836 men with stage I to III HR+ breast cancer were included, with a median follow-up of 15.41 (IQR, 12.08-18.67) years. Median age at diagnosis was 67 (IQR, 57-76) years. The cumulative 20-year risk of BCSM was 12.4% for stage I, 26.2% for stage II, and 46.0% for stage III. Smoothed annual hazard estimates for BCSM revealed an increase in late hazard rates with each incremental node category, reaching a bimodal distribution in N3 and stage III, with each having peaks in hazard rates at 4 and 11 years. Among patients who survived 5 years from diagnosis, the adjusted BCSM risk was higher for those younger than 50 years vs older than 64 years, those with grade II or III/IV vs grade I tumors, and stage II or III vs stage I disease.

Conclusions and Relevance

The findings of this study suggest that, in men with stage I to III HR+ breast cancer, the risk of BCSM persists for at least 20 years and depends on traditional clinicopathologic factors, such as age, tumor stage, and tumor grade. Among men with higher stages of disease, the kinetics of the BCSM risk appear different from the risk that has been reported in women.

Survival Analysis of Male Patients with Brain Metastases at Initial Breast Cancer Diagnosis over the Last Decade

Breast cancer in men represents approximately 1% of all breast cancer diagnoses. Among all patients with breast cancer, approximately 30% will develop brain metastases. Over the past decade, there have been multiple advances in the treatment of metastatic breast cancer; however, long-term outcomes of this presentation in male patients are lacking. We evaluated male patients with de novo stage IV breast cancer using the Surveillance, Epidemiology and End Results (SEER) database from 2010 to 2019. Overall survival (OS) was estimated using the Kaplan-Meier method and differences between groups were compared using log rank tests. In total, 22 male patients with brain metastases at initial breast cancer diagnosis were included. Patients with HR-positive/HER2-negative tumors had the longest OS (median 13 months). Factors associated with shorter overall survival were advanced age, unmarried marital status, lower household income, and grade III disease, among others. Brain metastases remains an unmet medical need for patients with breast cancer; the development of new drugs may provide an improvement in overall survival for male patients in the future.

Outcomes of male patients with HR+/HER2- advanced breast cancer receiving palbociclib in the real-world POLARIS study

PURPOSE

Data on treatments for male breast cancer patients are limited owing to rarity and underrepresentation in clinical trials. The real-world POLARIS study gathers data on palbociclib use for the treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) in female and male patients. This sub-analysis describes real-world palbociclib treatment patterns, clinical outcomes, and quality of life (QoL) in male patients.

METHODS

POLARIS is a prospective, noninterventional, multicenter, real-world study of patients with HR+/HER2- ABC receiving palbociclib. Assessments included medical record reviews, patient QoL questionnaires (European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire-Core 30), site characteristics questionnaires, and physician treatment selection surveys. Variables included demographics, disease history, global health status/QoL, clinical assessments and adverse events. Analyses were descriptive in nature. For clinical outcomes, real-world tumor responses and progression were determined by physician assessment in routine clinical practice. Real-world progression-free survival (rwPFS) was described using the Kaplan-Meier method.

RESULTS

At data cutoff, 15 male patients were enrolled (median age, 66 years). Nine patients received palbociclib as a first-line treatment and 6 as a second-line or later treatment. Patients received a median of 20 cycles of palbociclib. Neutropenia was experienced by 2 patients and grade ≥ 3 adverse events were reported in 11 patients. Global health status/QoL scores remained generally consistent during the study. One patient (6.7%) achieved a complete tumor response, 4 (26.7%) a partial response, and 8 (53.3%) stable disease. Median rwPFS was 19.8 months (95% CI, 7.4-38.0). Median follow-up duration was 24.7 months (95% CI, 20.0-35.7).

CONCLUSION

This real-world analysis showed that palbociclib was well tolerated and provides preliminary data on treatment patterns and outcomes with palbociclib in male patients with HR+/HER2- ABC, helping inform the use of palbociclib in this patient subgroup.

TRIAL IDENTIFIER

NCT03280303.

Nomograms predict survival in elderly women with triple-negative breast cancer: A SEER population-based study

BACKGROUND

The effective treatment of breast cancer in elderly patients remains a major challenge.

OBJECTIVE

To construct a nomogram affecting the overall survival of triple-negative breast cancer (TNBC) and establish a survival risk prediction model.

METHODS

A total of 5317 TPBC patients with negative expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) who were diagnosed and received systematic treatment from 2010 to 2015 were collected from the American Cancer Surveillance, Epidemiology and End Results (SEER) database. They were randomly divided into training set (n= 3721) and validation set (n= 1596). Univariate and multivariate Cox regression analysis were used to identify prognostic features, and a nomogram was established to predict the probability of 1-year, 3-year and 5-year OS and BCSS. We used consistency index (C-index), calibration curve, area under the curve (AUC) and decision curve analysis (DCA) to evaluate the predictive performance and clinical utility of the nomogram.

RESULTS

The C-indices of the nomograms for OS and BCSS in the training cohort were 0.797 and 0.825, respectively, whereas those in the validation cohort were 0.795 and 0.818, respectively. The receiver operating characteristic (ROC) curves had higher sensitivity at all specificity values as compared with the Tumor Node Metastasis (TNM) system. The calibration plot revealed a satisfactory relationship between survival rates and predicted outcomes in both the training and validation cohorts. DCA demonstrated that the nomogram had clinical utility when compared with the TNM staging system.

CONCLUSION

This study provides information on population-based clinical characteristics and prognostic factors for patients with triple-negative breast cancer, and constructs a reliable and accurate prognostic nomogram.

Prediction models for hormone receptor status in female breast cancer do not extend to males: further evidence of sex-based disparity in breast cancer

Breast cancer prognosis and management for both men and women are reliant upon estrogen receptor alpha (ERα) and progesterone receptor (PR) expression to inform therapy. Previous studies have shown that there are sex-specific binding characteristics of ERα and PR in breast cancer and, counterintuitively, ERα expression is more common in male than female breast cancer. We hypothesized that these differences could have morphological manifestations that are undetectable to human observers but could be elucidated computationally. To investigate this, we trained attention-based multiple instance learning prediction models for ERα and PR using H&E-stained images of female breast cancer from the Cancer Genome Atlas (TCGA) (n = 1085) and deployed them on external female (n = 192) and male breast cancer images (n = 245). Both targets were predicted in the internal (AUROC for ERα prediction: 0.86 ± 0.02, p < 0.001; AUROC for PR prediction = 0.76 ± 0.03, p < 0.001) and external female cohorts (AUROC for ERα prediction: 0.78 ± 0.03, p < 0.001; AUROC for PR prediction = 0.80 ± 0.04, p < 0.001) but not the male cohort (AUROC for ERα prediction: 0.66 ± 0.14, p = 0.43; AUROC for PR prediction = 0.63 ± 0.04, p = 0.05). This suggests that subtle morphological differences invisible upon visual inspection may exist between the sexes, supporting previous immunohistochemical, genomic, and transcriptomic analyses.

Proton Therapy in the Treatment of Men with Breast Cancer

Purpose

Male breast cancer treatment involves multimodality therapy, including radiation therapy; nevertheless, few men have received proton therapy (PT) for it. Further, heart disease is an established leading cause of death in men, and radiation therapy heart dose correlates with cardiac toxicity, highlighting the need for cardiac-sparing radiation techniques. Thus, we provide a descriptive analysis of PT in a male breast cancer cohort.

Patients and Methods

Men who received PT for localized breast cancer between 2012 and 2022 were identified from a prospective database. Toxicities were prospectively recorded by using the Common Terminology Criteria for Adverse Events (CTCAE), version 4.0.

Results

Five male patients were identified. All had estrogen receptor (ER)-positive, Her2neu-negative disease and received adjuvant endocrine therapy. One had genetic testing positive for BRCA2, one had a variant of unknown significance (VUS) in the APC gene, and one had a VUS in MSH2. Median age was 73 years (range, 41-80). Baseline comorbidities included obesity (n = 1), diabetes (n = 1), hypertension (n = 4), history of deep vein thrombosis (n = 1), personal history of myocardial infarction (n = 3; 1 with a pacemaker), and a history of lung cancer (n = 1). All received PT to the left chest wall and comprehensive regional lymphatics. One received passive-scattering PT, and 4 received pencil beam scanning. One patient received a boost to the mastectomy incision via electrons. Median heart dose was 1 GyRBE (range, 0-1.0), median 0.1-cm3 dose to the left anterior descending artery was 7.5 GyRBE (range, 0-14.2), and median follow-up was 2 years (range, 0.75-6.5); no patient experienced a new cardiac event, and all remain free from breast cancer recurrence and progression.

Conclusion

In a small case series for a rare diagnosis, PT to the chest wall and regional lymphatics, including internal mammary nodes, resulted in low cardiac exposure, high local regional disease control rates, and minimal toxicity. Proton therapy should be considered for treating men with breast cancer to achieve cardiac sparing.

Survival in male breast cancer over the past 3 decades

BACKGROUND

Breast cancer mortality in women has declined statistically significantly over the past several years. In men, it is unclear whether survival has changed over time. We evaluated changes in breast cancer-specific survival (BCSS) and overall survival (OS) in male breast cancer over the past 3 decades.

METHODS

We evaluated men diagnosed with breast cancer between 1988 and 2017, reported in the Surveillance, Epidemiology, and End Results registry. Patients were categorized into 3 groups by year of diagnosis: 1988-1997, 1998-2007, and 2008-2017. BCSS and OS were estimated by Kaplan-Meier, and differences between groups were compared by log-rank test. Multivariable Cox regression evaluated the independent association of year of diagnosis with BCSS and OS. All tests were 2-sided.

RESULTS

We included 8481 men. Overall, BCSS at 5 years was 83.69%, 83.78%, and 84.41% in groups 1988-1997, 1998-2007, and 2008-2017, respectively (P = .86). There was no statistically significant difference in BCSS between the 3 groups within each stage of disease. Among all patients, OS at 5 years was 64.61%, 67.31%, and 69.05% in groups 1988-1997, 1998-2007, and 2008-2017, respectively (P = .01). In adjusted Cox models, each additional year of diagnosis had no statistically significant association with BCSS (hazard ratio = 1.00, 95% confidence interval = 0.99 to 1.01, P = .75), but there was statistically significant improvement in OS (hazard ratio = 0.99, 95% CI = 0.98 to 0.99, P = .009).

CONCLUSIONS

Over the past 3 decades, there has been no statistically significant improvement in BCSS in male breast cancer. Changes in OS over time are consistent with increasing life expectancy. Efforts to improve BCSS in male breast cancer are warranted.

Defining genomic, transcriptomic, proteomic, epigenetic, and phenotypic biomarkers with prognostic capability in male breast cancer: a systematic review

Although similar phenotypically, there is evidence that male and female breast cancer differ in their molecular landscapes. In this systematic review, we consolidated all existing prognostic biomarker data in male breast cancer spanning genetics, transcriptomics, proteomics, and epigenetics, and phenotypic features of prognostic value from articles published over a 29-year period (March 16, 1992, to May 1, 2021). We identified knowledge gaps in the existing literature, discussed limitations of the included studies, and outlined potential approaches for translational biomarker discovery and validation in male breast cancer. We also recognised STC2, DDX3, and DACH1 as underexploited markers of male-specific prognostic value in breast cancer. Finally, beyond describing the cumulative knowledge on the extensively researched markers oestrogen receptor-α, progesterone receptor, HER2, androgen receptor, and BRCA2, we highlighted ATM, CCND1, FGFR2, GATA3, HIF1-α, MDM2, TP53, and c-Myc as well studied predictors of poor survival that also aligned with several hallmarks of cancer.

HR+/HER2- de novo metastatic breast cancer: a true peculiar entity?

De novo metastatic breast cancer (dnMBC) accounts for ~6-10% of all breast cancers and for ~30% of MBC with increasing incidence over time. Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR⁺/HER2^-) tumours are the most frequent subtype with a similar incidence to that observed amongst recurrent MBC (rMBC). Higher frequency of PI3KCA and ARID2 mutations and a lower frequency of ESR1 mutations and of genes involved in DNA damage, as compared with rMBC, have been reported in HR⁺/HER2^- dnMBC; however, these are not correlating with prognosis, whilst tumour mutational burden is inversely correlated with outcome. Bone represents the most frequent metastatic site, being the single site in up to 60% of patients with dnMBC. HR⁺/HER2^- dnMBC has been generally reported to have better outcomes than rMBC, with a median overall survival ranging from 26 months to nearly 5 years in patients with favourable features such as age <40 years and bone-only disease, but not when compared with patients with late recurring disease (≥2-5 years). Analyses of the de novo cohorts within randomized clinical trials and large real-world series report a better outcome after treatment with CDK4/6 inhibitors and endocrine agents as compared to rMBC. Despite the limitations of retrospective studies and controversial results of the randomized trials, locoregional treatment of the primary tumour after response to systemic therapy appears to confer a survival benefit, particularly in patients with favourable prognostic factors. Altogether genomic, biological and clinical findings highlight HR⁺/HER2^- dnMBC as a peculiar entity as compared with rMBC and deserve a dedicated treatment algorithm. This article is part of the Tackling clinical complexity in breast cancer Special Issue: https://www.drugsincontext.com/special_issues/tackling-clinical-complexity-in-breast-cancer/.

Male breast cancer: a 20-year multicenter experience

Aim: Male breast cancer (MBC) is a rare disease and accounts for approximately 1% of breast cancer. Treatment is largely extrapolated from female breast cancer due to lack of data in MBC. However, there are distinct features of MBC that warrant different treatment approach. We aim to better characterize the risk factors, clinicopathologic features, treatment and outcome of MBC patients from six hospitals across Steward Healthcare Network. Materials & methods: A total of 107 men with breast cancer were identified from the respective cancer registry at Steward and 64 patients were included with complete medical records. Their clinical, histopathological and treatment records were retrospectively reviewed. Kaplan–Meier method was used to determine the 5, 10 year overall survival (OS) rate and relapse free survival rate and Cox Regression test was used to assess the association between patient outcome and age at diagnosis, metastasis status at time of diagnosis, tumor size, nodal involvement and use of chemotherapy. Results: Of these 64 patients, median age at diagnosis was 68 years, majority of patients were white, 13 patients had family history of breast or ovarian cancer (20.3%), four patients tested positive for BRCA2 (6.25). Majority of patients presented painless breast lump. A total of 59 patients (92.2%) had invasive ductal carcinoma, and 31 patients (48.4%) had lymph node involvement at time of diagnosis. A total of 62 patients (96.8%) had M0 disease at time of diagnosis. About 97% of patients had estrogen receptor (ER) positive cancer. Most patients underwent mastectomy (87.5%), 35 patients (54.6%) received adjuvant radiation therapy, 19 patients (30%) received adjuvant chemotherapy and 96.7% of patients received adjuvant hormonal therapy. The median follow-up was 71.5 months (range 6–250 months), 5-year survival rate was 86.9% (95% CI: 74.5–93.6%), 5-year relapse free survival rate was 89.9% (95% CI: 77.4–95.7%) and 10-year survival rate was 58.1% (95% CI: 41.0–71.8%). The presence of distant metastasis at the time of initial diagnosis was the only factor associated with shorter OS (hazard ratio: 22.54, p < 0.0001). Conclusion: Majority of MBC patients present with palpable breast mass and the tumors are almost exclusively hormone receptor positive. Majority of patients present without distant metastasis and received surgical therapy; however, only a small subset of patients received breast conserving surgery for T1 tumor. Almost all patients received adjuvant hormonal therapy. OS and relapse free survival in our cohort is similar to historic reports in female breast cancer.

Clinicopathological features of male patients with breast cancer based on a nationwide registry database in Japan

BACKGROUND

Male breast cancer (MBC) is rare; however, its incidence is increasing. There have been no large-scale reports on the clinicopathological characteristics of MBC in Japan.

METHODS

We investigated patients diagnosed with breast cancer in the Japanese National Clinical Database (NCD) between January 2012 and December 2018.

RESULTS

A total of 594,316 cases of breast cancer, including 3780 MBC (0.6%) and 590,536 female breast cancer (FBC) (99.4%), were evaluated. The median age at MBC and FBC diagnosis was 71 (45-86, 5-95%) and 60 years (39-83) (p < 0.001), respectively. MBC cases had a higher clinical stage than FBC cases: 7.4 vs. 13.3% stage 0, 37.2 vs. 44.3% stage I, 25.6 vs. 23.9% stage IIA, 8.8 vs. 8.4% stage IIB, 1.9 vs. 2.4% stage IIIA, 10.1 vs. 3.3% stage IIIB, and 1.1 vs. 1.3% stage IIIC (p < 0.001). Breast-conserving surgery was more frequent in FBC (14.6 vs. 46.7%, p = 0.02). Axillary lymph node dissection was more frequent in MBC cases (32.9 vs. 25.2%, p < 0.001). Estrogen receptor(ER)-positive disease was observed in 95.6% of MBC and 85.3% of FBC cases (p < 0.001). The HER2-positive disease rates were 9.5% and 15.7%, respectively (p < 0.001). Comorbidities were more frequent in MBC (57.3 vs. 32.8%) (p < 0.001). Chemotherapy was less common in MBC, while endocrine therapy use was similar in ER-positive MBC and FBC. Perioperative radiation therapy was performed in 14.3% and 44.3% of cases.

CONCLUSION

Japanese MBC had an older age of onset, were more likely to be hormone receptor-positive disease, and received less perioperative chemotherapy than FBC.

Male breast cancer: an update

Male breast cancer (MBC) is rare, accounting for less than 1% of all breast cancer but the incidence has increased worldwide. Risk factors include increased longevity, obesity, testicular diseases and tumours, and germline mutations of BRCA2. BRCA2 carriers have 80 times the risk of the general population. Men generally present with breast cancer at an older age compared with women. Histologically, MBC is often of grade 2, hormone receptor positive, HER2 negative, and no special type carcinoma although in situ and invasive papillary carcinomas are common. Reporting and staging are similar to female breast cancer. Metastatic lesions to the male breast do occur and should be differentiated from primary carcinomas. Until recently, MBC was thought to be similar to the usual ER positive post-menopausal female counterpart. However, advances in MBC research and trials have highlighted significant differences between the two. This review provides an up to date overview of the biology, genetics, and histology of MBC with comparison to female breast cancers and differential diagnosis from histological mimics.