African American patients with breast cancer have worse prognosis than white patients in certain subtypes and stages

Racial Differences in Breast Cancer Survival Between Black and White Women According to Tumor Subtype: A Systematic Review and Meta-Analysis

PURPOSE

Despite effective early-detection approaches and innovative treatments, Black women in the United States have higher breast cancer mortality rates compared with White women. The purpose of this systematic review and meta-analysis is to determine the extent of disparities in breast cancer survival between Black and White women according to tumor subtype.

METHODS

A comprehensive database search was performed for full-text, English-language articles published from January 1, 2000, to December 31, 2022. Included studies compared survival between Black and White female patients with breast cancer within subtypes defined by hormone receptor and human epidermal growth factor receptor 2 (HER2)/neu (HER2; now known as ERBB2) status. Random-effects models were used to combine study-specific results and generate pooled relative risks (RRs) and 95% CIs for breast cancer-specific or overall survival (OS). A protocol for this review was registered in PROSPERO (CRD42021268212).

RESULTS

Eighteen studies including 228,885 (34,262 Black; 182,466 White) patients with breast cancer were identified. Compared with White women, Black women had a higher risk of breast cancer death for all tumor subtypes. The summary risk of breast cancer death was 50% higher among hormone receptor-positive HER2-negative [HER2-] tumors (RR, 1.50 [95% CI, 1.30 to 1.72]), 34% higher for hormone receptor+/HER2+ (RR, 1.34 [95% CI, 1.10 to 1.64]), 20% higher for hormone receptor-negative (-)/HER2+ (RR, 1.29 [95% CI, 1.00 to 1.43]), and 17% higher among individuals with hormone receptor-/HER2- tumors (hazard ratio, 1.17; 95% CI, 1.10 to 1.25). Black women also had poorer OS than White women for all subtypes.

CONCLUSION

These results suggest there are both subtype-specific and subtype-independent mechanisms that contribute to disparities in breast cancer survival between Black and White women, which require multilevel interventions to address and achieve health equity.

Higher 10-Year Survival with Breast-Conserving Therapy over Mastectomy for Women with Early-Stage (I-II) Breast Cancer: Analysis of the CDC Patterns of Care Data Base

Background

Studies in the United States are scarce that assess the survival differences between breast-conserving surgery plus radiation (Breast-Conserving Therapy; BCT) and mastectomy groups using population-based data while accounting for sociodemographic and clinical factors that affect the survival of women with early-stage breast cancer (ESBC).

Objective

To assess whether BCT provides superior long-term overall survival (OS) and breast cancer-specific survival (BCSS) compared with mastectomy in women with ESBC, while considering key factors that impact survival.

Design

Cohort study.

Methods

We analyzed data on women aged 20 years and older diagnosed with stage I-II breast cancer (BC) in 2004 who received either BCT or mastectomy. The data were collected by 5 state cancer registries through the Centers for Disease Control and Prevention-funded Patterns of Care study. Multivariable Cox proportional hazard models, accounting for sociodemographic and clinical factors, were used to calculate hazard ratios (HRs) with 95% confidence intervals (CI). Sensitivity analysis involved optimal caliper propensity score (PS) matching to address residual confounding.

Results

Of the 3495 women, 41.5% underwent mastectomy. The 10-year OS and BCSS were 82.7% and 91.1% for BCT and 72.3% and 85.7% for mastectomy, respectively. Adjusted models showed that mastectomy recipients had a 22% higher risk of all-cause deaths (ACD) (HR = 1.22, 95% CI = [1.06, 1.41]) and a 26% higher risk of breast cancer-specific deaths (BCD) (HR = 1.26, 95% CI = [1.02, 1.55]) than BCT recipients. Sensitivity analysis demonstrated that mastectomy was associated with a higher risk of ACD (P < .05) but did not exhibit a statistically significant risk for BCD. Women with HR+/HER2+ (luminal B) or invasive ductal carcinoma BC who underwent mastectomy had higher risks of ACD and BCD compared with BCT recipients, while the hazards for ACD in triple-negative BC did not remain significant after adjusting for covariates.

Conclusion

ESBC BCT recipients demonstrate superior OS and BCSS compared with mastectomy recipients.

High tumor infiltrating lymphocytes are significantly associated with pathological complete response in triple negative breast cancer treated with neoadjuvant KEYNOTE-522 chemoimmunotherapy

INTRODUCTION

For patients with locally advanced triple negative breast cancer (TNBC), the standard of care is to administer the KEYNOTE-522 (K522) regimen, including chemotherapy and immunotherapy (pembrolizumab) given in the neoadjuvant setting. Pathological complete response (pCR) is more likely in patients who receive the K522 regimen than in patients who receive standard chemotherapy. Studies have shown that pCR is a strong predictor of long-term disease-free survival. However, factors predicting pCR to K522 are not well understood and require further study in real-world populations.

METHODS

We evaluated 76 patients who were treated with the K522 regimen at our institution. Twenty-nine pre-treatment biopsy slides were available for pathology review. Nuclear grade, Nottingham histologic grade, Ki-67, lymphovascular invasion, and tumor infiltrating lymphocytes (TIL) were evaluated in these 29 cases. For the cases that did not have available slides for review from pre-treatment biopsies, these variables were retrieved from available pathology reports. In addition, clinical staging, race, and BMI at the time of biopsy were retrieved from all 76 patients' charts. Binary logistic regression models were used to correlate these variables with pCR.

RESULTS

At the current time, 64 of 76 patients have undergone surgery at our institution following completion of K522 and 31 (48.4%) of these achieved pCR. In univariate analysis, only TIL was significantly associated with pCR (p = 0.014) and this finding was also confirmed in multivariate analysis, whereas other variables including age, race, nuclear grade, Nottingham grade, Ki-67, lymphovascular invasion, BMI, pre-treatment tumor size, and lymph node status were not associated with pCR (p > 0.1).

CONCLUSION

Our real-world data demonstrates high TIL is significantly associated with pCR rate in the K522 regimen and may potentially serve as a biomarker to select optimal treatment. The pCR rate of 48.4% in our study is lower than that reported in K522, potentially due to the smaller size of our study; however, this may also indicate differences between real-world data and clinical trial results. Larger studies are warranted to further investigate the role of immune cells in TNBC response to K522 and other treatment regimens.

Lower breast cancer survival among Black women in Brazil: a population-based retrospective study

OBJECTIVES

To analyze the rates of breast cancer survival among Black and White women according to age and stage at diagnosis.

STUDY DESIGN

A retrospective cohort study.

METHODS

The study examined women registered in the population-based cancer registry of Campinas in 2010-2014. The primary variable was the declared race (White or Black). Other races were excluded. Data were linked with the Mortality Information System, and missing information was accessed by active search. Overall survival (OS) was calculated by the Kaplan-Meier method, comparisons were done by chi-squared tests, and hazard ratios were examined by Cox regression.

RESULTS

The total numbers of new cases of staged breast cancer among Black and White women were 218 and 1522 cases, respectively. The rates of stages III/IV were 35.5% among White women and 43.1% among Black women (P = 0.024). The frequencies among White and Black women under 40 years old were 8.0% and 12.4% (P = 0.031), 19.6% and 26.6% (P = 0.016) for ages of 40-49 years, and 23.8% and 17.4% (P = 0.037) for ages of 60-69 years, respectively. The mean OS was 7.5 years (7.0; 8.0) among Black women and 8.4 years (8.2; 8.5) among White women. The 5-year OS was 72.3% among Black women and 80.5% among White women (P = 0.001). Black women had an age-adjusted risk of death that was 1.7 times higher (1.33; 2.20). The risk was 6.4 times higher for diagnoses in stage 0 (1.65; 24.90) and 1.5 times for diagnoses in stage IV (1.04; 2.17).

CONCLUSION

The 5-year OS for women with breast cancer was significantly lower among Black women than White women. Black women were more frequently diagnosed in stages III/IV, and their age-adjusted risk of death was 1.7 times higher. Differences in access to care may explain these differences.

The Landmark Series-Addressing Disparities in Breast Cancer Screening: New Recommendations for Black Women

Randomized, clinical trials have established the efficacy of screening mammography in improving survival from breast cancer for women through detection of early, asymptomatic disease. However, disparities in survival rates between black women and women from other racial and ethnic groups following breast cancer diagnosis persist. Various professional groups have different, somewhat conflicting, guidelines with regards to recommended age for commencing screening as well as recommended frequency of screening exams, but the trials upon which these recommendations are based were not specifically designed to examine benefit among black women. Furthermore, these recommendations do not appear to incorporate the unique epidemiological circumstances of breast cancer among black women, including higher rates of diagnosis before age 40 years and greater likelihood of advanced stage at diagnosis, into their formulation. In this review, we examined the epidemiologic and socioeconomic factors that are associated with breast cancer among black women and assess the implications of these factors for screening in this population. Specifically, we recommend that by no later than age 25 years, all black women should undergo baseline assessment for future risk of breast cancer utilizing a model that incorporates race (e.g., Breast Cancer Risk Assessment Tool [BCRAT], formerly the Gail model) and that this assessment should be conducted by a breast specialist or a healthcare provider (e.g., primary care physician or gynecologist) who is trained to assess breast cancer risk and is aware of the increased risks of early (i.e., premenopausal) and biologically aggressive (e.g., late-stage, triple-negative) breast cancer among black women.

Are there differences in outcomes by race among women with metastatic triple-negative breast cancer?

PURPOSE

Black women have higher breast cancer mortality rates than other groups, with Triple-negative breast cancer (TNBC) being more common among AAs with a worse prognosis. Our study seeks to explore differences among Non-Hispanic Black (NHB) vs. White (NHW) women, with Stage IV TNBC, focusing on survival and treatment patterns.

METHODS

SEER database was queried for TNBC patients diagnosed with metastatic disease from 2012 to 2016. Neighborhood socioeconomic status (nSES) was defined using the Yost index based on income, education, housing, and employment. Univariate and multivariate analyses were performed to evaluate receipt of surgery, radiation, and chemotherapy. Overall survival was evaluated using Kaplan-Meier curve and Cox proportional hazards model analysis.

RESULTS

25,761 TNBC cases were identified with 1420 being metastatic (5.5%). Bone was the most common site for metastasis, with patients' age being 63.7 years for NHW vs. 59.5 years for NHB. NHB women had the highest percentage of low nSES (62.3% vs 29.3%; p value = 0.001). On univariate analysis, fewer NHBs received radiation compared to NHWs (27.1 vs. 32.6%; p value = 0.040). On multivariate analysis, all women were less likely to undergo treatment if unmarried (p value < 0.01). NHB women had lower median survival compared to NHW women (13 vs. 15 months; p value < 0.01). Receipt of surgery and chemotherapy reduced the risk of mortality (p value < 0.01).

CONCLUSION

NHB women had lower median survival with metastatic TNBC. Race was associated with different treatment utilization. With a mortality differential between NHW and NHB women with metastatic TNBC, more investigation is needed to inform strategies to reduce this disparity.

A Contemporary Analysis of Racial and Ethnic Disparities in Diagnosis of Early-Stage Breast Cancer and Stage-Specific Survival by Molecular Subtype

BACKGROUND

Prior studies of breast cancer disparities have focused primarily on differences between Black and White women, yet contemporary patterns of disparity for other groups are not well understood. We examine breast cancer disparities by stage at diagnosis across nine racial and ethnic groups.

METHODS

The SEER 18 registries identified 841,975 women diagnosed with breast cancer from 2000 to 2017. Joinpoint models assessed trends in diagnosis stage and survival. Multivariable logistic regression evaluated associations between race/ethnicity and diagnosis stage. Multivariable Cox models compared survival of groups by stage and molecular subtype.

RESULTS

Black, American Indian, Southeast Asian, South Asian, Pacific Islander, and Hispanic women were less likely than white women to be diagnosed with early stage breast cancer. Among those diagnosed at early stage, Hispanic, American Indian, Pacific Islander and Black women were 9%, 14%, 22%, and 39% (respectively) more likely than White women to die from breast cancer, whereas Asian subgroups had lower risk of death. Among those diagnosed at late stage, Black women were 18% more likely than White counterparts to die from breast cancer, and survival disparities for Black women persisted across all subtypes and stages, (except late stage HR-/HER2-). East Asian women with early stage HR+/HER2- tumors had better survival than White women.

CONCLUSIONS

Persistent disparities in early detection and survival of breast cancer demand further work to address and reduce disparities across the cancer continuum.

IMPACT

Results have implications for efforts to reduce entrenched racial and ethnic disparities in breast cancer early detection and survival.

Personalized Nutrition as a Key Contributor to Improving Radiation Response in Breast Cancer

Understanding metabolic and immune regulation inherent to patient populations is key to improving the radiation response for our patients. To date, radiation therapy regimens are prescribed based on tumor type and stage. Patient populations who are noted to have a poor response to radiation such as those of African American descent, those who have obesity or metabolic syndrome, or senior adult oncology patients, should be considered for concurrent therapies with radiation that will improve response. Here, we explore these populations of breast cancer patients, who frequently display radiation resistance and increased mortality rates, and identify the molecular underpinnings that are, in part, responsible for the radiation response and that result in an immune-suppressive tumor microenvironment. The resulting immune phenotype is discussed to understand how antitumor immunity could be improved. Correcting nutrient deficiencies observed in these populations should be considered as a means to improve the therapeutic index of radiation therapy.

Racial/ethnic disparities in risk of breast cancer mortality by molecular subtype and stage at diagnosis

PURPOSE

Previous research has found significant survival disparities between Black and White women among select stages and subtypes of breast cancer, however other racial/ethnic groups have been less well-studied. This study expands on previous research, examining differences in breast cancer-specific mortality across multiple racial and ethnic groups.

METHODS

Women diagnosed with a first primary invasive breast cancer between 2010 and 2016 who were 20-85 years of age at diagnosis were identified from 18 Surveillance, Epidemiology, and End Results (SEER) registries. Subtypes were defined by joint hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. Cox proportional hazards models for each stage and subtype were fit, with non-Hispanic white women as the reference group. Effect modification by age at diagnosis (< 50, ≥ 50) was found and thus analyses were age-stratified.

RESULTS

After multivariable adjustment, younger Black women had greater risks of breast cancer-specific death for all stages of HR+/HER2-, and certain stages of HR+/HER2+ , TN, and HR-/HER2 + breast cancer. Asian/Pacific Islander women generally had a lower hazard of breast cancer-specific death. Older Hispanic White women had a lower hazard of breast cancer-specific death for stages I-III HR + /HER2- and stage II TN breast cancer.

CONCLUSIONS

These findings demonstrate that different racial/ethnic groups experience different risks of breast cancer-specific mortality by stage and subtype. Efforts to address survival disparities should place additional focus on young Black women, as they experience meaningful disparities in breast cancer-specific mortality.

Prognostic Factors in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative (HR+/HER2-) Advanced Breast Cancer: A Systematic Literature Review

PURPOSE

Advanced breast cancer is a heterogeneous disease with several well-defined subtypes, among which, hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) is most prevalent. Determination of HR and HER2 status influences prognosis and, thus, disease management. Although literature on these prognostic factors exist, especially in the early breast cancer setting, it remains unclear to what extent these factors can guide clinical decision-making in the advanced disease setting. Therefore, we sought to identify the strength and consistency of evidence for prognostic factors in patients with HR+/HER2- advanced breast cancer.

METHODS

A systematic literature review (SLR) of the major electronic databases was conducted in November 2018 for primary research studies published since 2010. Endpoints of interest were tumor response, progression-free survival (PFS), overall survival (OS), and breast cancer-specific survival (BCSS).

RESULTS

Seventy-nine studies were included wherein all patients were diagnosed with advanced breast cancer and ≥50% of the population were HR+/HER2-. OS was the most commonly assessed endpoint (n=67) followed by PFS (n=33), BCSS (n=5) and tumor response (n=3). The prognostic factors with strongest evidence of association with worse OS were negative progesterone receptor status, higher tumor grade, higher circulating tumor cell (CTC) count and higher Ki67 level, number of metastatic sites (eg multiple vs single) and sites of metastases (eg presence of liver metastases vs absence), shorter time to recurrence or progression to advanced breast cancer, poor performance status, prior therapy attributes in the early or metastatic setting (type of therapy, treatment line, response of prior therapy), and race (black vs white). The prognostic factors that had strongest evidence of association with PFS included CTC count, number and sites of metastases, and absence of prior therapy or higher lines of therapy in the early or metastatic setting. The directionality of association was consistent for all prognostic factors except between lymph node and OS, and de novo metastatic breast cancer and PFS.

CONCLUSION

Multiple disease, treatment, and patient-related prognostic factors impact survival, particularly OS, in patients with HR+/HER2- advanced breast cancer. Treatment outcomes can vary considerably due to these factors. Understanding poorer prognostic factors for patients can result in improved clinical decision-making.

Race May Not Impact Endocrine Therapy-Related Changes in Breast Density

BACKGROUND

Reduction in breast density may be a biomarker of endocrine therapy (ET) efficacy. Our objective was to assess the impact of race on ET-related changes in volumetric breast density (VBD).

METHODS

This retrospective cohort study assessed longitudinal changes in VBD measures in women with estrogen receptor-positive invasive breast cancer treated with ET. VBD, the ratio of fibroglandular volume (FGV) to breast volume (BV), was measured using Volpara software. Changes in measurements were evaluated using a multivariable linear mixed effects model.

RESULTS

Compared with white women (n = 191), black women (n = 107) had higher rates of obesity [mean ± SD body mass index (BMI) 34.5 ± 9.1 kg/m² vs. 30.6 ± 7.0 kg/m², P < 0.001] and premenopausal status (32.7% vs. 16.7%, P = 0.002). Age- and BMI-adjusted baseline FGV, BV, and VBD were similar between groups. Modeled longitudinal changes were also similar: During a follow-up of 30.7 ± 15.0 months (mean ± SD), FGV decreased over time in premenopausal women (slope = -0.323 cm³; SE = 0.093; P = 0.001), BV increased overall (slope = 2.475 cm³; SE = 0.483; P < 0.0001), and VBD decreased (premenopausal slope = -0.063%, SE = 0.011; postmenopausal slope = -0.016%, SE = 0.004; P < 0.0001). Race was not significantly associated with these longitudinal changes, nor did race modify the effect of time on these changes. Higher BMI was associated with lower baseline VBD (P < 0.0001). Among premenopausal women, VBD declined more steeply for women with lower BMI (time × BMI, P = 0.0098).

CONCLUSIONS

Race does not appear to impact ET-related longitudinal changes in VBD.

IMPACT

Racial disparities in estrogen receptor-positive breast cancer recurrence and mortality may not be explained by differential declines in breast density due to ET.

Clinicopathologic Factors Associated With Response to Neoadjuvant Anti-HER2-Directed Chemotherapy in HER2-Positive Breast Cancer

BACKGROUND

HER2-targeted neoadjuvant therapy has high efficacy in treating HER2-positive breast cancer. Response to neoadjuvant therapy helps clinicians make treatment decisions and make estimates about prognosis. This study examined clinicopathologic features to determine which may be most predictive of response to neoadjuvant therapy in HER2⁺ breast cancer.

PATIENTS AND METHODS

Patients with HER2⁺ breast cancer (n = 173) who had an initial biopsy performed between 2010 and 2016 were identified at our institution. Tumor response was evaluated on excisional specimens using the MD Anderson residual cancer burden (RCB) classification. Tumors with pathologic complete response (defined as no residual invasive carcinoma in the breast and lymph nodes) and RCB-I were classified as having response and tumors with RCB-II and -III as having no response. Patient age, tumor size, nuclear grade (1/2 vs. 3), mitosis, Nottingham grade, HER2 immunohistochemistry (1/2+ vs. 3+), HER2/CEP17 (chromosome enumeration probe 17) ratio, HER2 copy number, estrogen receptor, progesterone receptor, Ki-67, and tumor-infiltrating lymphocytes (TIL) were evaluated and correlated with response. TILs were evaluated for an average and also for the hot spot/total tumor stromal ratio.

RESULTS

Small tumor size, low estrogen receptor and progesterone receptor expression, HER2 immunohistochemistry 3+, high Ki-67, high HER2/CEP17 ratio, and high HER2 copy number were significantly associated with response (all P < .05). TIL hot spot was associated with RCB in univariate (P < .05) but not multivariate analyses.

CONCLUSION

Clinicopathologic features may help predict HER2⁺ breast cancer response to neoadjuvant therapy. Larger studies would be useful to confirm these associations, which may have relevance to clinical practice.

Racial/ethnic differences in the outcomes of patients with metastatic breast cancer: contributions of demographic, socioeconomic, tumor and metastatic characteristics

PURPOSE

Population-based estimates of racial disparities in metastatic breast cancer are lacking. We quantified the contributions of demographic, socioeconomic, tumor, and metastatic characteristics to racial differences in metastatic breast cancer and characterized the most disproportional subgroup.

METHODS

Patients diagnosed with metastatic breast cancer between 2010 and 2014 were identified using the Surveillance, Epidemiology, and End Results database. A multivariable Cox proportional hazards model was used to adjust each set of variables. The excess relative risk of cancer-specific and all-cause death in non-Hispanic black (NHB) versus non-Hispanic white women diagnosed with metastatic breast cancer was expressed as a percentage and was stratified by the age at diagnosis.

RESULTS

We identified 13,066 female patients. NHB women exhibited substantially higher morbidity and mortality than women of other races/ethnicities. The greatest excess mortality risk for NHB women was observed in the young-onset group (18-49 years; hazard ratio: 1.57), followed by the middle-age group (50-64 years; hazard ratio: 1.42); the trend was not significant among the elderly group. Socioeconomic factors stably explained one-half of the excess risk, whereas the contribution of tumor characteristics obviously decreased with age (18-49 years, 40.7%; 50-64 years, 33.9%), and the metastatic pattern accounted for approximately one-tenth of the excess risk. Additionally, the disproportional death burden of NHB women persisted in less aggressive subgroups.

CONCLUSIONS

By providing a comprehensive assessment of racial differences in the incidence and outcomes of patients with metastatic breast cancer, we urge the implementation of targeted preventive efforts in both the public health and clinical arenas.

Application of prophylactic cranial irradiation in limited-stage small-cell lung cancer: which patients could benefit?

Aim: To analyze the role of prophylactic cranial irradiation (PCI) on the survival for patients with limited-stage small-cell lung cancer (LS-SCLC). Patients & methods: We screened patients from SEER database. Kaplan–Meier analysis and Cox proportional hazard model were used to evaluate factors influencing survival. Results: LS-SCLC patients who receiving PCI were associated with better overall survival (OS; p < 0.001) and cancer-specific survival (CSS; p < 0.001). Multivariable Cox analysis revealed PCI was an independent prognostic factor for OS (p < 0.001) and CSS (p < 0.001). In subgroup analysis, there were no OS and CSS differences between PCI and no PCI groups in black patients and patient with a tumor size <5 cm (all p > 0.05). Conclusion: PCI remains an effective method for most LS-SCLC patients. However, caution should be taken in recommending PCI for black patients and patients with a tumor size <5 cm. Further clinical trials are necessary to validate our results and identify the most suitable patients for PCI in the modern era.

Validation of the newly proposed American Joint Committee on Cancer (AJCC) breast cancer prognostic staging group and proposing a new staging system using the National Cancer Database

BACKGROUND

The eighth edition of AJCC cancer staging manual incorporated biomarker status into the prognostic staging group (PSG). We used data from National Cancer Database (NCDB) to validate and improve the PSG.

METHODS

All patients had surgery and at least some systemic treatment (endocrine therapy, chemotherapy or HER2 targeted therapy). Information from 420,520 patients was assessed for potential predictors of overall survival (OS), including age at diagnosis (age), tumor grade (G), hormonal receptor and HER2 status, and presence of lymph vascular invasion (LVI), stratified by stage or sub-stages. Based on the multivariate Cox analyses, we built different point systems to predict OS and evaluated the different point systems by Akaike's information criterion (AIC), Harrell's concordance index (C-index), and Uno's concordance index.

RESULTS

Age, G, hormonal receptor and HER2 status, LVI and being TNBC were significantly associated with OS (all P < 0.0001). Three staging systems were correlated with OS: system 1 was the conventional anatomic TNM staging; system 2 included TNM, age, G, hormonal receptor, HER2, and LVI; system 3 included TNM, age, G, TNBC versus non-TNBC, and LVI. System 3 (C-index; 0.7316; AIC: 488138.91) achieved the best balance between predictive performance and goodness-of-fit to the NCDB data as compared to system 2 (C-index: 0.7325; AIC: 498087.73) and system 1 (C-index: 0.716; AIC: 688536.49).

CONCLUSIONS

The new PSG is a better staging system than the conventional anatomic TNM system. Grouping breast cancer into TNBC versus non-TNBC may be simpler while retaining similar accuracy as using ER/PR/HER2 status to predict OS.