Breast Cancer in Men

Male and female disparities in breast cancer epidemiology: A comparative cross-sectional analysis of a Brazilian cohort (2017-2021)

Male breast cancer (MBC) is a rare condition, accounting for approximately 1 % of all breast cancer cases. Nevertheless, the paucity of MBC-specific research has impeded a thorough understanding of MBC. In this study, we aimed to delineate the epidemiological implications of MBC in Brazil and benchmarked it against female breast cancer (FBC). This retrospective study analyzed data from the DATASUS database (2017-2021), which assessed the incidence of breast cancer in both sexes. All statistical analyses were performed using descriptive statistics and inferential methods, with significance set at a 95 % confidence interval. We identified 4,326 (1.7 %) and 233,793 (94.2 %) patients with MBC and FBC, respectively, in Brazil. Despite the general population concentration in the Southeast, MBC cases were more prevalent in the Northeast (p < 0.0004). At breast cancer diagnosis, males were typically older (mean age 59.5 [±10.2] years) than females (mean age 55.7 7 [±9.8] years). MBC was more commonly diagnosed clinically compared with FBC, which was most commonly diagnosed via screening. Surgical diagnostics were twice as likely in males, who also more frequently presented with advanced disease stages (stages III and IV; 72.8 % vs. 59.3 %), leading to a higher rate of mastectomy. Treatment was initiated earlier in males than in females. Although MBC comprises a minority of breast cancer cases, it is more frequently diagnosed at an advanced stage compared with FBC and necessitates aggressive treatment. Our study also underscores the potential benefit of prompt initiation of therapy and need for tailored clinical approaches in patients with MBC.

Clinical characteristics and prognostic factors of male breast cancer in China

Purpose

This study aimed to explore the clinical characteristics of male breast cancer (MBC) patients and the factors influencing their prognosis.

Methods

We conducted a retrospective case series analysis of 117 MBC cases who were treated at Zhejiang Cancer Hospital from 2009 to 2022. Cox proportional hazard model was used to identify prognostic factors of MBC. Nomogram was constructed based on these factors, which was further evaluated by C-index and calibration curves.

Results

A total of 115 MBC cases were finally included in our analyses, with median diagnosis age of 59 years. Of these cases, 80.0% were estrogen receptor (ER) positive, 79.2% were progesterone receptor (PR) positive, 48.7% were human epidermal growth factor receptor 2 (HER2) negative, and 42.6% had Ki67 levels higher than 15%. 108 (93.9%) cases underwent radical mastectomy, while only 3 (2.6%) received breast-conserving surgery. The Logrank test suggested that lymphocyte-to-monocyte ratio (LMR) was negatively associated with both overall survival (OS) and disease-free survival (DFS) of MBC, while platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) were only positively associated with OS (all P-values < 0.05). Multivariate regression analysis showed that age (HR 1.08, 95% CI 1.03-1.13) was significant prognostic factors for OS. Meanwhile, age (HR 1.06, 95% CI 1.02-1.10), histological differentiation grade (poorly differentiated/undifferentiated vs. well-differentiated: HR 2.55, 95% CI 1.05-6.17), and TNM stage (IV vs. I: HR 31.59, 95% CI 6.01-165.93) were also significant prognostic factors for DFS. Nomograms were developed for DFS, with C-indexes of 0.782, indicating good predictive performance.

Conclusion

Increased age, bigger tumor size, higher TNM stage, and lower histological differentiation grade were associated with poor MBC prognosis, and LMR, PLR, and NLR might be potential predictors for MBC prognosis.

Quality of Life in Male Breast Cancer: Prospective Study of the International Male Breast Cancer Program (EORTC10085/TBCRC029/BIG2-07/NABCG)

INTRODUCTION

Prospective data about quality of life (QoL) in men with breast cancer (BC) are lacking. A prospective registry (EORTC10085) of men with all BC stages, including a QoL correlative study, was performed as part of the International Male Breast Cancer Program.

METHODS

Questionnaires at BC diagnosis included the EORTC QLQ-C30 and BR23 (BC specific module), adapted for men. High functioning and global health/QoL scores indicate high functioning levels/high QoL; high symptom-focused measures scores indicate high symptoms/problems levels. EORTC reference data for healthy men and women with BC were used for comparisons.

RESULTS

Of 422 men consenting to participate, 363 were evaluable. Median age was 67 years, and median time between diagnosis and survey was 1.1 months. A total of 114 men (45%) had node-positive early disease, and 28 (8%) had advanced disease. Baseline mean global health status score was 73 (SD: 21), better than in female BC reference data (62, SD: 25). Common symptoms in male BC were fatigue (22, SD: 24), insomnia (21, SD: 28), and pain (16, SD: 23), for which women's mean scores indicated more burdensome symptoms at 33 (SD: 26), 30 (SD: 32), and 29 (SD: 29). Men's mean sexual activity score was 31 (SD: 26), with less sexual activity in older patients or advanced disease.

CONCLUSIONS

QoL and symptom burden in male BC patients appears no worse (and possibly better) than that in female patients. Future analyses on impact of treatment on symptoms and QoL over time, may support tailoring of male BC management.

FAM84B promotes breast cancer tumorigenesis through activation of the NF-κB and death receptor signaling pathways

Breast cancer (BC) occurs predominantly in women and leads to numerous deaths every year. The identification of effective therapeutic targets will benefit BC patients and increase the likelihood of finding a cure. Family with similar sequence 84, member B (FAM84B) has been implicated in the progression of many kinds of cancers, but its function in BC remains to be explored. In this study, online database analysis revealed that FAM84B expression was higher in BC patient tissues, especially in luminal BC tissues, than in the corresponding normal tissues; furthermore, increased FAM84B expression was related to poor prognosis. Additionally, western blot (WB) analysis revealed that the FAM84B protein was highly expressed in luminal BC cell lines compared to normal and basal-like BC cell lines. Moreover, clinical BC patient tissues were collected and subjected to WB and immunohistochemical (IHC) analyses, and the results showed that FAM84B was expressed mainly in luminal BC samples. Therefore, to determine the function of FAM84B in luminal BC cells, luminal BC cell lines with FAM84B knockout and overexpression were generated. In addition, the functions of FAM84B were evaluated in vitro (via cell proliferation, wound healing, colony formation and invasion assays) and in vivo (via a subcutaneous xenograft experiment), and the results showed that FAM84B regulated cell proliferation but not cell invasion. Furthermore, the results of RNA sequencing analysis in ZR-75-1 FAM84B knockout and FAM84B-overexpressing cells showed that FAM84B could affect the TNF signaling pathway. Subsequently, WB analysis of death receptor signaling and immunofluorescence (IF) analysis of NF-κB p65 localization revealed that FAM84B affected death receptor signaling and promoted NF-κB p65 nuclear entry. In conclusion, we found that FAM84B promotes luminal BC tumorigenesis through the activation of the NF-κB and death receptor signaling pathways.

Single-Cell Transcriptional and Epigenetic Profiles of Male Breast Cancer Nominate Salient Cancer-Specific Enhancers

Male breast cancer represents about 1% of all breast cancer diagnoses and, although there are some similarities between male and female breast cancer, the paucity of data available on male breast cancer makes it difficult to establish targeted therapies. To date, most male breast cancers (MBCs) are treated according to protocols established for female breast cancer (FBC). Thus, defining the transcriptional and epigenetic landscape of MBC with improved resolution is critical for developing better avenues for therapeutic intervention. In this study, we present matched transcriptional (scRNA-seq) and epigenetic (scATAC-seq) profiles at single-cell resolution of two treatment naïve MBC tumors processed immediately after surgical resection. These data enable the detection of differentially expressed genes between male and female breast tumors across immune, stromal, and malignant cell types, to highlight several genes that may have therapeutic implications. Notably, MYC target genes and mTORC1 signaling genes were significantly upregulated in the malignant cells of MBC compared to the female counterparts. To understand how the regulatory landscape of MBC gives rise to these male-specific gene expression patterns, we leveraged the scATAC-seq data to systematically link changes in chromatin accessibility to changes in gene expression within each cell type. We observed cancer-specific rewiring of several salient enhancers and posit that these enhancers have a higher regulatory load than lineage-specific enhancers. We highlight two examples of previously unannotated cancer-cell-specific enhancers of ANXA2 and PRDX4 gene expression and show evidence for super-enhancer regulation of LAMB3 and CD47 in male breast cancer cells. Overall, this dataset annotates clinically relevant regulatory networks in male breast tumors, providing a useful resource that expands our current understanding of the gene expression programs that underlie the biology of MBC.

Occupational exposure to organic solvents and breast cancer risk: a systematic review and meta-analysis

Breast cancer is the most common cancer worldwide. Recent studies suggest that organic solvent exposure could be closely related to breast cancer, although the evidence remains controversial. Thus, we evaluated existing epidemiological evidence for the association between occupational solvent exposure and breast cancer. PubMed, Embase, and Cochrane Library were searched to identify published case-control and cohort studies that addressed occupational exposure to organic solvents and breast cancer, up to April, 2021. Meta-analyses using random-effects models were conducted to obtain the pooled odds ratios (OR) and 95% confidence intervals (CI) on the incidence of breast cancer in relation to occupational exposure. The pooled OR of breast cancer among workers exposed to organic solvents overall was 1.18 (95%CI, 1.11 ~ 1.25; I² = 76.3%; 24 studies), compared to those with no exposure. After stratification by menopause and study location, it was revealed that the association between occupational exposure to organic solvents and the risk of breast cancer in postmenopausal women (OR, 1.35; 95% CI, 1.09 ~ 1.67; I² = 73.4%; 7 studies) was significant, and there was also a clear association in workers in Europe (OR, 1.21; 95% CI, 1.12 ~ 1.32; I² = 82.9%; 13 studies). We observed a significant association between occupational exposure to organic solvents and breast cancer in both cohort and case-control studies.

Evaluation of multiple transcriptomic gene risk signatures in male breast cancer

Male breast cancer (BCa) is a rare disease accounting for less than 1% of all breast cancers and 1% of all cancers in males. The clinical management is largely extrapolated from female BCa. Several multigene assays are increasingly used to guide clinical treatment decisions in female BCa, however, there are limited data on the utility of these tests in male BCa. Here we present the gene expression results of 381 M0, ER+ve, HER2-ve male BCa patients enrolled in the Part 1 (retrospective analysis) of the International Male Breast Cancer Program. Using a custom NanoString™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDX®, and MammaPrint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by us previously. We also examined the prognostic value of other risk scores such as the Genomic Grade Index (GGI), IHC4-mRNA and our prognostic 95-gene signature. In this sample set of male BCa, we demonstrated prognostic utility on univariate analysis. Across all signatures, patients whose samples were identified as low-risk experienced better outcomes than intermediate-risk, with those classed as high risk experiencing the poorest outcomes. As seen with female BCa, the concordance between tests was poor, with C-index values ranging from 40.3% to 78.2% and Kappa values ranging from 0.17 to 0.58. To our knowledge, this is the largest study of male breast cancers assayed to generate risk scores of the current commercial and academic risk tests demonstrating comparable clinical utility to female BCa.

Imaging in gynecomastia

BACKGROUND

Gynecomastia (GM) is the benign proliferation of glandular tissue in the male breast. It is a common condition, which may occur physiologically and shows three age peaks during a male's lifespan: infancy, puberty, and senescence. An underlying pathology may be revealed in 45%-50% of adult men with GM, such as aggravating medications, systemic diseases, obesity, endocrinopathies, or malignancy.

OBJECTIVE

To discuss the role of imaging in the evaluation of GM and its contribution to therapeutic decision-making.

MATERIALS/METHODS

The current literature was reviewed through PubMed, Scopus, and CENTRAL electronic databases to identify the best available evidence concerning imaging modalities in patients with GM.

RESULTS

Most male breast lesions can be diagnosed on clinical grounds; however, in certain cases, when physical examination is inconclusive, imaging may be helpful.

DISCUSSION

The main purpose of evaluating a patient with GM is to establish the diagnosis and differentiate true GM from pseudogynecomastia, exclude breast cancer, and detect the possible cause. GM is seen in mammography as a subareolar opacity and three mammographic patterns of GM are described: nodular, dendritic, and diffuse, corresponding to florid GM of early onset, fibrous persistent GM, and GM due to exogenous estrogen administration, respectively. In ultrasound (US), florid GM is depicted as a disk-shaped, hypoechoic area underlying the areola, whereas echogenicity of the lesions increases as fibrosis develops. Data on the use of MRI in the evaluation of the male breast and GM are still limited. Imaging findings can be classified according to the BIRADS (breast imaging reporting and data system) based on their malignant potential.

CONCLUSION

Both mammography and US are sensitive and specific to diagnose GM and distinguish it from breast cancer. When clinical findings are suggestive of malignancy or imaging findings are inconclusive, a histological confirmation should be sought.

Tumor subtypes and survival in male breast cancer

PURPOSE

Male breast cancer is an uncommon disease, and population-based information regarding prognostic factors is limited. Most cases are hormone receptor (HR) positive; however, the association of tumor subtype with overall survival (OS) and breast cancer-specific survival (BCSS) is unclear.

METHODS

Using SEER data, we identified men with invasive breast cancer between 2010 and 2017 with known HR and HER2 status. We examined tumor subtypes by patient characteristics and performed multivariate Cox proportional hazards analyses to determine the associations of each variable with OS and BCSS.

RESULTS

We included 2389 men with a median follow-up of 43 months (IQR 19-68). Median age was 66 years. Tumor subtype distribution was 84.1% HR+/HER2-, 12.7% HR+/HER2+ , 0.8% HR-/HER2+, and 2.3% triple-negative (TN). In univariate analysis, OS at 5 years was 76.5% for HR+/HER2-, 65.1% for HR+/HER2+ , 84.2% for HR-/HER2+, and 48.1% for TN (p < 0.0001). Of all subtypes, TN had the worst BCSS (p < 0.0001). Stage, tumor subtype and race were significantly associated with OS and BCSS in multivariate analysis. Adjusted Cox hazard ratios for OS by tumor subtype with HR+/HER2- as reference were 1.55 for HR+/HER2+ (p = 0.001), 1.1 for HR-/HER2+ (p = 0.888), and 3.59 for TN (p < 0.001).

CONCLUSION

We observed significant differences in survival outcomes by tumor subtype. Poor outcomes among men with HER2+ and TN disease suggest possible under-treatment, aggressive tumor biology, and/or more advanced disease at presentation. Studies to better understand the inferior survival for men with these subtypes are warranted and will likely require international collaboration.

Sex-Based Heterogeneity in the Clinicopathological Characteristics and Prognosis of Breast Cancer: A Population-Based Analysis

Purpose

To better understand the differences in clinicopathological features and prognosis between male breast cancer (MBC) and female breast cancer (FBC).

Material and Methods

Data on patients diagnosed with breast cancer from January 1, 2010, to December 31, 2016, were obtained from the Surveillance, Epidemiology, and End Results database. Selected patients were classified into MBC and FBC, of which population demographics and clinicopathological features at baseline were successively extracted for analysis. Comparative analysis was performed to explore the differences in baseline characteristics, followed by propensity-score matching to calibrate the objective distinctions for adjusted analysis. Survival analysis was carried out to investigate divergences presented in prognosis from the two cohorts, and risk factors for prognosis were successively identified using univariate and multivariate COX regression analyses.

Results

A total of 407341 individuals were eligible, including 3111 MBC (0.7%) and 404230 FBC (99.3%) patients. Comparatively, patients with MBC tended to be older at diagnosis, with a higher confirmation of ductal carcinoma, a higher histological grade, a higher TNM stage, a higher proportion of luminal-like subtype, a higher rate of lung metastasis, a lower incidence of liver involvement, and a lower rate of surgical, radiation, and chemotherapeutic delivery. The overall prognosis of MBC was significantly worse than that of FBC, with a decreasing divergence both in median overall survival (65.5 months vs. 72.7 months, P<0.0001) and median breast cancer-specific survival (75.4 months vs. 77.8 months, P<0.0001). However, these discrepancies were not consistent among patients from different subgroups stratified by molecular subtype, age at diagnosis, or disease stage.

Conclusion

In this study, sex-based heterogeneity in clinicopathological characteristics and prognostic profiles was observed in the overall population of patients with breast cancer and was significantly variable among different subgroups. A male-specific design with reasonable endpoints for a clinical trial protocol will be warranted in the future.

An Approach Based on Mammographic Imaging and Radiomics for Distinguishing Male Benign and Malignant Lesions: A Preliminary Study

Purpose

To develop and validate an imaging-radiomics model for the diagnosis of male benign and malignant breast lesions.

Methods

Ninety male patients who underwent preoperative mammography from January 2011 to December 2018 were enrolled in this study (63 in the training cohort and 27 in the validation cohort). The region of interest was segmented into a mediolateral oblique view, and 104 radiomics features were extracted. The minimum redundancy and maximum relevance (mRMR) and the least absolute shrinkage and selection operator (LASSO) methods were used to exclude radiomics features to establish the radiomics score (rad-score). Mammographic features were evaluated by two radiologists. Univariate logistic regression was used to select for imaging features, and multivariate logistic regression was used to construct an imaging model. An imaging-radiomics model was eventually established, and a nomogram was developed based on the imaging-radiomics model. Area under the curve (AUC) and decision curve analysis (DCA) were applied to assess the clinical value.

Results

The AUC based on the imaging model in the validation cohort was 0.760, the sensitivity was 0.750, and the specificity was 0.727. The AUC, sensitivity and specificity based on the radiomics in the validation cohort were 0.820, 0.750, and 0.867, respectively. The imaging-radiomics model was better than the imaging and radiomics models; the AUC, sensitivity, and specificity of the imaging-radiomics model in the validation cohort were 0.870, 0.824, and 0.900, respectively.

Conclusion

The imaging-radiomics model created by the imaging characteristics and radiomics features exhibited a favorable discriminatory ability for male breast cancer.

The prognostic significance of metastatic pattern in stage IV male breast cancer at initial diagnosis: a population-based study

PURPOSE

Metastatic pattern (MP) is a prognostic factor in women with breast cancer. However, the prognostic significance of MP in male breast cancer patients remains unknown.

METHODS

Using the SEER database, we gathered demographic information and disease characteristics for men diagnosed with de novo metastatic breast cancer from 2010 to 2017. Metastases to bone, brain, liver, and lung were used to define MP (bone-only, visceral, bone and visceral [BV], or other). Statistical analyses were performed to identify associations between overall survival (OS) and MP, as well as other patient and tumor features. We used multivariate logistic regression to evaluate factors associated with sites of metastases.

RESULTS

We included 250 patients. MP distribution was bone = 38.8%, visceral = 14.8%, BV = 33.2%, and other = 13.2%. Median OS for each was bone = 33 months, visceral = 23 months, BV = 20 months, and other = 46 months (p = 0.046). Patients with brain metastases had significantly shorter OS compared with no brain metastases (median OS = 9 months vs. 30 months; p < 0.001). Compared with other subtypes, triple negative had the shortest OS (median 9 months, p < 0.001). Logistic regression modeling revealed that compared with HR+/HER2- breast cancers, HR-/HER2+ had higher odds of liver metastases and triple negative had higher odds of brain metastases. Patients younger than 50 years had a significantly greater risk of developing brain metastases.

CONCLUSIONS

MP and tumor subtype can predict OS outcomes in men with metastatic breast cancer at diagnosis. Brain metastases confer very poor prognosis.

Differential diagnosis of benign and malignant male breast lesions in mammography

PURPOSE

To investigate the mammographic characteristics in discriminating benign and malignant male breast lesions.

METHODS

Male patients with breast lesions detected by preoperative mammography were enrolled in this study from Jan 2011 to Dec 2018. All lesions were confirmed by biopsy and classified into benign group or malignant group. Imaging features included lesions location, lesion type, lesion density, lesion eccentricity, accompanying signs(calcification, nipple retraction, thickened skin and enlarged lymph nodes) were recorded and analysed by statistical methods. The AUC was calculated to assess their diagnostic performance in distinguishing benign and malignant lesions. This model was further validated by 0.632 bootstrap.

RESULTS

A total of 93 men(median age: 60, range 32-81 years) were enrolled, 43 patients in the benign group and 50 patients in the malignant group. In the univariate logistic analysis, age, lesion location, lesion type, lesion density, lesion eccentricity, calcification, nipple retraction and skin thickening were significantly different (p < 0.05). When the lesion showed a mass in mammography, those with a circumscribed margin were likely malignant (p < 0.05). In the multivariate logistic analysis, non-retro-areola lesions (OR: 6.900, 95 % CI: 1.413∼33.691, p < 0.05), eccentric lesions (OR: 14.566, 95 % CI: 2.800∼75.777, p < 0.05), high-density lesions (OR: 11.052, 95 % CI: 2.235∼54.666, p < 0.05), calcification (OR: 12.715 95 % CI: 1.316∼122.848, p < 0.05) and nipple retraction (OR: 24.681, 95 % CI: 2.853∼213.542 p < 0.05) were associated with breast cancer. Those variables were used to build logistic model and the AUC of the imaging model was 0.904. The imaging model was verified by 0.632 bootstrap resampling, and the AUC after 0.632 bootstrap was 0.892.

CONCLUSION

Mammographic characteristics could contribute to distinguishing malignant and benign male breast lesions, and the imaging model showed excellent diagnostic performance, which may help to guide clinical decision-making.

CDK4/6 Inhibitors in Breast Cancer Treatment: Potential Interactions with Drug, Gene, and Pathophysiological Conditions

Palbociclib, ribociclib, and abemaciclib belong to the third generation of cyclin-dependent kinases inhibitors (CDKis), an established therapeutic class for advanced and metastatic breast cancer. Interindividual variability in the therapeutic response of CDKis has been reported and some individuals may experience increased and unexpected toxicity. This narrative review aims at identifying the factors potentially concurring at this variability for driving the most appropriate and tailored use of CDKis in the clinic. Specifically, concomitant medications, pharmacogenetic profile, and pathophysiological conditions could influence absorption, distribution, metabolism, and elimination pharmacokinetics. A personalized therapeutic approach taking into consideration all factors potentially contributing to an altered pharmacokinetic/pharmacodynamic profile could better drive safe and effective clinical use.

Management of hormone receptor-positive, HER2-negative early breast cancer

The majority of breast cancers are diagnosed at an early stage and are hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative. Significant advances have been made in the management of early stage HR-positive, HER2-negative breast cancer, resulting in improved survival outcomes. In this review, we discuss important factors to consider in the management of this disease. In particular, we discuss the role of adjuvant endocrine therapy, specific endocrine therapy agents, the duration of adjuvant endocrine therapy, treatment-related side effects, and the role of genomic assays and other biomarkers when considering treatment recommendations for individuals with HR-positive, HER2-negative early breast cancer. Finally, we address emerging data to individualize therapeutic decision-making and provide future considerations.

BRCA and PALB2 mutations in a cohort of male breast cancer with one bilateral case

INTRODUCTION

Male Breast Cancer (MBC) is a rare disease, about 1% of all breast cancers worldwide and less than 1% of cancers occurring in men. The bilateral male breast cancer (bMBC) is extremely rare. Germline mutations of BRCA1/BRCA2 genes are associated with a significantly increased risk of cancer in MBC; the role of PALB2 remains to be clarified. Our main goal was to provide contribution on characterization of BRCA1/BRCA2 and PALB2 mutations in MBC patients.

METHODS

We observed 28 MBC cases; one of them was a bMBC. Screening for BRCA1, BRCA2 and PALB2 genes was performed on all 28 MBC patients. Mutational analysis was extended to family members of mutated patients.

RESULTS

In our study, the MBC incidence was 5.2% and for bMBC was 3.6%. Mutation analysis showed pathogenic mutations in 11/28 (39.3%) patients; 2/28 (7.1%) displayed a mutation in BRCA1, 8/28 (28.6%) in BRCA2 and 1/28 (3.6%) in PALB2. Out of 11 mutated patients, one (9.1%) reported a double mutation in BRCA2. Personal history of other cancers was reported in 2/28 (7.1%) patients affected by bladder cancer. A first/second degree family history of breast/ovarian and other cancers occurred in 23/28 (82.1%) patients.

CONCLUSION

Our findings indicate BRCA2 as the main MBC susceptibility gene and describe an increased risk of bMBC and bladder cancer in mutated patients. The identification of mutations in MBC susceptibility genes supports the usage of oncology prevention programs in affected patients and their relatives carrying the mutation.

Male breast cancer in the United States: Treatment patterns and prognostic factors in the 21st century

BACKGROUND

Male breast cancer (MBC) is a rare disease for which there is limited understanding of treatment patterns and prognostic factors.

METHODS

Men with TNM stage I to stage III breast cancer diagnosed between 2004 and 2014 in the National Cancer Data Base were included. Trends in treatment modalities were described using the average annual percentage change (AAPC) and estimated using Joinpoint software for the analysis of trends. Kaplan-Meier curves and the multivariate Cox proportional hazards regression model were used to compare survival between subgroups and to identify prognostic factors.

RESULTS

A total of 10,873 MBC cases were included, with a median age at diagnosis of 64 years. Breast-conserving surgery was performed in 24% of patients, and 70% of patients undergoing breast conservation received radiotherapy. Approximately 44% of patients received chemotherapy, and 62% of patients with estrogen receptor-positive disease received endocrine therapy. Oncotype DX was ordered in 35% of patients with lymph node-negative, estrogen receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors. During the study period, there was a significant increase in the rates of total mastectomy, contralateral prophylactic mastectomy, radiotherapy after breast conservation, ordering of Oncotype DX, and the use of endocrine therapy (P < .05). On multivariate analysis, factors found to be associated with worse overall survival were older age, black race, higher Charlson Comorbidity Index, high tumor grade and stage of disease, and undergoing total mastectomy. Residing in a higher income area; having progesterone receptor-positive tumors; and receipt of chemotherapy, radiotherapy, and endocrine therapy were associated with better overall survival.

CONCLUSIONS

Despite the lack of prospective randomized trials in patients with MBC, the results of the current study demonstrated that the treatment of this disease has evolved over the years. These findings further the understanding of the modern treatment and prognosis of MBC, and identify several areas for further research.