Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program

Male breast cancer differs from female breast cancer in molecular features that affect prognoses and drug responses

BACKGROUND

Male breast cancer (MBC) is a rare malignancy with a worse prognosis than female breast cancer (FBC). Current MBC treatment strategies are based on those for FBC. However, molecular differences between MBC and FBC with respect to prognosis and drug responses remain unclear.

METHODS

After controlling for confounding factors with propensity score matching (PSM), differences between MBC and FBC were comprehensively analyzed using many types of data: survival, immune microenvironments, sex hormone responses, drug sensitivity, transcriptomes, genomes, epigenomes, and proteomes.

RESULTS

Overall survival (OS) and cancer-specific survival (CSS) were both worse for MBC than for FBC. Differentially expressed mRNAs were enriched in numerous cancer-related functions and pathways, with SPAG16 and STOX1 being as the most important prognosis-related mRNAs for MBC. Competing endogenous RNA (ceRNA) and transcription factor (TF)-mRNA regulatory networks contain potential prognostic genes. Nine genes had higher mutation frequencies in MBC than in FBC. MBC shows a comparatively poor response to immunotherapy, with five proteins that promote breast cancer progression being highly expressed in MBC. MBC may be more responsive than FBC to estrogen. We detected six United States Food and Drug Administration (FDA)-approved therapeutic target genes as being differentially expressed between MBC and FBC.

CONCLUSION

The poor prognosis of MBC compared to FBC is due to numerous molecular differences and resulting drug responses.

Accuracy of sentinel lymph node biopsy in male breast cancer: Systematic review and meta-analysis

BACKGROUND

Sentinel lymph node biopsy (SLNB) is commonly used in the surgical management of male breast cancer. Contrary to female breast cancer, limited data exist about its performance in male breast cancer. The objective of this systematic review and meta-analysis was to evaluate the SLNB accuracy in male breast cancer.

METHODS

MEDLINE, EMBASE, Web of Science and The Cochrane Library were searched from January 1995 to April 2023 for studies evaluating the SLNB identification rate and false-negative rate in male breast cancer with negative preoperative axillary evaluation and primary surgery. For SLNB false-negative rate, the gold standard was the histology of axillary lymph node dissection (ALDN). Methodological quality was assessed by using the QUADAS-2 tool. Pooled estimates of the SLNB identification rate and false-negative rate were calculated. Heterogeneity of the pooled studies was evaluated using I2 index.

RESULTS

A total of 12 retrospective studies were included. The 12 studies that reported the SLNB identification rate gathered a total of 164 patients; the 5 studies that reported the SLNB false-negative rate gathered a total of 50 patients with a systematic ALND. The pooled estimate of the SLNB identification rate was 99.0%. The SLNB false-negative rates were 0% in the 5 included studies and consequently so as the pooled estimate of the false-negative rate with no heterogeneity.

CONCLUSION

SLNB for male breast cancer, following negative preoperative axillary assessment and primary surgery, appears feasible, consistent, and effective. Our research supports conducting immediate SLNB histological evaluation to facilitate prompt ALND in case of positive results.

Imaging the Male Breast: Gynecomastia, Male Breast Cancer, and Beyond

The number of men undergoing breast imaging has increased in recent years, according to some reports. Most male breast concerns are related to benign causes, most commonly gynecomastia. The range of abnormalities typically encountered in the male breast is less broad than that encountered in women, given that lobule formation rarely occurs in men. Other benign causes of male breast palpable abnormalities with characteristic imaging findings include lipomas, sebaceous or epidermal inclusion cysts, and intramammary lymph nodes. Male breast cancer (MBC) is rare, representing up to 1% of breast cancer cases, but some data indicate that its incidence is increasing. MBC demonstrates some clinical features that overlap with those of gynecomastia, including a propensity for the subareolar breast. Men with breast cancer tend to present at a later stage than do women. MBC typically has similar imaging features to those of female breast cancer, often characterized by an irregular mass that may have associated calcifications. Occasionally, however, MBC has a benign-appearing imaging phenotype, with an oval shape and circumscribed margins, and therefore most solid breast masses in men require tissue diagnosis. Histopathologic evaluation may alternatively reveal other benign breast masses found in men, including papillomas, myofibroblastomas, and hemangiomas. Radiologists must be familiar with the breadth of male breast abnormalities to meet the rising challenge of caring for these patients. ©RSNA, 2024 Supplemental material is available for this article.

An ovine model for investigation of the microenvironment of the male mammary gland

The specific biology of the male breast remains relatively unexplored in spite of the increasing global prevalence of male breast cancer. Delineation of the microenvironment of the male breast is restricted by the low availability of human samples and a lack of characterisation of appropriate animal models. Unlike the mouse, the male ovine gland persists postnatally. We suggest that the male ovine mammary gland constitutes a promising adjunctive model for the male breast. In this study, we evaluate the male ovine mammary gland microenvironment, comparing intact and neutered males. Assessment of the glandular histo-anatomy highlights the resemblance of the male gland to that of neonatal female sheep and confirms the presence of rudimentary terminal duct lobular units. Irrespective of neutered status, cell proliferation in epithelial and stromal compartments is similarly low in males, and cell proliferation in epithelial cells and in the intralobular stroma is significantly lower than in pubertal female sheep. Between 42% and 72% of the luminal mammary epithelial cells in the male gland express the androgen receptor and expression is significantly reduced by neutering. Luminal epithelial cells within the intact and neutered male gland also express oestrogen receptor alpha, but minimal progesterone receptor expression is observed. The distribution of leukocytes within the ducts and stroma is similar to the mammary gland of female sheep and females of other species. Both macrophages and T lymphocytes are intercalated in the epithelial bilayer and are more abundant in the intralobular stroma than the interlobular stroma, suggesting that they may have a protective immunological function within the vestigial glandular tissue of the male sheep. Mast cells are also observed within the stroma. These cells cluster near the glandular tissue and are frequently located adjacent to blood vessels. The abundance of mast cells is significantly higher in intact males compared to neutered males, suggesting that hormone signalling may impact mast cell recruitment. In this study, we demonstrate the utility of the male ovine mammary gland as a model for furthering our knowledge of postnatal male mammary biology.

Screening Mammography for Males With Elevated Breast Cancer Risk, Mutation Carriers, and Gynecomastia

INTRODUCTION

The recommendations for annual mammography for male carriers with gynecomastia are controversial. This study investigated the potential link between gynecomastia and breast cancer in male carriers.

PATIENTS AND METHODS

The database of a tertiary medical center was retrospectively searched for all male patients who underwent at least 1 digital mammography study from 2016 to 2023. Known carriers of a pathogenic variant in a high-risk breast-cancer gene were identified. Patients were stratified by carrier status, diagnosis of breast cancer, and diagnosis of gynecomastia. Data on demographics, hormone profile, and pathology results were compared.

RESULTS

The cohort included 446 men of whom 82 were known carriers. Gynecomastia was diagnosed by mammography in 251 patients: 239/364 noncarriers (66%) and 12/82 carriers (15%) (P < .0001). Breast cancer was found in 21/364 noncarriers (6%) and 6/82 carriers (7%) (P < .6), and in 10/251 patients with gynecomastia (4%) and 17/193 (9%) without gynecomastia (P < .05). Among patients without gynecomastia, the number of breast cancer cases was similar in carriers and noncarriers (P = .3). Among patients with gynecomastia, the rate of breast cancer was higher in carriers (P < .08). On logistic regression analysis, the effect of gynecomastia on carriers was significant (P = .02). The odds ratio for a breast cancer diagnosis was 5.8 in the presence of gynecomastia (95% CI, 1.1-31, P < .04) and 0.52 in the absence of gynecomastia (95% CI, 0.2-1.7, P < .3).

CONCLUSION

Gynecomastia may be associated with an increased risk of breast cancer in carriers. Larger studies are needed to determine whether and when to screen male carriers.

Exploring the One Health Paradigm in Male Breast Cancer

How cancer patterns in humans compare to those of other species remains largely unknown and there is an even bigger knowledge gap for rare cancers like male breast cancer. One Health is a convergence of human and animal healthcare that encourages cross-pollination of medical research uniting human and veterinary medicine. Recognising that breast cancer occurs spontaneously in other male species (e.g. primates, canines, felines), and knowing that no laboratory models exist for male breast cancer, which limits our ability to perform functional studies, we explored the feasibility of applying One Health to breast cancer in men by conducting a narrative review of the topic. Spontaneous development of breast cancer was reported in captive male primates and in companion canines and felines. Some parallels in tumour biology of human male breast cancer with canines and primates were found. The age distribution, pattern of biomarker expression and metastasis were similar, with mammary tumours typically detected after two-thirds of average lifespan. However, instances of triple negative and inflammatory breast cancer, which are rarely observed in human male breast cancer, were found in canines and histological classification was inconsistent between species. These disparities need redressing to enable full exploration of the One Health paradigm in rare cancers.

Stakeholders' experiences and perceptions of male breast cancer:A qualitative evidence synthesis

BACKGROUND

The experiences, physical and mental health and needs of women with breast cancer have been studied in some detail, but there is a lack of discussion of the experiences of stakeholder groups such as men with breast cancer, partners and carers and healthcare professionals. The aim of this study was to explore and understand the experiences and perceptions of male breast cancer stakeholders from diagnosis through to survivorship.

METHODS

We conducted a thematic review of qualitative studies included in a large published scoping review on male breast cancer (reported under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews extension). To be included in a qualitative evidence review, studies had to use qualitative methods for data collection and analysis to capture the perspectives of men with breast cancer, partners or caregivers, and healthcare workers. Key characteristics and findings were extracted and a conceptual coding framework was summarized using thematic analysis.

RESULTS

Out of a total of 310 studies in the research literature (published research articles and gray literature), 15 studies met the inclusion criteria. These studies reported on the experiences of men with breast cancer, partners or caregivers, and healthcare workers, with participant numbers ranging from 2 to 31. A total of 17 descriptive themes (study outcomes) were identified. From these, four high-level analytic themes emerged: (1) Predicament; (2) Emotion; (3) Support; (4) Coping.

CONCLUSIONS

The gender stigma that exists at the patient, healthcare system, and family-society levels largely influences the experiences of the male breast cancer stakeholder population. To address gender inequalities in breast cancer care, healthcare organizations and society at large should remain equally attentive to the needs of male and female breast cancer patients. These needs include reducing healthcare and social stigma, providing gender-specific information and emotional support, and access to support groups.

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.

HER2 Low Expression in Primary Male Breast Cancer

Purpose

The introduction of HER2-targeting antibody drug conjugates (ADCs) offers new treatment options for female breast cancer patients (FBC) expressing low levels of HER2 (HER2 low). No evidence was found that HER2 low describes a new FBC subtype. There is a lack of studies determining the impact of HER2 low in male breast cancer (MBC). In this study, we evaluate the prevalence of HER2 low in primary MBC and correlate the results with patient characteristics.

Patients and Methods

In this study, histological specimens were obtained from 120 male patients diagnosed and treated for primary invasive breast cancer from 1995 to 2022 at Breast Cancer Units in Bergisch Gladbach, Chemnitz, and Zwickau, Germany. HER2 immunostaining and in situ hybridization were performed by central pathology and evaluated based on the ASCO/CAP guidelines. The correlation of expression of HER2 low with tumor biological characteristics and patient outcomes was investigated.

Results

Out of all cases, four patients (3.3%) showed HER2 positivity (3+), 39 (32.5%) patients were classified as HER2 low, 7 (5.8%) were HER2 2+ (no amplification), 32 (26.7%) were HER2 1+, and 77 (64.2%) were classified as HER2 zero. Out of 77 HER2 zero cases, 47 tumors (61.0%) showed incomplete staining, with <10% of tumor cells classified as HER2 ultralow. No statistical correlation between HER2 low and tumor biological characteristics and patients' survival was found.

Conclusion

Our findings show a notable, albeit lower, prevalence of HER2 low expression in primary MBC. However, tumors expressing HER2 low do not show specific tumor biological features to define a new breast cancer subtype in MBC. Our results suggest that a significant number of MBC patients could benefit from ADCs, as shown in FBC. Further studies are required to better understand HER2 low breast cancer, both generally and in MBC.

Adjuvant chemotherapy and survival in males aged 70 years or older with breast cancer: a population-based retrospective study

BACKGROUND

Male breast cancer constitutes a minority of breast cancer diagnoses, yet its incidence has been on the rise in recent decades. However, elderly male breast cancer patients have been inadequately represented in clinical trials, posing challenges in treatment decisions. This study seeks to clarify the efficacy of chemotherapy in this demographic and identify the population most likely to benefit from such intervention.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database, encompassing a total of 1900 male breast cancer patients aged 70 years or older. Among them, 1652 were categorized in the no-chemotherapy group, while 248 were in the chemotherapy group. A multifactorial logistic regression model was employed to investigate the determinants influencing the administration of chemotherapy in elderly male breast cancer patients. Additionally, the multivariate Cox proportional hazards regression model was applied to identify factors associated with outcomes, with overall survival (OS) as the primary endpoint.

RESULTS

Multivariate logistic regression analysis revealed that grade, tumor size, and nodal status were robust predictors for elderly male breast cancer patients receiving chemotherapy. Furthermore, the multivariate analysis demonstrated that chemotherapy conferred benefits compared to the no-chemotherapy group (HR = 0.822, 95% CI: 0.682-0.991, p = 0.040). Stratified analyses indicated that individuals with N+, poorly/undifferentiated grade, and stage II/III disease could derive benefits from chemotherapy. Upon further investigation of progesterone receptor (PR) positive patients, it was found that only stage III patients experienced significant benefits from chemotherapy (HR = 0.571, 95% CI: 0.372-0.875, p = 0.010). Conversely, in PR negative patients, both stage II (HR = 0.201, 95% CI: 0.051-0.792, p = 0.022) and stage III patients (HR = 0.242, 95% CI: 0.060-0.972, p = 0.046) derived benefits from chemotherapy.

CONCLUSION

Adjuvant chemotherapy may benefit certain elderly male breast cancer patients, specifically those with positive lymph node status, poorly/undifferentiated grade, and PR-positive in stage III, as well as PR-negative expression in stage II/III. Given favorable physical tolerance, it is advisable not to hastily dismiss chemotherapy for these elderly male breast cancer patients.

Male ductal carcinoma in situ: diagnosis and management of a rare disease in men

Ductal carcinoma in situ is very rare in male patients, accounting for approximately 5%-7% of all male breast cancers. We present a case of a man in his early 70s who presented with bloody nipple discharge and gynaecomastia and was subsequently diagnosed with ductal carcinoma in situ (DCIS). We discuss his management with surgical resection and the consideration of adjuvant treatment. We also review the existing literature on the presentation, diagnosis and management of DCIS in men.

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.

Nationwide Analysis of Locoregional Management for Ductal Carcinoma In Situ in Males: An NCDB Analysis of the Surgical Approach to DCIS in Males

BACKGROUND

Limited data exist regarding the optimal locoregional approach for males with ductal carcinoma in situ (DCIS). This study examined trends in management and survival for males with DCIS.

METHODS

The National Cancer Database (NCDB) was queried for males with a diagnosis of DCIS from 2006 to 2017. Patients were categorized by locoregional management. Continuous variables were evaluated by Kruskal-Wallis and categorical variables by chi-square or Fisher's exact test. Univariable and multivariable logistic regressions were performed to evaluate for predictors of patients receiving partial mastectomy (PM) with radiation. Survival was analyzed by Kaplan-Meier.

RESULTS

Between 2006 and 2017, 711 males with DCIS were identified. Most received mastectomy alone (57.1%). No change was observed in management approach from 2006 to 2017. Patients who underwent mastectomy alone were mostly hormone-positive (95.9% were estrogen-positive, 90.9% were progesterone-positive), although this cohort was least likely to receive hormone therapy (17.2%). Among those who underwent PM with radiation, only 61% of those who were hormone-positive received hormone therapy. Univariable analysis demonstrated that those of black race had lower odds of receiving PM with radiation (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.36-0.84), which persisted in the multivariable analysis with control for age and tumor size (OR, 0.32; 95% CI, 0.15-0.67). Overall survival did not differ significantly between the four treatment methods (p = 0.08).

CONCLUSIONS

The management approach to male DCIS did not change from 2006 to 2017. Survival did not differ between treatment methods. Demographic and clinicopathologic features, including race, may influence locoregional treatments received, and further studies are needed to further understand this.

Clinicopathological Features and Treatment Outcomes of Male Breast Cancer in Pakistani Population: A 10-Year Retrospective Cross-Sectional Study

Background

Male breast cancer (MBC) accounts for 1% of global breast cancer cases. On account of its rarity, very few prospective clinical trials have been carried out on MBC. Pakistan has the highest incidence of breast cancer in Asia, but very limited data are available on MBC.

Objectives

The objective is to determine the clinicopathological characteristics and treatment patterns of MBC in Pakistani population.

Design

This is a retrospective cross-sectional study.

Methods

A retrospective cross-sectional study carried out using the cancer database of Shaukat Khanum Memorial Cancer Hospital & Research Center. Men with a histologically proven breast cancer, stage 0 to III disease and requiring surgical intervention were included. The Kaplan-Meier curve and log-rank test were used for survival analysis.

Results

Sixty-eight patients with MBC were included with a median age at diagnosis of 55 years. Most patients were stage II (47.1%). Invasive ductal carcinoma (IDC) was the commonest type (89.7%). Estrogen receptor (ER), progesterone receptor (PR), and Her-2 receptor positivity were 92.6%, 86.8%, and 32.4%, respectively. Mastectomy was performed in 95.6% of the cases. Neoadjuvant and adjuvant chemotherapy was administered in 25 (36.8%) and 26 (38.2%) patients, respectively. Fifty-five (80.9%) patients received adjuvant radiotherapy. Most of the patients (89.7%) received tamoxifen. The 5-year overall and disease-free survival was 88.2% and 80.9%, respectively. Patients receiving neoadjuvant chemotherapy had a better overall and disease-free survival (P = .025).

Conclusions

Male breast cancer occurs at a relatively earlier age in Pakistani population as compared with Western men. Mastectomy is the preferred surgical option for MBC on account of the advanced disease and delayed presentation. Neoadjuvant chemotherapy has a statistically significant effect on overall and disease-free survival, but in spite of these benefits, it remains underutilized.

Experiences and perceptions of men following breast cancer diagnosis: a mixed method systematic review

BACKGROUND

Men with breast cancer experience unique physical and emotional challenges. However, a thorough understanding of these experiences including the psychosocial effects and supportive care needs have received less attention. In some settings, men with breast cancer experience stigma within the healthcare system and their care needs are not prioritised. This influences the level of professional support offered, consequently worsening their health and well-being outcomes. This review explored the variabilities in the experiences and treatment modalities of male breast cancer (MBC) across different contexts.

METHODS

All primary study designs including qualitative, quantitative, and mixed methods studies that reported on the experiences, treatment approaches and outcomes of MBC were included in this systematic review. Six databases (Embase, Medline, PsycINFO, Global Health, CINAHL and Web of Science) were searched for articles from January 2000 to September 2023. A results-based convergence synthesis was used for data analysis and reported using PRISMA guidelines.

RESULTS

Of the studies screened (n = 29,687), forty-four fulfilled the predetermined criteria and were included. Our findings relating to the experiences and treatment approaches of MBC are broadly themed into three parts. Theme 1-Navigating through a threat to masculinity: describes how males experienced the illness reflecting on detection, diagnosis, coming to terms with breast cancer, and disclosure. Theme 2- Navigating through treatment: captures the experiences of undergoing breast cancer treatment/ management following their diagnosis. Theme 3-Coping and support systems: describes how MBC patients coped with the disease, treatment process, aftercare/rehabilitative care, and the available support structures.

CONCLUSIONS

Men experience a myriad of issues following a breast cancer diagnosis, especially with their masculinity. Awareness creation efforts of MBC among the public and healthcare practitioners are urgently required, which could change the perception of men in promoting early diagnosis, adherence to treatments, post-treatment monitoring, oncological results and a better quality of life. Considerations for training, education and development of specialised guidelines for healthcare practitioners on MBC would provide the necessary knowledge and skills to enhance their practice through the adoption of person-centred and male-specific care strategies. Professional care intervention and support for MBC should not end after the diagnosis phase but should extend to the entire treatment continuum and aftercare including future research focusing on MBC specific clinical trials.

TRIAL REGISTRATION

PROSPERO Registration No. CRD42021228778.

Optical Emission Spectroscopy for the Real-Time Identification of Malignant Breast Tissue

Breast conserving resection with free margins is the gold standard treatment for early breast cancer recommended by guidelines worldwide. Therefore, reliable discrimination between normal and malignant tissue at the resection margins is essential. In this study, normal and abnormal tissue samples from breast cancer patients were characterized ex vivo by optical emission spectroscopy (OES) based on ionized atoms and molecules generated during electrosurgical treatment. The aim of the study was to determine spectroscopic features which are typical for healthy and neoplastic breast tissue allowing for future real-time tissue differentiation and margin assessment during breast cancer surgery. A total of 972 spectra generated by electrosurgical sparking on normal and abnormal tissue were used for support vector classifier (SVC) training. Specific spectroscopic features were selected for the classification of tissues in the included breast cancer patients. The average classification accuracy for all patients was 96.9%. Normal and abnormal breast tissue could be differentiated with a mean sensitivity of 94.8%, a specificity of 99.0%, a positive predictive value (PPV) of 99.1% and a negative predictive value (NPV) of 96.1%. For 66.6% patients all classifications reached 100%. Based on this convincing data, a future clinical application of OES-based tissue differentiation in breast cancer surgery seems to be feasible.

Treatments Targeting the Androgen Receptor and Its Splice Variants in Breast Cancer

Breast cancer is a major cause of death worldwide. The complexity of endocrine regulation in breast cancer may allow the cancer cells to escape from a particular treatment and result in resistant and aggressive disease. These breast cancers usually have fewer treatment options. Targeted therapies for cancer patients may offer fewer adverse side effects because of specificity compared to conventional chemotherapy. Signaling pathways of nuclear receptors, such as the estrogen receptor (ER), have been intensively studied and used as therapeutic targets. Recently, the role of the androgen receptor (AR) in breast cancer is gaining greater attention as a therapeutic target and as a prognostic biomarker. The expression of constitutively active truncated AR splice variants in breast cancer is a possible mechanism contributing to treatment resistance. Therefore, targeting both the full-length AR and AR variants, either through the activation or suppression of AR function, depending on the status of the ER, progesterone receptor, or human epidermal growth factor receptor 2, may provide additional treatment options. Studies targeting AR in combination with other treatment strategies are ongoing in clinical trials. The determination of the status of nuclear receptors to classify and identify patient subgroups will facilitate optimized and targeted combination therapies.

Male Breast Cancer: a Review on Diagnosis, Treatment, and Survivorship

PURPOSE OF REVIEW

Male breast cancer is a relatively uncommon and rare disease that is often managed based on evidence adopted from trials pertaining to female breast cancer due to low accrual rates or exclusion of males. This is despite the known differences in the biology and epidemiology of this condition. This review provides an update regarding the management and surveillance of male breast cancer.

RECENT FINDINGS

Men with breast cancer tend to undergo more extensive surgery in the breast and axilla. The outcomes of male breast cancer compared to a similar subtype of female breast cancer appear worse when matched for stage. Systemic therapies remain predominantly based on recommendations for female breast cancer, although tamoxifen is the more optimal endocrine therapy for men than women. Surveillance with mammograms is recommended for patients harboring a breast cancer susceptibility gene but is otherwise not advised for men who have undergone a mastectomy. Notably, the role of other imaging modalities, including ultrasound and magnetic resonance imaging, is minimal. Although the focus on survivorship care among men is low, it is abundantly clear that this is a stigmatizing diagnosis for men, and they suffer from long-term physical and psychological sequelae following a diagnosis and treatment of breast cancer. In summary, providing more gender-inclusive care and advocating for increased representation of men in prospective breast cancer studies and clinical trials may help improve outcomes and provide enhanced support for this population.

Clinicopathological analysis of 38 male patients diagnosed with breast cancer

BACKGROUND

Male breast cancer (MBC) accounts for one percent of all breast cancers. Due to the lack of awareness and routine screening programs, most patients present with systemic disease at the time of diagnosis with low overall survival.

OBJECTIVES

This study aims to investigate the prognostic factors of male breast cancer and its correlation with established prognostic parameters and patient outcomes.

METHODS

Thirty-eight male breast cancer patients are identified from the MKA Breast Cancer Clinic database, and their corresponding clinical and pathological characteristics are obtained. Cut-off values of 1% and 10% are applied to further classify ER and PR results.

RESULTS

Older men are more likely to develop MBC than younger men and are more likely to have spread to axillary lymph nodes. Invasive ductal carcinoma is a more common histologic type in MBC. All the tested patients have ER and PR positivity. Distant metastasis developed in 17/38 (44.7%) patients. Bone metastasis is seen commonly in metastatic MBC.

CONCLUSIONS

According to our cohort, MBC is seen in older males, presents in later stages, and shows hormone receptor positivity and a tendency to bone involvement. MBC is a heterogenous but distinct biological entity requiring a specific clinical and pathological approach.

Clinicopathological features and prognostic analysis of HER2 low and fibrotic focus in HER2-negative breast cancer

OBJECTIVE

The aim of this study is to evaluate the clinicopathological features and prognostic significance of HER2 low, fibrotic focus (FF), and tumor-infiltrating lymphocytes (TILs) in patients with HER2-negative breast cancer.

METHODS

We retrospectively reviewed the data of 293 patients with HER2-negative, stage I-II, invasive breast cancer of non-specific types. The HER2-negative cases were classified into HER2 low and HER2 0. Digital analysis of hematoxylin-eosin stained whole slide images was used to evaluate the FF expression. TILs were also evaluated using the Whole Slide Image. Furthermore, the association between HER2 low, FF, and TILs as well as their prognostic significance were analyzed.

RESULTS

The study cohort included 178 cases (60.8%) with HER2 low and 115 cases (39.2%) with HER2 0. Older age, lower Nottingham histological grade (NHG), estrogen receptor (ER) positivity, progesterone receptor (PR) positivity, and hormone receptor (HR) positivity were all associated with HER2 low. FF was correlated with older age, intermediate and low NHG, vascular invasion, HR positivity, HER2 low status, high Ki67 expression, and low TILs. Univariate survival analysis showed that FF was significantly associated with shorter progression-free survival (PFS). Stratified analysis indicated that in the HR-negative and HR-positive groups, HER2 status and TILs did not affect PFS. DFS was longer in patients without FF compared to those with FF in the HR-positive (hazard ratio [HR] = 0.313) and HER2 low (HR = 0.272) groups. DFS was also significantly longer in patients without FF compared to those with FF in the HR-negative (HR = 0.069) and HER2 0 groups (HR = 0.129).

CONCLUSION

The results indicated that the HER2 low status and the TILs expression did not impact prognosis. However, patients with FF exhibited distinct biological characteristics and prognostic significance, particularly in the HR-negative and HER2 0 groups. This provides a rationale for accurate diagnosis and treatment of HER2-negative breast cancer.

In search of zebras: Critical analysis of the rarity of perineural breast cancer spread to the brachial plexus in men

BACKGROUND

Perineural spread (PNS) of breast cancer to the brachial plexus is rare, with reports limited to cases only in female patients. This study aimed to determine the incidence of PNS in male compared with female patients.

METHODS

Adult breast cancer patients referred to a single institution between 1994 and 2022 were retrospectively reviewed for imaging or biopsy-confirmed cases of PNS to the brachial plexus. Two independent reviewers of articles published in any language between 1990 and 2022 in PubMed, Scopus, Embase, and Google Scholar performed a systematic literature review.

RESULTS

Of the 10,466 patients with breast cancer (10,355 female, 111 male) referred to a single institution, there were 42 female patients with PNS to the brachial plexus for an estimated incidence of 0.4%. In the same time period, there were 111 male patients treated for breast cancer, including 88 patients with Klinefelter's syndrome (KS); however, there were no cases of male patients with PNS. A systematic review of the world's literature did not identify male patients with PNS to the brachial plexus.

CONCLUSIONS

There is a lack of any reported cases of PNS of breast cancer to the brachial plexus in men or patients with KS, who have a much higher incidence of breast cancer. This may reflect either the compounding rarity of these two events or point toward a distinct hormonally-driven link between breast cancer and PNS, highlighted by the disparity in PNS incidence in men and women.

Breast cancer cells are sensitized by piperine to radiotherapy through estrogen receptor-α mediated modulation of a key NHEJ repair protein- DNA-PK

BACKGROUND

Non-homologous end joining, an important DNA-double-stranded break repair pathway, plays a prominent role in conferring resistance to radiotherapeutic agents, resulting in cancer progression and relapse.

PURPOSE

The molecular players involved in the radio-sensitizing effects of piperine and many other phytocompounds remain evasive to a great extent. The study is designed to assess if piperine, a plant alkaloid can alter the radioresistance by modulating the expression of non-homologous end-joining machinery.

METHODS AND MATERIALS

Estrogen receptor-positive/negative, breast cancer cells were cultured to understand the synergetic effects of piperine with radiotherapy. Cisplatin and Bazedoxifene were used as positive controls. Cells were exposed to γ- radiation using Low Dose gamma Irradiator-2000. The piperine effect on Estrogen receptor modulation, DNA-Damage, DNA-Damage-Response, and apoptosis was done by western blotting, immunofluorescence, yeast-based-estrogen-receptor-LacZ-reporter assay, and nuclear translocation analysis. Micronuclei assay was done for DNA damage and genotoxicity, and DSBs were quantified by γH2AX-foci-staining using confocal microscopy. Flow cytometry analysis was done to determine the cell cycle, mitochondrial membrane depolarization, and Reactive oxygen species generation. Pharmacophore analysis and protein-ligand interaction studies were done using Schrodinger software. Synergy was computed by compusyn-statistical analysis. Standard errors/deviation/significance were computed with GraphPad prism.

RESULTS

Using piperine, we propose a new strategy for overcoming acquired radioresistance through estrogen receptor-mediated modulation of the NHEJ pathway. This is the first comprehensive study elucidating the mechanism of radio sensitizing potential of piperine. Piperine enhanced the radiation-induced cell death and enhanced the expression and activation of Estrogen receptor β, while Estrogen receptor α expression and activation were reduced. In addition, piperine shares common pharmacophore features with most of the known estrogen agonists and antagonists. It altered the estrogen receptor α/β ratio and the expression of estrogen-responsive proteins of DDR and NHEJ pathway. Enhanced expression of DDR proteins, ATM, p53, and P-p53 with low DNA-PK repair complex (comprising of DNA-PKcs/Ku70/Ku80), resulted in the accumulation of radiation-induced DNA double-stranded breaks (as evidenced by MNi and γH2AX-foci) culminating in cell cycle arrest and mitochondrial-pathway of apoptosis.

CONCLUSION

In conclusion, our study for the first time reported that piperine sensitizes breast cancer cells to radiation by accumulating DNA breaks, through altering the expression of DNA-PK Complex, and DDR proteins, via selective estrogen receptor modulation, offering a novel strategy for combating radioresistance.

Outcomes of the patients with metastatic male breast cancer

BACKGROUND

The goal of this research is to investigate the clinical characteristics and prognosis of men with metastatic breast cancer (mMBC).

METHODS

A retrospective analysis of the data of 28 patients was conducted. Kaplan-Meier and Cox regression analyses were used to assess overall survival (OS) and prognostic variables.

RESULTS

At the time of diagnosis, the median age was 57 years (range 26-86). The most prevalent pathological subtype was invasive ductal carcinoma (92.6%). HER2 positivity was 21.6% in patients, with estrogen and progesterone receptor positivity at 96.4% and 71.4%, respectively. Bone-75%, lung-39.3%, brain-21.4%, and adrenal gland-10.7% were the most prevalent metastatic sites. Trastuzumab-based chemotherapy was given to six patients. During the study period, 14 patients (or half) died. All patients had a median OS of 42.6 months (range: 21.6-63.7). The OS rates after 1, 3, and 5 years were 95.7%, 54.2%, and 36.6%, respectively. The number of metastatic locations (P = 0.045), brain metastasis (P = 0.033), and a history of regular alcohol intake (P = 0.008) were all shown to be statistically significant factors affecting OS in univariate analysis. However, multivariate analysis did not support the findings. In addition, we discovered that trastuzumab-based therapy and de-novo metastatic disease had no effect on OS for mMBC.

CONCLUSIONS

The data on mMBC is restricted because of its rarity. The prognosis of mMBC was shown to be poor in this investigation. Despite the small number of patients, we discovered that in univariate analysis, having brain metastases, the number of metastatic locations, and a history of alcohol intake may be prognostic factors.

FDA Approval Summary: Ribociclib Indicated for Male Patients with Hormone Receptor-Positive, HER2-Negative Advanced or Metastatic Breast Cancer

On December 10, 2021, the FDA expanded the indications for ribociclib to include male patients for the treatment of hormone receptor-positive, HER2-negative advanced or metastatic breast cancer. Ribociclib is now indicated in combination with an aromatase inhibitor (AI) as initial endocrine-based therapy in adult patients, or with fulvestrant as initial endocrine-based therapy or following disease progression on endocrine therapy (ET), in postmenopausal women or in men. The efficacy of ribociclib + AI for male patients was primarily based on previous favorable benefit-risk assessments of ribociclib from MONALEESA-2 and MONALEESA-7 trials, and supported by COMPLEEMENT-1, an open-label, single-arm, multicenter clinical trial, in which 39 male patients (n = 3,246 total patients) received ribociclib + letrozole + goserelin/leuprolide. The overall response rate (ORR) based on confirmed responses in male patients with measurable disease at baseline was 46.9% [95% confidence interval (CI), 29.1-65.3], consistent with an ORR of 43.6% (95% CI, 41.5-45.8) in the overall population. Overall, adverse reactions occurring in male patients were similar to those occurring in female patients treated with ribociclib + ET. The efficacy of ribociclib + fulvestrant for male patients was primarily based on the previous findings of a favorable benefit-risk assessment from the MONALEESA-3 trial, supported by FDA review of clinical data of a limited number of male patients treated in clinical practice receiving ribociclib + fulvestrant. The known mechanism of action, biologic rationale, and clinical information available adequately demonstrate that the efficacy and safety of ribociclib + AI/fulvestrant are similar in male and female patients. This article summarizes the FDA's decision-making and data supporting the approval of ribociclib in male patients with breast cancer, and discusses regulatory insights.

Risk factors for male breast cancer

Male breast cancer (MBC) presents problems with identification of high-risk groups. Risk factors include hepatic dysfunction, high ambient working temperature, exposure to exhaust fumes and obesity, but none identify a group with a high absolute number of MBC cases. The two significant cohorts are BRCA2 mutation carriers and individuals with Klinefelter's syndrome (KS), responsible for up to 15% of cases. Since >90% of male tumours are ER+ve, endocrine intervention is logical with the likely agent being tamoxifen. In terms of an acceptable endocrine agent, compliance studies. Compliance studies indicate that men do not tolerate tamoxifen well because of side-effects. Although certain groups with an increased risk of MBC can be identified, the absolute number of cases is small so, at present, a meaningful prevention study is not an option.

Evaluation of Male Breast Cancer and the Application of Sentinel Lymph Node Biopsy: A Multicenter Retrospective Study

Sentinel lymph node biopsy (SLNB) is currently used as a routine treatment for patients with breast cancer. However, it may not be applicable for patients with male breast cancer (MBC), because they have notably different clinicopathological features from those occurring in females. There is a lack of evidence of SLNB application and safe exemption from axillary lymph node dissection (ALND) in patients with MBC. This study aimed to evaluate the application of SLNB to provide information for the standardized treatment of patients with MBC. The MBC patient records from 4 institutions ranging from January 2001 to November 2020 were retrospectively reviewed. There were 220 patients with MBC with a median age of 60 (range 24-88) years and an average tumor size of 2.3 cm (range 0.5 cm-6.5 cm). Sixty-six percent of patients underwent SLNB, and 39% of them showed positive results. A total of 157 patients underwent ALND, while only half of them had positive nodes, causing unnecessary complications. For patients in the clinical early stage, we found that the SLNB showed a noninferiority to the ALND treatment in DFS (P = .18) and OS (P = .055). In conclusion, there are certain obstacles to the broad application of SLNB due to the lower proportion of patients with clinically negative lymph nodes. However, it is undeniable that SLNB can safely and effectively exempt patients with MBC at early stage with clinically negative nodes from ALND to reduce subsequent complications. It is still an ideal criterion for the axillary staging of patients with MBC.

Male Breast: A Review of the Literature and Current State of the Art of Diagnostic Imaging Work-Up

Pathological conditions affecting the male breast (MB) share some similarities with those found in women, while others are specific to men. The first part of this review provides an overview of MB disorders, exploring the most common types of MB diseases. The second part then emphasizes the state-of-the-art approaches proposed in the literature for screening and follow-up with MB cancer patients, which highlights the importance of tailored strategies for diagnosis, follow-up, and identifying high-risk populations. Considering the increasing attention in recent years on the topic, transgender individuals are also included in this review. Together with the MB, it is an understudied category thus far. This review aims to raise awareness among radiologists that MBs should be approached differently from female breasts, contributing to the advancement of medical knowledge, improving patient outcomes, and promoting early detection of MB disorders. The review also provides an update on breast cancer and screening in the transgender population.

Unfolding the role of the PI3K/AKT/MTOR pathway in male breast cancer: A pragmatic appraisal

Breast cancer in men is rare, but a relevant public health issue, yielding a 25% higher risk of mortality comparing to female counterparts. The representation of males in clinical trials has been scarce and treatment decisions are based mainly on extrapolations from data in females. In the setting of estrogen-dependent metastatic disease, the use of everolimus has been seldom reported, although the PI3K/AKT/mTOR pathway seems to be a critical oncogenic driver. This paper dissects hallmark biological features of ER+/HER2-advanced male breast cancer, setting a comprehensive basis to promote personalized care, focusing on the potential of targeting the PI3K/AKT/mTOR pathway.

Moderate Intensity Exercise Reduces Side Effects of Cancer Therapy and Maintains Cardiorespiratory Fitness in Male Breast Cancer Patients: Findings from the BRECA Male Crossover Study

Introduction

There is growing evidence that aerobic exercise mitigates cancer therapy-related side effects and improves cardiorespiratory fitness (CRF). However, to the best of our knowledge, no exercise study has been conducted in male breast cancer (MBC) patients. The aim of this study was to investigate the feasibility and efficacy of different exercise intensities on CRF and self-reported questionnaire items in MBC patients.

Methods

Twenty-two MBC patients (60 ± 9 years) participated in this randomized crossover study. After completion of medical treatment, MBC patients were randomly assigned to either moderate (40-50% of heart rate [HR] max. and self-perceived exertion: 11) or vigorous (70-80% of HR max. and self-perceived exertion: 15) exercise intensity during the first 3 months of the study. After a 1-month washout period, participants switched group assignments. Primary endpoints were CRF and questionnaire items.

Results

We observed a dropout rate of 36% over 7 months, with the number of participants decreasing from 22 to 14. The results showed significant improvements in "Physical Function" (p = 0.037) and "Social Function" (p = 0.016) after moderate training. A non-significant improvement was also observed in "Breast Symptoms" (p = 0.095), but there was no change in "Fatigue" (p = 0.306). There were no differences observed in cardiovascular fitness (V̇O2 peak) between the treatment groups.

Conclusion

This study emphasizes the effectiveness of exercise intervention for an exceedingly rare cancer, highlighting the vital role of moderate intensity aerobic exercise in mitigating treatment side effects. Despite minimal peak V̇O2 differences, both exercise protocols adequately sustain CRF. Future studies are imperative to design optimized, sex-specific rehabilitation strategies tailored to the unique requirements of MBC patients, advancing our understanding of this under explored realm.

Immunohistochemistry-derived subtypes of breast cancer distribution in four regions of Ethiopia

Purpose

Different biological characteristics, therapeutic responses, and disease-specific outcomes are associated with different molecular subtypes of breast cancer (BC). Although there have been different studies on BC in the Ethiopian capital city of Addis Ababa, there have been few studies in other parts of the nation, and none have evaluated biological characteristics in other locations in the context of the extensive ethnic and genetic diversity found in Ethiopia. This study was carried out to evaluate the distribution of immunohistochemistry (IHC) subtypes of BCs throughout four Ethiopian regions.

Methods

A total of 227 formalin-fixed paraffin-embedded (FFPE) tissue blocks were collected from tertiary hospitals in four Ethiopian regions between 2015 and 2021. The IHC staining was performed for subtyping, ER, PR, HER2, and Ki-67 proliferation markers.

Results

The mean age at diagnosis was 43.9 years. The percentage of ER and PR-negative tumors were 48.3% and 53.2%, respectively. The IHC subtypes showed the following distribution: 33.1% triple-negative breast cancer (TNBC), 27.6% luminal B, 25.2% luminal A, and 14.1% HER2 enriched. In multiple logistic regression analysis, grade III and HER2 positivity were associated with larger tumor size, and also originating from Jimma compared to Mekele.

Conclusion

Patients with ER-negative, PR-negative, and TNBC were found in 48.3%, 53.2%, and 33.1% of cases, respectively, showing that half the patients could potentially benefit from endocrine treatment. A considerably high prevalence of TNBC was reported in our study, demanding additional research that includes genetic predisposition factors. Additionally, aggressive tumors were found in a high percentage of younger age groups, which must be considered when planning personalized treatment strategies.

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.

Real world data on the demographic and clinicopathological profile and management of patients with early-stage HER2-positive breast cancer and residual disease treated with adjuvant trastuzumab emtansine (KARMA study)

INTRODUCTION

Trastuzumab emtansine (T-DM1) significantly improves invasive disease-free survival and reduces the risk of recurrence in patients with HER2-positive early breast cancer (EBC) with residual disease (RD). The KARMA study aimed to describe the characteristics and management of these patients in clinical practice in Spain.

MATERIAL AND METHODS

We conducted a multicentre retrospective study in patients with HER2-positive EBC with RD following neoadjuvant treatment (NeoT) and who had received ≥1 dose of T-DM1 as adjuvant treatment. The primary endpoint was the evaluation of sociodemographic and clinicopathological characteristics of these patients.

RESULTS

A total of 114 patients were included (March-July 2020). At diagnosis, most tumours were infiltrating ductal carcinoma (IDC) (93.9 %), grade 2 (56.1 %), and hormone receptor (HR)-positive (79.8 %). Over 75 % of patients had disease in operable clinical stages (T1-3 N0-1). In the neoadjuvant setting, 86.8 % of patients received trastuzumab plus pertuzumab, and 23.6 % achieved radiological complete response. Breast-conserving surgery was performed in 55.8 % of patients. Surgical specimens showed that 89.5 % of patients had IDC, 49.1 % grade 2, 84.1 % HR-positive, and 8.3 % HER2-negative disease. Most patients had RD classified as RCB-II and Miller/Payne grade 3/4. Grade 3 treatment-related adverse events (trAEs) occurred in 5.3 % of patients. No grade 4/5 AEs occurred. Over 95 % of patients were free of invasive-disease during T-DM1 adjuvant treatment.

CONCLUSION

The KARMA study describes the characteristics of patients with HER2-positive EBC with RD after NeoT and the real-life management of a T-DM1 adjuvant regimen, which showed a manageable safety profile in line with the KATHERINE trial data.

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.

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.

Clinicopathologic characteristics and prognostic factors in patients with male breast cancer: A single tertiary center experience

BACKGROUND

The goal of this study was to assess the clinicopathologic characteristics and prognostic variables in men with breast cancer (BC).

METHODS

Clinical features, pathological characteristics, stage at diagnosis, and therapy data were noted. Survival analysis was performed using the log-rank technique and Cox regression model.

RESULTS

Eighty patients were included in the study. In 31% of the individuals, BRCA (BReast CAncer genes 1 and 2) mutations were identified. The estrogen receptor (ER) positivity ratio was 93.6%, whereas the progesterone receptor (PR) positivity ratio was 74.4%. In 16.9% of the cases, HER2 overexpression was found. The median survival time was 120.9 months (70.3-171.5), and the five-year overall survival (OS) ratio was 74.9%. In univariate analysis, BRCA mutation status had no effect on OS (P = 0.50). CA15-3 levels (P = 0.03) at diagnosis and history of smoking (P = 0.03) were significantly linked with OS. However, the multivariate analysis could not confirm these results.

CONCLUSIONS

We found that BRCA mutation, body mass index, a history of smoking, and alcohol consumption did not affect the OS in this research.

Treatments for breast cancer in men: late effects and impact on quality of life

PURPOSE

Male breast cancer accounts for approximately 1% of all breast cancer diagnoses. Unfortunately, a lack of information exists regarding late effects of breast cancer treatment in men.

METHODS

An online survey directed towards male breast cancer patients was distributed via social medial and emails from June to July 2022. Participants were asked about their disease characteristics, treatments and side effects from the disease or treatment. Patients and treatment variables were reported via descriptive statistics. Univariate logistic regression was performed to evaluate associations between different treatment variables and outcomes expressed by odds ratio.

RESULTS

A total of 127 responses were analyzed. Median age of the participants was 64 years (range 56-71 years). A total of 91 participants (71.7%) revealed they experienced late effects secondary to their cancer or cancer treatment. The most concerning physical and psychological symptoms reported were fatigue and fear of recurrence respectively. Axillary lymph node dissection was associated with swollen arm and with difficulty in arm or shoulder movement. Systemic chemotherapy was related to bothersome hair loss and changes on interest in sex; and endocrine therapy was associated with feeling less masculine.

CONCLUSION

Our study showed that men suffer several late effects from treatments for breast cancer. Lymphedema, difficulty with arm and shoulder movement, sexual dysfunction and hair loss should be discussed with males as it can be distressing for some patients and decrease their quality of life.

Multigene Panel Sequencing Identifies a Novel Germline Mutation Profile in Male Breast Cancer Patients

Even though male breast cancer (MBC) risk encompasses both genetic and environmental aetiologies, the primary risk factor is a germline pathogenic variant (PV) or likely pathogenic variant (LPV) in BRCA2, BRCA1 and/or PALB2 genes. To identify new potential MBC-specific predisposition genes, we sequenced a panel of 585 carcinogenesis genes in an MBC cohort without BRCA1/BRCA2/PALB2 PV/LPV. We identified 14 genes carrying rare PVs/LPVs in the MBC population versus noncancer non-Finnish European men, predominantly coding for DNA repair and maintenance of genomic stability proteins. We identified for the first time PVs/LPVs in PRCC (pre-mRNA processing), HOXA9 (transcription regulation), RECQL4 and WRN (maintenance of genomic stability) as well as in genes involved in other cellular processes. To study the specificity of this MBC PV/LPV profile, we examined whether variants in the same genes could be detected in a female breast cancer (FBC) cohort without BRCA1/BRCA2/PALB2 PV/LPV. Only 5/109 women (4.6%) carried a PV/LPV versus 18/85 men (21.2%) on these genes. FBC did not carry any PV/LPV on 11 of these genes. Although 5.9% of the MBC cohort carried PVs/LPVs in PALLD and ERCC2, neither of these genes were altered in our FBC cohort. Our data suggest that in addition to BRCA1/BRCA2/PALB2, other genes involved in DNA repair/maintenance or genomic stability as well as cell adhesion may form a specific MBC PV/LPV signature.

Non-retroareolar male mucinous breast cancer without gynecomastia development in an elderly man: A case report

BACKGROUND

Male breast cancer (MBC) is an extremely rare condition and accounts for less than 1% of all breast cancers, and malignant tumors occur in less than 1% of the affected men. Mucinous breast cancer is extremely rare and accounts for 2% of all invasive breast cancers. Generally, MBC is accompanied by a retroareolar mass.

CASE SUMMARY

Herein, we report a case of male mucinous breast carcinoma (MMBC) without gynecomastia development and with mass localization outside the common retroareolar region, wherein the mass was a painless nodule in the right breast of a 64-year-old man. We also discuss the clinical and pathological characteristics of this unusual tumor. The excised breast specimen showed pure mucinous carcinoma. The patient had strong expression of estrogen and progesterone receptors, a low Ki-67 proliferation index of the tumor cells, and negative pathological axillary lymph nodes. The patient underwent modified radical mastectomy and axillary lymph node dissection, followed by tamoxifen hormone therapy.

CONCLUSION

To the best of our knowledge, this is the first case report of MMBC in the non-retroareolar region of the nipple without gynecomastia development. Mucinous tumors are easily missed during diagnosis, and the incidence of axillary lymph node metastases of chest mucinous tumors has increased.

Male breast cancer: Report of two cases with bloody nipple discharge

We report 2 rare cases of male breast cancer with bloody nipple discharge. Patient 1, a 32-year-old male, presented with a bloody nipple discharge from the left breast. Diagnostic workup revealed papillary ductal carcinoma in situ. Patient 1 underwent bilateral mastectomy with left axillary sentinel lymph node biopsy and has been doing well ever since. Patient 2, a 70-year-old male with concomitant metastatic prostate cancer, presented with a palpable right breast mass and with initially serous, then bloody nipple discharge. Diagnostic workup revealed invasive ductal carcinoma with ductal carcinoma in situ of the right breast. Patient 2 received aromatase inhibitor therapy prior to right total mastectomy with SLN biopsy followed by adjuvant tamoxifen therapy. Patient 2 recovered without complication for 2 years until metastatic disease recurrence was detected. This case report's purpose is to increase awareness and enhance understanding of the presentation, diagnosis, treatment, and outcomes of rare malignant pathologies.

Axillary Lymph Node Dissection is Associated with Improved Survival Among Men with Invasive Breast Cancer and Sentinel Node Metastasis

BACKGROUND

Male breast cancer (MBC) is rare, and management is extrapolated from trials that enroll only women. It is unclear whether contemporary axillary management based on data from landmark trials in women may also apply to men with breast cancer. This study aimed to compare survival in men with positive sentinel lymph nodes after sentinel lymph node biopsy (SLNB) alone versus complete axillary dissection (ALND).

PATIENTS AND METHODS

Using the National Cancer Database, men with clinically node-negative, T1 and T2 breast cancer and 1-2 positive sentinel nodes who underwent SLNB or ALND were identified from 2010 to 2020. Both 1:1 propensity score matching and multivariate regression were used to identify patient and disease variables associated with ALND versus SLNB. Survival between ALND and SLNB were compared using Kaplan-Meier methods.

RESULTS

A total of 1203 patients were identified: 61.1% underwent SLNB alone and 38.9% underwent ALND. Treatment in academic centers (36.1 vs. 27.7%; p < 0.0001), 2 positive lymph nodes on SLNB (32.9 vs. 17.3%, p < 0.0001) and receipt or recommendation of chemotherapy (66.5 vs. 52.2%, p < 0.0001) were associated with higher likelihood of ALND. After propensity score matching, ALND was associated with superior survival compared with SLNB (5-year overall survival of 83.8 vs. 76.0%; log-rank p = 0.0104).

DISCUSSION

The results of this study suggest that among patients with early-stage MBC with limited sentinel lymph node metastasis, ALND is associated with superior survival compared with SLNB alone. These findings indicate that it may be inappropriate to extrapolate the results of the ACOSOG Z0011 and EORTC AMAROS trials to MBC.

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.

Trichorhinophalangeal syndrome type 1 (TRPS1) expression in male breast carcinoma

Currently, there is a paucity of highly specific and sensitive markers to identify breast carcinoma in male patients. Immunohistochemical stains commonly used for unmasking primary breast carcinomas include estrogen receptor (ER) and GATA3. However, these markers are commonly expressed in carcinomas originating from other organ systems and can be reduced in breast carcinomas with higher histologic grades. Androgen receptor (AR) may be used to highlight primary male breast cancer, but this marker can also be expressed in other carcinomas. We evaluated TRPS1, a highly sensitive and specific marker for female breast carcinoma, in cases of male breast carcinoma. Through an institutional database search, we identified 72 cases of primary invasive breast carcinoma in male patients. Among ER/progesterone receptor (PR)-positive cancers, 97% showed intermediate or high positivity for both TRPS1 and GATA3. Among HER2-positive cancers, 100% showed intermediate or high positivity for TRPS1 and GATA3. One case of triple-negative breast cancer was collected, showing high positivity for TRPS1 and negativity for GATA3. AR staining was non-specific and heterogeneous: 76% showed high positivity, but the remaining 24% showed low or intermediate positivity. Additionally, among 29 cases of metastatic carcinoma to male breast tissue, 93% were negative for TRPS1, and the remaining 2 cases (7%), which were carcinomas from salivary gland primary tumors, were intermediate positive. TRPS1 is a sensitive and specific marker in the unmasking of male primary invasive breast carcinoma across different subtypes. Additionally, TRPS1 is not expressed in metastatic carcinomas of multiple primaries, with the exception of salivary gland primaries.

De novo metastatic breast cancer in men vs women: a Swedish population-based cohort study

Current evidence on de novo metastatic breast cancer is based on data from women. This Swedish population-based cohort study compared the incidence over time and prognosis of de novo metastatic breast cancer between sexes using data from the Swedish National Quality Register for Breast Cancer. Joinpoint regression analysis was used to compare incidence trends in all stages (104 733 women, 648 men) and multivariate Cox regression analysis to investigate potential sex disparities in de novo metastatic breast cancer prognosis (6005 women, 41 men). For both sexes, increased trends were evident for cancer stages I and II, with a stabilizing trend at the later years for women, while stage III incidence remained stable. An increased trend for de novo metastatic breast cancer in women, and to a lesser extent in men, was observed. No difference in de novo metastatic breast cancer overall survival between sexes was observed (hazard ratio = 1.24; 95% confidence interval = 0.85 to 1.81). The comparable features in terms of incidence and prognosis of de novo metastatic breast cancer between sexes imply similarities, supporting the adoption of common treatment strategies.

The prediction of distant metastasis risk for male breast cancer patients based on an interpretable machine learning model

OBJECTIVES

This research was designed to compare the ability of different machine learning (ML) models and nomogram to predict distant metastasis in male breast cancer (MBC) patients and to interpret the optimal ML model by SHapley Additive exPlanations (SHAP) framework.

METHODS

Four powerful ML models were developed using data from male breast cancer (MBC) patients in the SEER database between 2010 and 2015 and MBC patients from our hospital between 2010 and 2020. The area under curve (AUC) and Brier score were used to assess the capacity of different models. The Delong test was applied to compare the performance of the models. Univariable and multivariable analysis were conducted using logistic regression.

RESULTS

Of 2351 patients were analyzed; 168 (7.1%) had distant metastasis (M1); 117 (5.0%) had bone metastasis, and 71 (3.0%) had lung metastasis. The median age at diagnosis is 68.0 years old. Most patients did not receive radiotherapy (1723, 73.3%) or chemotherapy (1447, 61.5%). The XGB model was the best ML model for predicting M1 in MBC patients. It showed the largest AUC value in the tenfold cross validation (AUC:0.884; SD:0.02), training (AUC:0.907; 95% CI: 0.899-0.917), testing (AUC:0.827; 95% CI: 0.802-0.857) and external validation (AUC:0.754; 95% CI: 0.739-0.771) sets. It also showed powerful ability in the prediction of bone metastasis (AUC: 0.880, 95% CI: 0.856-0.903 in the training set; AUC: 0.823, 95% CI:0.790-0.848 in the test set; AUC: 0.747, 95% CI: 0.727-0.764 in the external validation set) and lung metastasis (AUC: 0.906, 95% CI: 0.877-0.928 in training set; AUC: 0.859, 95% CI: 0.816-0.891 in the test set; AUC: 0.756, 95% CI: 0.732-0.777 in the external validation set). The AUC value of the XGB model was larger than that of nomogram in the training (0.907 vs 0.802) and external validation (0.754 vs 0.706) sets.

CONCLUSIONS

The XGB model is a better predictor of distant metastasis among MBC patients than other ML models and nomogram; furthermore, the XGB model is a powerful model for predicting bone and lung metastasis. Combining with SHAP values, it could help doctors intuitively understand the impact of each variable on outcome.

Breast Cancer Screening in Men

Breast cancer screening has been highly successful in women in reducing mortality through early detection. In comparison, clinical detection of breast cancer remains the norm in men, and delay in diagnosis is reflected by a persistent survival disparity compared to women despite advances in modern therapy. Male breast cancer presents an interesting dilemma. While mammography is highly sensitive and specific for male breast cancer, routine screening is not justified by the overall low disease incidence. Yet there has been interest in leveraging mammography in targeted screening of men with identifiable risk factors to allow early detection, and early data may support this approach. The purpose of this article is to explore the potential utility of targeted breast cancer screening in men by examining unique clinical and biologic characteristics of male breast cancers that may lend themselves to mammographic detection. We will also discuss available evidence in screening outcomes in men and summarize recent updates in risk management recommendations in Society guidelines.

Prevalence of Imaging Detected Silent Male Breast Cancer in Autopsy Specimens: Study of the Disease Held by Image-Guided Biopsies

Introduction

Regarding male breast cancer, a rare disease comprising ∼1% of breast cancers, data are generally scant. The present study aimed to quantify the imaging detected breast cancer in male gender corpses, determining in this way the prevalence of silent breast cancer in male gender.

Methodology

The population target has been male corpses without clinical expression of breast cancer. Seventy-four male corpses have been submitted to bilateral subcutaneous radical mastectomy. Samples have been submitted to echography and mammography imaging and every lesion superior to BI-RADS 4a has been excised.

Results

One excisional biopsy has been performed and no case of breast cancer has been identified.

Discussion

Our findings suggest that screening of the general population for male breast cancer is not necessary.

A Rare Case of Invasive Cribriform Carcinoma in Male Breast

BACKGROUND Male breast cancer is a very rare disease that represents 0.6% of all breast carcinomas. Among breast carcinomas, invasive cribriform carcinoma (ICC) is a rare type of breast carcinoma and is more common in older women, with only a few cases in men reported. We present a case of male breast cancer with ICC. CASE REPORT A 58-year-old man presented with a painful and palpable mass in the left breast, which was diagnosed as breast cancer of the ICC type. The patient underwent total mastectomy plus sentinel lymph node biopsy. On the microscope, the tumor was composed of more than 90% cribriform glands with comedo necrosis and dystrophic calcification. On immunohistochemical (IHC) staining, it appeared to be a luminal breast cancer. The IHC staining for c-erb B2 was equivocal (2 positive); hence fluorescence in situ hybridization was performed, and showed no amplification of the HER2/neu oncogene. The Ki-67 labeling index was 30%. The patient received radiotherapy and adjuvant systemic chemotherapy (4 cycles of docetaxel and cyclophosphamide), and has been on antiestrogen therapy (daily tamoxifen, 20 mg) for 30 months with no evidence of disease. CONCLUSIONS ICC is a rare type of invasive carcinoma of the breast, and ICC from the male breast is extremely rare. We report, in this case, the final pathologic results of a male patient diagnosed with ICC breast cancer and treated with surgery, chemotherapy, and radiotherapy.

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.

Tumor Microenvironment in Male Breast Carcinoma with Emphasis on Tumor Infiltrating Lymphocytes and PD-L1 Expression

Male breast cancer (MBC) is rare and usually presents as a locally advanced disease. Stromal tumor-infiltrating lymphocytes (sTILs) are associated with a better response to neoadjuvant chemotherapy and improved prognosis in all molecular subtypes of female breast cancer, but their role in MBC is less clear. We studied sTILs and the expression of programmed cell death ligand 1 (PD-L1) and pan-TRK in MBC. We retrospectively studied 113 cases of MBC surgically treated between 1988 and 2015. The tumors were evaluated for histological type and grade, stage, intrinsic subtype and sTILs. We performed immunohistochemistry for PD-L1 (clone SP142) and pan-TRK (clone EPR17341) on tissue microarrays. Pan-TRK positive cases were further analyzed by next-generation sequencing. The median age was 69 years (range 60−77). Invasive carcinoma of no special type was found in 94.7% of cases, of which 53.1% were grade 2. Estrogen receptor was positive in 92% of the tumors, progesterone receptor in 85.8%, androgen receptor in 70.8%; 4.4% were human epidermal growth factor receptor 2 (HER2)-positive, and 55.8% HER2-low. 40.7% of tumors were luminal A and 51.3% luminal B, 4.4% HER2-enriched and 3.5% triple negative carcinoma. sTILs density was <50% in 96.4% of the tumors, >50% in 3.6% of the tumors. PD-L1 immune cell score >1% was found in 7.1% of the tumors (all of luminal subtype). A weak focal cytoplasmic pan-TRK staining was present in 8.8% but without NTRK fusion. Neither sTILs nor PD-L1 had statistically significant outcomes. Our findings suggest that a subset of MBC patients harbors an immunological environment characterized by increased sTILs with PD-L1 expression. These patients may potentially benefit from immune checkpoint inhibitor therapy. Frequent HER2-low may offer novel anti-HER2 treatment options.

Clinicopathological features, genetic alterations, and BRCA1 promoter methylation in Japanese male patients with breast cancer

PURPOSE

Male breast cancer (MBC) is a rare cancer accounting for only 1% of all male cancers and is, therefore, poorly studied. We aimed to characterize the subtypes of MBC in Japanese patients based on genetic profiling, the presence of tumor-infiltrating cells, and the expression of immunohistochemical markers.

METHODS

This retrospective study included 103 patients with MBC diagnosed between January 2009 and December 2019 at various hospitals in Japan. Clinicopathological patient characteristics were obtained from medical records, and formalin-fixed paraffin-embedded tissue specimens were analyzed for histological markers, mutations of 126 genes, BRCA1 methylation, and stromal tumor-infiltrating lymphocytes.

RESULTS

The median patient age was 71 (range 31-92) years. T1-stage tumors were the most frequent (47.6%), and most were node negative (77.7%). The majority of tumors were positive for estrogen receptor (98.1%), progesterone receptor (95.1%), and androgen receptor (96.1%), and BRCA2 was the most frequently mutated gene (12.6%). The most common treatment was surgery (99.0%), either total mastectomy (91.1%) or partial mastectomy (7.0%). Survival analysis showed a 5-year recurrence-free survival rate of 64.4% (95% confidence interval [CI] 46.7-88.8) and a 5-year overall survival rate of 54.3% (95% CI 24.1-100.0).

CONCLUSION

Japanese MBC is characterized by a high rate of hormonal receptor positivity and BRCA2 somatic mutation. Due to the observed clinicopathological differences in MBC between the Western countries and Japan, further prospective studies are needed to evaluate the most suitable treatment strategies.