The prevalence of estrogen receptor-negative breast cancer in Ethiopia

PAM50 breast cancer subtypes and survival of patients in rural Ethiopia without adjuvant treatment: a prospective observational study

PURPOSE

Survival rates of breast cancer (BC) patients are particularly low in rural regions in sub-Saharan Africa (SSA) which is due to limited access to therapy. In recent years, gene expression profiling (GEP) of BC showed a strong prognostic value in patients with local tumour surgery and (neo)adjuvant treatment. The aim of this study was to evaluate the impact of intrinsic subtypes on survival of patients in rural Ethiopia without any (neo)adjuvant therapy.

METHODS

In total, 113 female patients from Aira Hospital with histologically proven BC and treated only with surgery were included in this study. All samples were analysed by immunohistochemistry (IHC) for estrogen receptor, progesterone receptor, HER2 and Ki67, as well as RNA-expression analysis for PAM50 subtyping.

RESULTS

A positive hormone receptor status was found in 69.0% of the tumours and intrinsic subtyping demonstrated Luminal B to be the most common subtype (34.5%). Follow-up data was available for 79 of 113 patients. Two-year overall survival (OS) was 57.3% and a considerably worse OS was observed in patients with Basal-like BC compared to Luminal A BC. Moreover, advanced tumours showed an increased risk of mortality.

CONCLUSION

The OS was very low in the patient cohort that received no (neo)adjuvant treatment. Immunohistochemistry and GEP confirmed endocrine-sensitive tumours in more than half of the patients, with a large proportion of Luminal B, HER2-enriched and Basal-like tumours so that adjuvant chemotherapy should be recommended.

Proportion of early-stage breast cancer at diagnosis in Ethiopia: a systematic review and meta-analysis

BACKGROUND

Breast cancer is the most common cancer-affecting women globally, with disproportionally high mortality rates in lower-income countries, including Ethiopia. The stage at diagnosis is a well-defined predictive system that determines the likelihood of breast cancer mortality. Early-stage breast cancer at diagnosis is associated with better treatment outcomes as compared with late stage. Although there are numerous primary studies on women with breast cancer with different proportions of early-stage breast cancer, there is currently no summary data on what proportion of breast cancer was diagnosed at early-stage in Ethiopia. This study focused on a pooled proportion of early-stage breast cancer at diagnosis in Ethiopia.

METHODS

By using key terms, Medline through Pub-Med, Google Scholar, Science Direct, HINARI and Medley were searched about breast cancer in Ethiopia, and a total of 288 articles were retrieved. After screening the articles and quality of each article was assessed using Newcastle-Ottawa Scale. Finally, 41 articles were used for the final pooled proportion. A random effects model was used to estimate the pooled prevalence and heterogeneity of included studies that were then assessed by using prediction interval.

RESULTS

Pooled proportion of early-stage breast cancer at diagnosis in Ethiopian hospitals was found to be 36% with a 95% confidence interval ranging from 31 to 41% and a 95% prediction interval ranging from 28 to 45%.

CONCLUSION

Most breast cancer patients (64%) in Ethiopia are diagnosed at a late-stage. This contributes to the high mortality rates of breast cancer among women in Ethiopia. Therefore, in line with recommendations by the World Health Organization, we recommend that there should be an emphasis in Ethiopia to focus on early detection of breast cancer.

Late-stage diagnosis: The driving force behind high breast cancer mortality in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Breast cancer continues to be the most common malignancy and the leading cause of cancer-related deaths in Ethiopia. The poor prognosis and high mortality rate of breast cancer patients in the country are largely caused by late-stage diagnosis. Hence, understanding the epidemiology of late-stage diagnosis is essential to address this important problem. However, previous reports in Ethiopia indicated inconsistent findings. Therefore, this literature review was conducted to generate dependable evidence by summarizing the prevalence and determinants of late-stage diagnosis among breast cancer patients in Ethiopia.

METHODS

Pertinent articles were retrieved by systematically searching on major electronic databases and gray literature. Data were extracted into an Excel spreadsheet and analyzed using the STATA 17 statistical software. The pooled estimates were summarized using the random effect meta-analysis model. Heterogeneity and small study effect were evaluated using the I2 statistics and Egger's regression test in conjunction with the funnel plot, respectively. Meta-regression, sub-group analysis, and sensitivity analysis were also employed. Protocol registration number: CRD42024496237.

RESULTS

The pooled prevalence of late-stage diagnosis after combining reports of 24 studies with 8,677 participants was 65.85 (95% CI: 58.38, 73.32). Residence (adjusted OR: 1.92; 95% CI: 1.45, 2.53), patient delay at their first presentation (adjusted OR: 2.65; 95% CI: 1.56, 4.49), traditional medicine use (adjusted OR: 2.54; 95% CI: 1.89, 3.41), and breast self-examination practice (adjusted OR: 0.28; 95% CI: 0.09, 0.88) were significant determinants of late-stage diagnosis.

CONCLUSION

Two-thirds of breast cancer patients in Ethiopia were diagnosed at an advanced stage. Residence, delay in the first presentation, traditional medicine use, and breast self-examination practice were significantly associated with late-stage diagnosis. Public education about breast cancer and its early detection techniques is crucial to reduce mortality and improve the survival of patients. Besides, improving access to cancer screening services is useful to tackle the disease at its curable stages.

Building pathology capacity in sub-Saharan Africa to improve breast cancer diagnosis and treatment: training laboratory technicians in high-quality manual immunohistochemistry

BACKGROUND

To address the need for a skilled workforce in breast cancer (BC) pathology in sub-Saharan Africa (SSA), we implemented an education program to train laboratory technicians in manual immunohistochemistry (IHC).

METHODS

A quality improvement education project was developed. Interactive webinars were held every six months with didactics and presentations from African experts with experience in IHC. We conducted knowledge assessments and surveys on current practice, equipment, and human resources. A digital mentorship platform (DMP) was created for discussions, sharing SOPs, and networking. For one year (2022-2023), we followed developments in pathology capacity, practice changes, and educational needs. A paired t-test was used to calculate the significance of changes in knowledge immediately after the webinar and comfort level with topics 35 days after the webinar.

RESULTS

Two hundred and sixty six participants from 10 SSA countries attended the first webinar, a series of six lectures on IHC theory, methods, and practice. Ninety-five participants from nine SSA countries provided a baseline assessment of pathology capacity and feedback. Mean knowledge increased by 17.4% immediately after the webinar (from 41.8% pre-webinar to 59.2% post, p =  < 0.0001). Self-reported comfort level in topics 35 days after the webinar increased by 11.3%, but this was not statistically significant (mean 3.36 pre- to 3.74 post, p = 0.1). Over six months, recordings were accessed 412 times. After six months, the second webinar had 93 participants from eight SSA countries. Membership in the DMP increased from 64 to 172; recordings were viewed 412 times in six months; and 113 participants from nine SSA countries completed surveys. Among 74 respondents who perform IHC, 43.5% reported moderate or significant positive practice changes such as improved antigen retrieval techniques and optimization of preanalytical variables. Over half (52.7%, n = 39) reported the quality of slides had moderately or significantly improved. After one year, a third webinar had 98 participants from eight SSA countries. Thirty-eight completed surveys, DMP membership increased to 199, and 1 reported launching IHC in a lab in Nigeria.

CONCLUSIONS

Our program 1) reached hundreds of participants and provided a baseline assessment of pathology capacity across nine SSA countries; 2) created a novel mechanism to build pathology capacity and assess progress with this cohort; and 3) improved practices and the preparation of slides for over half performing manual IHC. After one year, interest was sustained. Tracking impact on diagnosis and treatment of BC in the region is needed long-term.

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.

Immunohistochemistry versus PCR Technology for Molecular Subtyping of Breast Cancer: Multicentered Expereinces from Addis Ababa, Ethiopia

The application of immunohistochemistry (IHC) for molecular characterization of breast cancer (BC) is of paramount importance; however, it is not universally standardized, subject to observer variability and quantifying is a challenge. An alternative molecular technology, such as endpoint reverse transcription (RT)-PCR gene expression analysis, may improve observer variability and diagnostic accuracy. This study was intended to compare IHC with the RT-PCR based technique and assess the potential of RT-PCR for molecular subtyping of BC. In this comparative cross-sectional study, 54 BC tissues were collected from three public hospitals in Addis Ababa and shipped to Gynaecology department at Martin-Luther University (Germany) for laboratory analysis. Only 41 samples were qualified for IHC and RT-PCR investigation of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 protein expression analysis. Kappa statistics was used to assess the concordance between the two techniques. The overall percent agreement between RT-PCR and IHC was 68.3% for ER (positive percent agreement [PPA] 71.1%; negative percent agreement [NPA] 33.3%), 39.0% for PR (PPA 14.3%; NPA 92.3%), and 82.9% for HER2 (PPA 62.5%; NPA 87.9%). Cohen's κ-values of 0.018 (< 0.20), 0.045 (< 0.200), and 0.481 (0.41-0.60) were generated for ER, PR, and HER2, respectively. Concordance for molecular subtypes was only 56.1% (23/41) and 0.20 kappa value. IHC and endpoint RT-PCR techniques have shown to be discordant for 43% samples. Molecular subtyping using endpoint RT-PCR was fairly concordant with IHC. Thus, endpoint RT-PCR may give an objective result, and can be applied for BC subtyping.

Pregnancy Associated Invasive Apocrine Carcinoma of the Breast: Case Report from Ethiopia

We present a case report on a case of invasive apocrine carcinoma of breast during pregnancy at a tertiary referral hospital in Ethiopia. The patient's case in this report signifies the challenging clinical situation that the patient, developing fetus and treating physicians have to go through and the need to improve maternal-fetal medicine and oncologic setup and treatment guidelines in Ethiopia. Our case also illustrates the huge disparity between the management of both breast cancer and its occurrence during pregnancy in low-income countries like Ethiopia and developed nations elsewhere. Our case report shows a rare histological finding. The patient has invasive apocrine carcinoma of the breast. To our knowledge, it is the first case to be reported in the country.

Regional Variation in the Tumor Microenvironment, Immune Escape and Prognostic Factors in Breast Cancer in Sub-Saharan Africa

The low overall survival rates of patients with breast cancer in sub-Saharan Africa (SSA) are driven by regionally differing tumor biology, advanced tumor stages at diagnosis, and limited access to therapy. However, it is not known whether regional differences in the composition of the tumor microenvironment (TME) exist and affect patients' prognosis. In this international, multicentre cohort study, 1,237 formalin-fixed, paraffin-embedded breast cancer samples, including samples of the "African Breast Cancer-Disparities in Outcomes (ABC-DO) Study," were analyzed. The immune cell phenotypes, their spatial distribution in the TME, and immune escape mechanisms of breast cancer samples from SSA and Germany (n = 117) were investigated using histomorphology, conventional and multiplex IHC, and RNA expression analysis. The data revealed no regional differences in the number of tumor-infiltrating lymphocytes (TIL) in the 1,237 SSA breast cancer samples, while the distribution of TILs in different breast cancer IHC subtypes showed regional diversity, particularly when compared with German samples. Higher TIL densities were associated with better survival in the SSA cohort (n = 400), but regional differences concerning the predictive value of TILs existed. High numbers of CD163+ macrophages and CD3+CD8+ T cells accompanied by reduced cytotoxicity, altered IL10 and IFNγ levels and downregulation of MHC class I components were predominantly detected in breast cancer samples from Western SSA. Features of nonimmunogenic breast cancer phenotypes were associated with reduced patient survival (n = 131). We therefore conclude that regional diversity in the distribution of breast cancer subtypes, TME composition, and immune escape mechanisms should be considered for therapy decisions in SSA and the design of personalized therapies. See related Spotlight by Bergin et al., p. 705.

Adherence to Chemotherapy among Women with Breast Cancer Treated at Tikur Anbessa Specialized and Teaching Hospital, Addis Ababa, Ethiopia

BACKGROUND

Adherence is important for women with breast cancer because it is a primary determinant for effectiveness of treatment and optimum clinical benefit. Though Breast cancer is the leading cancer in Ethiopia,adherance to chemotherapy is not investigated in Ethiopian women.

OBJECTIVE

This study aimed to assess adherence to chemotherapy among women with breast cancer treated at Tikur Anbessa specialized and Teaching Hospital.

METHODS

Cross-sectional study was conducted among 164 breast cancer patients with chemotherapy. After eligible participants were identified, data were collected using face-to-face interviews, card reviews and telephone interviews. Adherence was calculated as the number of doses taken divided by number of recommended or expected doses. Pearson chi-square test was used to evaluate predictors of adherence.

RESULTS

Among a total of 164 breast cancer patients, majority, 119, (72.6%) of them were urban residents. The mean age of study participants was 41.99 + 10.9 years. The majority 149, (90.9%) of patients were married. More than half 94, (57.3%) of the women were literate. In this study, 137 out of 164 (83.5%) women were adherent to their chemotherapy. Of the 27 non adherent participants. he reason for non-adherence to chemotherapy was unknown for 7, (25.9%) of women. Among different identified reasons for non-adherent, sever illness prevents patients to receive chemotherapy. Based on Pearson chi square test, distance from referral center and treatment regimen were significantly associated with non-adherence rate.

CONCLUSION

The present  study the results showed that the majority 137, (83.5%) of patients were in good adherence to their chemotherapy. The most identified factor of non-adherence was inability to come for their therapy as a result of severity of illness. Therefore, expansion of cancer diagnosis and treatment centers should be encouraged in order to maximize patient's access and adherence to chemotherapy.

Pharmacogenetics of Breast Cancer Treatments: A Sub-Saharan Africa Perspective

Breast cancer is the most frequent cause of cancer death in low- and middle-income countries, in particular among sub-Saharan African women, where response to available anticancer treatment therapy is often limited by the recurrent breast tumours and metastasis, ultimately resulting in decreased overall survival rate. This can also be attributed to African genomes that contain more variation than those from other parts of the world. The purpose of this review is to summarize published evidence on pharmacogenetic and pharmacokinetic aspects related to specific available treatments and the known genetic variabilities associated with metabolism and/or transport of breast cancer drugs, and treatment outcomes when possible. The emphasis is on the African genetic variation and focuses on the genes with the highest strength of evidence, with a close look on CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, CYP19A1, UGT1A4, UGT2B7, UGT2B15, SLC22A16, SLC38A7, FcγR, DPYD, ABCB1, and SULT1A1, which are the genes known to play major roles in the metabolism and/or elimination of the respective anti-breast cancer drugs given to the patients. The genetic variability of their metabolism could be associated with different metabolic phenotypes that may cause reduced patients' adherence because of toxicity or sub-therapeutic doses. Finally, this knowledge enhances possible personalized treatment approaches, with the possibility of improving survival outcomes in patients with breast cancer.

Intrinsic subtypes in Ethiopian breast cancer patient

PURPOSE

The recent development of multi-gene assays for gene expression profiling has contributed significantly to the understanding of the clinically and biologically heterogeneous breast cancer (BC) disease. PAM50 is one of these assays used to stratify BC patients and individualize treatment. The present study was conducted to characterize PAM50-based intrinsic subtypes among Ethiopian BC patients.

PATIENTS AND METHODS

Formalin-fixed paraffin-embedded tissues were collected from 334 BC patients who attended five different Ethiopian health facilities. All samples were assessed using the PAM50 algorithm for intrinsic subtyping.

RESULTS

The tumor samples were classified into PAM50 intrinsic subtypes as follows: 104 samples (31.1%) were luminal A, 91 samples (27.2%) were luminal B, 62 samples (18.6%) were HER2-enriched and 77 samples (23.1%) were basal-like. The intrinsic subtypes were found to be associated with clinical and histopathological parameters such as steroid hormone receptor status, HER2 status, Ki-67 proliferation index and tumor differentiation, but not with age, tumor size or histological type. An immunohistochemistry-based classification of tumors (IHC groups) was found to correlate with intrinsic subtypes.

CONCLUSION

The distribution of the intrinsic subtypes confirms previous immunohistochemistry-based studies from Ethiopia showing potentially endocrine-sensitive tumors in more than half of the patients. Health workers in primary or secondary level health care facilities can be trained to offer endocrine therapy to improve breast cancer care. Additionally, the findings indicate that PAM50-based classification offers a robust method for the molecular classification of tumors in the Ethiopian context.

OUP accepted manuscript

Introduction

Many women in rural Ethiopia do not receive adjuvant therapy following breast cancer surgery despite the majority being diagnosed with estrogen-receptor-positive breast cancer and tamoxifen being available in the country. We aimed to compare a breast nurse intervention to improve adherence to tamoxifen therapy for breast cancer patients.

Methods and Materials

The 8 hospitals were randomized to intervention and control sites. Between February 2018 and December 2019, patients with breast cancer were recruited after their initial surgery. The primary outcome of the study was adherence to tamoxifen therapy by evaluating 12-month medication-refill data with medication possession ratio (MPR) and using a simplified medication adherence scale (SMAQ) in a subjective assessment.

Results

A total of 162 patients were recruited (87 intervention and 75 control). Trained nurses delivered education and provided literacy material, gave additional empathetic counselling, phone call reminders, and monitoring of medication refill at the intervention hospitals. Adherence according to MPR at 12 months was high in both the intervention (90%) and control sites (79.3%) (P = .302). The SMAQ revealed that adherence at intervention sites was 70% compared with 44.8% in the control sites (P = .036) at 12 months. Persistence to therapy was found to be 91.2% in the intervention and 77.8% in the control sites during the one-year period (P = .010).

Conclusion

Breast nurses can improve cost-effective endocrine therapy adherence at peripheral hospitals in low-resource settings. We recommend such task sharing to overcome the shortage of oncologists and distances to central cancer centers.

Adherence to Newly Implemented Tamoxifen Therapy for Breast Cancer Patients in Rural Western Ethiopia

INTRODUCTION

Endocrine therapy for breast cancer (BC) patients is highly underutilized in rural Ethiopia and other African countries.

OBJECTIVE

This study aims to assess the feasibility of and adherence to tamoxifen therapy in rural Ethiopia.

METHODS

We ascertained the hormone receptor (HR) status in 101 women diagnosed with BC from January 2010 to December 2015 and who had surgery in Aira Hospital, in rural Ethiopia. From 2013, tamoxifen was offered to patients with HR-positive (HR+) tumors. Prescription refill records and a structured questionnaire were used to assess receipt of and adherence to tamoxifen.

RESULTS

Of the 101 BC patients tested for HR status during the study period, 66 (65%) patients were HR+ and were eligible for tamoxifen treatment. However, 15 of the HR+ patients died before tamoxifen became available in 2013. Of the remaining 51 HR+ patients, 26 (51%) initiated tamoxifen but only 9 of them (35%) adhered to therapy (medication possession rate ≥80%, median observation 16.2 months). After 1 year, 52% of the patients were still adherent, and 9 patients had discontinued therapy. The reasons for non-initiation of tamoxifen included patient factors (n = 5), including financial hardship or lack of transportation, and health care provider factors (n = 12).

CONCLUSIONS

Endocrine therapy for BC patients seems feasible in rural Western Ethiopia, although non-adherence due to financial hardship and a less developed health care infrastructure remains a major challenge. We postulate that the implementation of breast nurses could reduce patient and health system barriers and improve initiation of and adherence to endocrine treatment.

Genetic Mutations Associated with Hormone-Positive Breast Cancer in a Small Cohort of Ethiopian Women

In Ethiopia, a breast cancer diagnosis is associated with a prognosis significantly worse than that of Europe and the US. Further, patients presenting with breast cancer in Ethiopia are far younger, on average, and patients are typically diagnosed at very late stages, relative to breast cancer patients of European descent. Emerging data suggest that a large proportion of Ethiopian patients have hormone-positive (ER⁺) breast cancer. This is surprising given (1) that patients have late-stage breast cancer at the time of diagnosis, (2) that African Americans with breast cancer frequently have triple negative breast cancer (TNBC), and (3) these patients typically receive chemotherapy, not hormone-targeting drugs. To further examine the similarity of Ethiopian breast tumors to those of African Americans or of those of European descent, we sequenced matched tumor and normal adjacent tissue from Ethiopian patients from a small pilot collection. We identified mutations in 615 genes across all three patients, unique to the tumor tissue. Across this analysis, we found far more mutations shared between Ethiopian patient tissue and that from white patients (103) than we did comparing to African Americans (3). Several mutations were found in extracellular matrix encoding genes with known roles in tumor cell growth and metastasis. We suggest future mechanistic studies on this disease focus on these genes first, toward finding new treatment strategies for breast cancer patients in Ethiopia.

Comparative analysis of triple-negative breast cancer transcriptomics of Kenyan, African American and Caucasian Women

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The current study determined the molecular fingerprints of TNBCs of women from kenya (KE) and compared them with those of African–American (AA) and Caucasian (CA) women.

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RNA sequencing analysis highlights the role of molecular alterations in TNBCs and the potential benefit of targeting pathways in this disease for the KE population as compared to AAs and CAs.

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The dysregulated genes and signaling pathways could contributes to the aggressive phenotypes of TNBCs of KE women.

Purpose

: Triple-negative breast cancer (TNBC) patients of various ethnic groups often have discrete clinical presentations and outcomes. Women of African descent have a disproportionately higher chance of developing TNBCs. The aim of the current study was to establish the transcriptome of TNBCs from Kenyan (KE) women of Bantu origin and compare it to those TNBCs of African-Americans (AA) and Caucasians (CA) for identifying KE TNBC-specific molecular determinants of cancer progression and potential biomarkers of clinical outcomes.

Patients and Methods

: Pathology-confirmed TNBC tissues from Kenyan women of Bantu origin (n = 15) and age and stage range matched AA (n = 19) and CA (n = 23) TNBCs of patients from Alabama were included in this study. RNA was isolated from paraffin-embedded tissues, and expression was analyzed by RNA sequencing.

Results

: At clinical presentation, young KE TNBC patients have tumors of higher stages. Differential expression analysis identified 160 up-regulated and 178 down-regulated genes in KE TNBCs compared to AA and CA TNBCs. Validation analyses of the TCGA breast cancer data identified 45 KE TNBC-specific genes that are involved in the apoptosis (ACTC1, ERCC6 and CD14), cell proliferation (UHRF2, KDM4C, UHMK1, KCNH5, KRT18, CSF1R and S100A13), and Wnt signaling (BCL9L) pathways.

Conclusions

: In this study, we identified biomarkers that are specific for KE TNBC patients of Bantu origin. Further study with a larger sample size of matched tumors could confirm our findings. If biologically confirmed, these molecular determinants could have clinical and biological implications and serve as targets for development of personalized therapeutics for KE TNBC patients.

Receptor-Defined Breast Cancer in Five East African Countries and Its Implications for Treatment: Systematic Review and Meta-Analysis

PURPOSE

Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) are determinants of treatment and mortality for patients with breast cancer (BC). In East Africa, the estimated 5-year survival (37.7%) is far lower than the US average (90%). This meta-analysis investigates BC receptor subtypes within five East African countries to ascertain cross-country patterns and prioritize treatment needs.

METHODS

From a PubMed search, January 1, 1998-June 30, 2019, for all English-only BC articles for Ethiopia, Kenya, Rwanda, Tanzania, and Uganda, eligible studies had receptor distributions for female BC samples ≥ 30 patients. Outcomes were proportions of ER+, PR+, and HER2-positive (HER2+), and/or molecular subtypes. Data included study characteristics and mean or median patient age. Using metaprop, Stata 16, we estimated pooled proportions (ES) with 95% CIs and assessed heterogeneity.

RESULTS

Among 36 BC studies with receptor data, 21 met criteria. Weighted mean age was 47.5 years and median, 48. Overall ES were as follows: 55% for ER-positive (ER+) (95% CI, 47 to 62), 23% for HER2+ (95% CI, 20 to 26), and 27% for triple-negative BC (TNBC) (95% CI, 23 to 32).

CONCLUSION

We found differences between countries, for example, lower distribution of TNBC in Ethiopia (21%) compared with Uganda (35%). ER+, the dominant BC subtype overall at 55%, emphasizes the need to prioritize endocrine therapy. Overall proportions of HER2+ BC (with or without ER+ or PR+), 23%, approached proportions of TNBC, 27%, yet HER2 testing and treatment were infrequent. Testing and reporting of receptor subtypes would promote delivery of more effective treatment reducing the mortality disparity.

Breast cancer pathology services in sub-Saharan Africa: a survey within population-based cancer registries

BACKGROUND

Pathologists face major challenges in breast cancer diagnostics in sub-Saharan Africa (SSA). The major problems identified as impairing the quality of pathology reports are shortcomings of equipment, organization and insufficiently qualified personnel. In addition, in the context of breast cancer, immunohistochemistry (IHC) needs to be available for the evaluation of biomarkers. In the study presented, we aim to describe the current state of breast cancer pathology in order to highlight the unmet needs.

METHODS

We obtained information on breast cancer pathology services within population-based cancer registries in SSA. A survey of 20 participating pathology centres was carried out. These centres represent large, rather well-equipped pathologies. The data obtained were related to the known population and breast cancer incidence of the registry areas.

RESULTS

The responding pathologists served populations of between 30,000 and 1.8 million and the centres surveyed dealt with 10-386 breast cancer cases per year. Time to fixation and formalin fixation time varied from overnight to more than 72 h. Only five centres processed core needle biopsies as a daily routine. Technical problems were common, with 14 centres reporting temporary power outages and 18 centres claiming to own faulty equipment with no access to technical support. Only half of the centres carried out IHC in their own laboratory. For three centres, IHC was only accessible outside of the country and one centre could not obtain any IHC results. A tumour board was established in 13 centres.

CONCLUSIONS

We conclude that breast cancer pathology services ensuring state-of-the-art therapy are only available in a small fraction of centres in SSA. To overcome these limitations, many of the centres require larger numbers of experienced pathologists and technical staff. Furthermore, equipment maintenance, standardization of processing guidelines and establishment of an IHC service are needed to comply with international standards of breast cancer pathology.

Androgen Receptor and ALDH1 Expression Among Internationally Diverse Patient Populations

Purpose

Population-based incidence rates of breast cancers that are negative for estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2/neu (triple-negative breast cancer [TNBC]) are higher among African American (AA) compared with white American (WA) women, and TNBC prevalence is elevated among selected populations of African patients. The extent to which TNBC risk is related to East African versus West African ancestry, and whether these associations extend to expression of other biomarkers, is uncertain.

Methods

We used immunohistochemistry to evaluate estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2/neu, androgen receptor and aldehyde dehydrogenase 1 (ALDH1) expression among WA (n = 153), AA (n = 76), Ethiopian (Eth)/East African (n = 90), and Ghanaian (Gh)/West African (n = 286) patients with breast cancer through an institutional review board–approved international research program.

Results

Mean age at diagnosis was 43, 49, 60, and 57 years for the Eth, Gh, AA, and WA patients, respectively. TNBC frequency was higher for AA and Gh patients (41% and 54%, respectively) compared with WA and Eth patients (23% and 15%, respectively; P < .001) Frequency of ALDH1 positivity was higher for AA and Gh patients (32% and 36%, respectively) compared with WA and Eth patients (23% and 17%, respectively; P = .007). Significant differences were observed for distribution of androgen receptor positivity: 71%, 55%, 42%, and 50% for the WA, AA, Gh, and Eth patients, respectively (P = .008).

Conclusion

Extent of African ancestry seems to be associated with particular breast cancer phenotypes. West African ancestry correlates with increased risk of TNBC and breast cancers that are positive for ALDH1.

Breast cancer care in northern Ethiopia - cross-sectional analysis

BACKGROUND

In Ethiopia, the incidence of new cases of breast cancer is currently increasing resulting to high rates of morbidity and mortality. Breast cancer is by far the most common cancer accounting for more than one out of three cancer cases in women and one out of every five in the general population. The study was conducted in University of Gondar Hospital cancer center, located in the North-West Ethiopia; to evaluate the clino-pathologic characteristics of breast cancer and care provided for patients.

METHODS

All biopsy proven breast cancer patients treated between 2016 and 2017, were identified and information regarding histology, stage, therapeutic procedure and follow up was retrospectively collected from their individual medical records and descriptive analysis was done.

RESULTS

Among 82 patients treated, 67 (82%) were women and 15 (18%) were men. The median age at the time of diagnosis was 45 years (25-82 years). Operation was performed for 56 (68%) patients. The predominant histology was ductal carcinoma in 61 patients (74%), followed by breast carcinoma of No Special Type (NST) in 17 (21%). The late presentation of the patients and the advanced stage at the time of presentation was observed in most of the patients. Chemotherapy was administered in 79 (96%) patients. Radiotherapy was not available in the hospital.

CONCLUSION

Breast cancer incidence is rising and becoming a major public health problem in Northern Ethiopia. Breast cancer care in northern-Ethiopia is limited in terms of both pathology, imaging and the offered treatment modalities, which need to be improved.

Breast and cervical cancer patients' experience in Addis Ababa city, Ethiopia: a follow-up study protocol

INTRODUCTION

Cancer is an emerging public health problem in Ethiopia, with breast and cervical cancers accounting for over half of all newly diagnosed cancers in women. The majority of women with breast and cervical cancer are diagnosed at late stage of the disease and most patients do not receive care consistent with global standards. However, little is known about the health-seeking behaviours, barriers to early detection and treatment, patient-reported outcomes, financial burden and survival of women with breast and cervical cancer in the country. Therefore, this study aims to document the experience of women with breast and cervical cancer from recognition of symptoms to diagnosis, treatment and survivorship/mortality in Addis Ababa city, Ethiopia.

METHODS AND ANALYSIS

A prospective follow-up study using mixed methods (both quantitative and qualitative) will be employed. All women newly diagnosed with breast and cervical cancer from 1 January, 2017 to 30 June 2018 in Addis Ababa will be included in the study. Interviewer-administered questionnaires will be used to collect information about medical consultations after recognition of symptoms, health-seeking behaviours, treatment received, barriers to early detection and treatment, and survivorship care. In-depth interview will be conducted on purposefully selected women with breast and cervical cancer. The primary outcomes of the study are time intervals (patient and diagnostic waiting times), stage at diagnosis and survival. Multivariable analysis will be employed to determine the contributions of independent variables on the outcomes of interest. HRs with 95% CIs will be calculated for time-to-event outcomes. Qualitative data will be analysed using thematic analysis.

ETHICS AND DISSEMINATION

This protocol is ethically approved by Institutional Review Board of Addis Ababa University. Verbal informed consent will be obtained from study participants. Results will be disseminated in international peer-reviewed journals and presented in relevant conferences.

Comparison of Receptor-Defined Breast Cancer Subtypes Between German and Sudanese Women: A Facility-Based Cohort Study

PURPOSE

The objective of this study was to compare tumor characteristics, biomarkers, and surrogate subtypes of breast cancer between Sudanese and German women.

METHODS

Tumor characteristics and immunohistochemistry markers (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor 2 [HER2]) were collected from the routine assessment of consecutive patients with invasive breast cancer diagnosed from 2010 to 2015 (Gezira University Pathology Laboratory, Gezira, Sudan) and from 1999 to 2013 (Breast Centre, Martin-Luther-University, Halle, Germany).

RESULTS

A total of 2,492 patients (German [n = 1,932] and Sudanese [n = 560]) were included. Age at diagnosis ranged from 20 to 94 years. Sudanese women were, on average, 10 years younger than German women, with a mean (± standard deviation) age of 48.8 (13.5) and 58.6 (12.4) years, respectively. The Sudanese women had a higher grade, larger tumor, and more lymph node positivity compared with German women. ER-, PR-, and HER2-negative proportions were 55%, 61.8%, and 71.3%, respectively, for Sudanese women versus 22.7%, 32.3%, and 82.5%, respectively, for German women. The triple-negative subtype was more prevalent in Sudanese women (34.5%) than in German women (14.2%). The strongest factor associated with ER-negative disease was grade III (odds ratio, 19.6; 95% CI 11.6 to 33.4; P < .001). Sudanese patients were at higher risk for ER-negative breast cancer, with an odds ratio of 2.01 ( P = .001; adjusted for age, size, nodal status, histologic type, and grade). Stratified by grade, the influence of origin was observed in grade I and grade II tumors, but not in grade III tumors.

CONCLUSION

Sudanese women had more aggressive tumor characteristics and unfavorable prognostic biomarkers. After adjustment, Sudanese origin was still associated with hormone receptor-negative disease, especially in grade I and II tumors. These findings suggest differences in tumor biology among these ethnic groups.

Characteristics and follow-up of metastatic breast cancer in Ethiopia: A cohort study of 573 women

OBJECTIVES

There is little information on characteristics, treatment and outcome of metastatic breast cancer (mBC) patients in low-income countries. This study aims to describe mBC in the setting of Ethiopia.

MATERIALS AND METHODS

A retrospective cohort study was conducted among all female mBC patients from the only oncologic hospital in Addis Ababa 01/2006 to 12/2010. Time between first metastasis and known death or loss to follow-up for more than six months as surrogate for death were used for Cox proportional hazards model.

RESULTS

A total of 573 patients were included; 188 (32.8%) women with de novo mBC (dnmBC) and 385 women with recurrent mBC (rmBC). The average age at time of first metastasis was 43.7 (standard deviation 11.9) years with an average survival probability of twelve months. Negative hormone receptor status, only present in 29% (Hazard ratio HR = 2.28 [95% confidence interval CI 1.56-3.32] p < 0.001), and grade 3 (HR = 1.72 [95% CI 1.15-2.55] p = 0.008) had significant influence on survival. Patients with initial bone metastasis (HR = 0.63 [95% CI 0.48-0.83] p = 0.001) had best chances of survival compared to more common initial visceral metastasis. About 35% of the patients received chemotherapy and 30.5% were on endocrine therapy.

CONCLUSION

The lower survival for mBC in Addis Ababa compared to that from Western countries is presumably due to the later presentation at the hospital and lack of standard therapy. An unexpected high proportion of patients with hormone receptor positive mBC encourage consequent utilization of endocrine therapy to improve the quality of palliative care in this cohort.

Pathology-Based Research in Africa

The process of conducting pathology research in Africa can be challenging. But the rewards in terms of knowledge gained, quality of collaborations, and impact on communities affected by infectious disease and cancer are great. This report reviews 3 different research efforts: fatal malaria in Malawi, mucosal immunity to HIV in South Africa, and cancer research in Uganda. What unifies them is the use of pathology-based approaches to answer vital questions, such as physiology, pathogenesis, predictors of clinical course, and diagnostic testing schemes.

Survival of breast cancer patients in rural Ethiopia

PURPOSE

To describe the histopathological characteristics and survival of female breast cancer (BC) patients in a rural setting with limited access to adjuvant treatment.

METHODS

A prospective study of 107 histologically confirmed BC patients treated with surgery from 2010 to 2016 from rural parts of western Ethiopia. Referral pathology was performed, and active follow-up was conducted. Adjusted cox regression analysis (hazard ratio [HR]) was performed.

RESULTS

The median age at diagnosis was 45 (16-83) years; 57% of the patients presented with cT3/4 tumors, 71% with clinically positive lymph nodes, 21% with HER2-overexpression (Dako3+) and 68% with grade 3 tumors. Estrogen and/or progesterone receptor expressions were present in 66% and triple-negative disease in 25%. The estimated 1- and 2-year overall survival probability rates were 78 and 53%, respectively. The 2-year survival for patients with clinically positive lymph nodes was 44% compared to 73% for patients with lymph node-negative disease (HR 2.44; 95% confidence interval [95% CI] 1.19-5.02). The corresponding 2-year survival for patients with cT4 tumors was 25% versus 68% for patients with cT1-2 tumors (cT1-3 vs. cT4 HR 3.86; 95% CI 1.82-13.63). The 2-year survival for patients with hormone receptor-negative disease was 40% compared to 59% for patients with hormone receptor-positive disease (HR 1.92; 95% CI 1.06-3.47).

CONCLUSION

The majority of breast cancer patients treated with surgery in rural parts of western Ethiopia are diagnosed at advanced stage and have hormone receptor-positive disease. Nearly half of the patients die within 2 years. These findings underscore the need for provision of adjuvant hormonal therapy and for the establishment of pathology service including hormone receptor testing.

Breast cancer in Ethiopia: evidence for geographic difference in the distribution of molecular subtypes in Africa

Background

Breast cancer is a heterogeneous disease with several morphological and molecular subtypes. Widely accepted molecular classification system uses assessment of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and proliferation marker Ki67. Few studies have been conducted on the incidence and molecular types of breast cancer in Sub-Saharan Africa. Previous studies mainly from Western and Central Africa, showed breast cancer to occur at younger ages and to present with aggressive features, such as high-grade, advanced stage and triple-negative phenotype (negative for ER, PR and HER2). Limited data from East Africa including Ethiopia however shows hormone receptor negative tumors to account for a lower proportion of all breast cancers than has been reported from elsewhere in Africa.

Methods

In this study from Tikur Anbessa Specialized Hospital, 114 breast cancer patients diagnosed between 2012 and 2015 were enrolled. ER, PR, Ki67 and HER2 receptor status were assessed using immunohistochemistry from tissue microarrays. FISH was used for assessment of gene amplification in all equivocal tumor samples and for confirmation in HER2-enriched cases.

Results

The distribution of molecular subtypes was: Luminal A: 40%; Luminal B: 26%; HER2-enriched: 10%; TNBC: 23%. ER were positive in 65% of all tumors and 43% the cases were positive for PR. There was statistically significant difference in median age at diagnosis between the molecular subtypes (P < 0.05). There was a bimodal distribution of molecular subtypes in different age ranges with Luminal B subtype being more common at younger ages (median = 36) and Luminal A subtype more prevalent at older ages (median = 42). There were no statistically significant differences in tumor grade, histology, and stage between the molecular subtypes of breast cancer.

Conclusion

The present study detected Luminal A breast cancer to be the most common subtype and reveals a relatively low rate of hormone receptor negative and TNBC. Our findings and results from other East African studies suggest geographic variability in the distribution of the molecular subtypes of breast cancer in Africa and hence have important clinical and policy implications for breast cancer control and treatment in Ethiopia.

Immunohistochemistry defined subtypes of breast cancer in 678 Sudanese and Eritrean women; hospitals based case series

BACKGROUND

Breast cancer is the most common malignancy accounting for 25% of all cancers in females. In Africa, breast cancer prevalence and mortality are steadily increasing. Knowledge of hormone receptors and human epidermal growth factor receptor-2 (HER-2) expressions are vital for breast cancer management plans and decision making. There is wide regional variation in the proportion of these biomarkers, especially in African countries. Hormone receptors positivity in indigenous African and African American women is considered to be low and triple negative breast cancer is a dominant phenotype. There is paucity of data regarding hormone receptors (ER and PR) and HER2 expressions in North-eastern Africa (Eritrea and Sudan). The purpose of this study was to evaluate the expression of ER, PR and HER2 in Eritrean and Sudanese case series and correlate these biomarkers with the clinicopathological profile.

METHOD

Clinicopathologic data of patients were collected from clinical records. Immunohistochemistry biomarkers (ER, PR, and HER2) were assessed in consecutive female patients who had been diagnosed with invasive breast cancer from 2011 to 2015 in Gezira University Pathology Laboratory, the Sudan and National Health laboratory, Asmara, Eritrea.

RESULTS

There were 678 cases involved in this study. The mean age was 48.8 years with ±0.53 standard error of the mean. Two-thirds of the case were ≤50 years. Invasive ductal carcinoma, no special type was the most dominant histologic type (86%) in both study groups. The majority of cases (70%) had tumour stage pT2 and pT3 and about 50% had lymph node involvement. Less than 5% of the cases had well-differentiated tumours. The ER, PR and HER2 positive rates were 45%, 32%, and 29%, respectively. The proportion of luminal-A like, luminal-B like, HER2 enriched and TNBC were 37%, 13%, 16% and 34%, respectively. Fisher extract analysis showed age (p = .015), tumour size (p = .041), and histologic grade (p = .000) were significantly associated with intrinsic subtypes. Furthermore, Logistic regression analysis stratified by origin, age, tumour size, lymph-node metastasis and grade indicated that younger women age (≤50 years) and grade III tumours were more likely to be diagnosed with ER negative breast cancer.

CONCLUSION

Most of Sudanese and Eritrean women were diagnosed at younger age and with unfavourable prognostic clinicopathologic prognostic markers. TNBC is more frequent in this cohort study; patients with grade III tumours and young age are more likely to be hormone receptors negative. Therefore, routine determination of hormone receptors is warranted for appropriate targeted therapy.

Breast cancer in Angola, molecular subtypes: a first glance

Purpose

The aim of this study was to investigate the breast cancer (BC) molecular subtypes according to its surrogate immunohistochemistry (IHC) markers. We conducted a preliminary study, to correlate the clinical pathological profiles and molecular subtypes of breast cancer in Luanda, Angola.

Methods

From January 2011 to 30 December 2014, 140 consecutive cases of microscopically confirmed invasive breast carcinoma were classified regarding histology and IHC (ER, PR, HER2, and Ki-67). Surrogate molecular subtypes were classified according to ESMO recommendations.

Results

All patients were female; the median age was 47 years (24–84 years). Invasive carcinoma NST was the most common type (91.4%) and grade 2 was prevalent (70.7%). Most tumours were locally advanced (stage III – 65% and stage IV – 3.6%). In 140 studied cases, 74 (52.8%) malignancies were hormone receptor positive; 25.7% were luminal A like, 19.3% luminal B and HER2 negative like, 7.9% luminal B and HER2-positive like, 15.7% HER2 positive, and 31.4% were triple negative.

Conclusion

Women’s BC in Luanda-Angola is diagnosed at a young age and at an advanced stage. The two predominant molecular subtypes are HR positive and triple negative. The percentage of HER2-positive BC cases was high. Determining the molecular subtype using surrogate IHC markers has important treatment and prognostic implications for Angolan women with BC. There is an urgent need to study a prospective BC series in order to confirm the present results.

First report on molecular breast cancer subtypes and their clinico-pathological characteristics in Eastern Morocco: series of 2260 cases

BACKGROUND

Breast cancer is the most frequent malignancy among women in Eastern Morocco. In this paper, we provide the first report on molecular breast cancer subtypes in this region. This is the largest population-based study on breast cancer among Moroccan women.

METHODS

We analyzed 2260 breast cancer cases diagnosed at the Hassan II Regional Oncology Center between October 2005 and December 2012. Clinico-pathological and therapeutic features were studied. Molecular subtypes were determined and their associations with the clinico-pathological characteristics of the tumors were examined.

RESULTS

The mean age at diagnosis was 48.7 years ±11.4. Invasive ductal carcinoma was the predominant histological type (77.1%), followed by lobular invasive carcinoma (15.3%). The mean size of breast tumors was 3.5 cm ± 1.96, and 84% of our patients are diagnosed with tumors of more than 2 cm. Histological grade II tumors were the most frequent (70.4%), followed by advanced histological grade (18%). Lymph node positive tumors were observed in 64.8% of cases and 29.3% of patients had distant metastasis. Most tumors were hormone receptor-positive (73%) and 28.6% were HER2 positive. 86.1% of patients with hormone receptor-positive breast cancer were given hormone therapy, while 68.9% of patients with HER2+ breast cancer received targeted therapy with Herceptin. Luminal A was the commonest molecular subtype, followed by Luminal B, Triple Negative and HER2. The highest prevalence of premenopausal patients was observed in Triple Negative subtype (72.2%), followed by HER2 (64.1%), Luminal B (62.2%), and Luminal A (55.1%). Luminal B subtype had a poorer prognosis than Luminal A. Compared with Triple Negative, HER2 subtype tend to spread more aggressively and is associated with poorer prognosis.

CONCLUSIONS

Unlike Western countries, breast cancer occurs at an earlier age and is diagnosed at a more advanced stage in Eastern Morocco. In this region, hormone receptor-positive tumors are predominant and so the majority of breast cancer patients should benefit from hormone therapy. HER2 subtype presents an aggressive tendency, suggesting the importance of anti-HER2 therapy. This study will contribute in developing appropriate screening and cancer management strategies in Eastern Morocco.

Comparative Analysis of Breast Cancer Phenotypes in African American, White American, and West Versus East African patients: Correlation Between African Ancestry and Triple-Negative Breast Cancer

INTRODUCTION

Triple-negative breast cancer (TNBC) is more common among African American (AA) and western sub-Saharan African breast cancer (BC) patients compared with White/Caucasian Americans (WA) and Europeans. Little is known about TNBC in east Africa.

METHODS

Invasive BC diagnosed 1998-2014 were evaluated: WA and AA patients from the Henry Ford Health System in Detroit, Michigan; Ghanaian/west Africans from the Komfo Anokye Teaching Hospital in Kumasi, Ghana; and Ethiopian/east Africans from the St. Paul's Hospital Millennium Medical College in Addis Ababa, Ethiopia. Histopathology and immunohistochemistry for estrogen receptor (ER), progesterone receptor (PR), and HER2/neu expression was performed in Michigan on formalin-fixed, paraffin-embedded samples from all cases.

RESULTS

A total of 234 Ghanaian (mean age 49 years), 94 Ethiopian (mean age 43 years), 272 AA (mean age 60 years), and 321 WA (mean age 62 years; p = 0.001) patients were compared. ER-negative and TNBC were more common among Ghanaian and AA compared with WA and Ethiopian cases (frequency ER-negativity 71.1 and 37.1 % vs. 19.8 and 28.6 % respectively, p < 0.0001; frequency TNBC 53.2 and 29.8 % vs. 15.5 and 15.0 %, respectively, p < 0.0001). Among patients younger than 50 years, prevalence of TNBC remained highest among Ghanaians (50.8 %) and AA (34.3 %) compared with WA and Ethiopians (approximately 16 % in each; p = 0.0002).

CONCLUSIONS

This study confirms an association between TNBC and West African ancestry; TNBC frequency among AA patients is intermediate between WA and Ghanaian/West Africans consistent with genetic admixture following the west Africa-based trans-Atlantic slave trade. TNBC frequency was low among Ethiopians/East Africans; this may reflect less shared ancestry between AA and Ethiopians.

Aggressive breast cancer in western Kenya has early onset, high proliferation, and immune cell infiltration

Background

Breast cancer incidence and mortality vary significantly among different nations and racial groups. African nations have the highest breast cancer mortality rates in the world, even though the incidence rates are below those of many nations. Differences in disease progression suggest that aggressive breast tumors may harbor a unique molecular signature to promote disease progression. However, few studies have investigated the pathology and clinical markers expressed in breast tissue from regional African patient populations.

Methods

We collected 68 malignant and 89 non-cancerous samples from Kenyan breast tissue. To characterize the tumors from these patients, we constructed tissue microarrays (TMAs) from these tissues. Sections from these TMAs were stained and analyzed using immunohistochemistry to detect clinical breast cancer markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 receptor (HER2) status, Ki67, and immune cell markers.

Results

Thirty-three percent of the tumors were triple negative (ER-, PR-, HER2-), 59 % were ER+, and almost all tumors analyzed were HER2-. Seven percent of the breast cancer patients were male, and 30 % were <40 years old at diagnosis. Cancer tissue had increased immune cell infiltration with recruitment of CD163+ (M2 macrophage), CD25+ (regulatory T lymphocyte), and CD4+ (T helper) cells compared to non-cancer tissue.

Conclusions

We identified clinical biomarkers that may assist in identifying therapy strategies for breast cancer patients in western Kenya. Estrogen receptor status in particular should lead initial treatment strategies in these breast cancer patients. Increased CD25 expression suggests a need for additional treatment strategies designed to overcome immune suppression by CD25+ cells in order to promote the antitumor activity of CD8+ cytotoxic T cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2204-6) contains supplementary material, which is available to authorized users.

The association of area-level social class and tobacco use with adverse breast cancer characteristics among white and black women: evidence from Maryland, 1992-2003

Background

In breast cancer, worse disease characteristics are associated with fewer social resources and black race. However, it is unknown whether social gradients have similar impact across race, and whether behaviors, including tobacco use, may explain a portion of the social gradient.

Methods

We modeled relationships between area-level social class, tobacco spending and tumor characteristics, using 50,062 white and black cases diagnosed from 1992–2003 in Maryland, a racially and economically diverse state on the east coast of the United States. Multi-level models estimated the effect of area-level social class and tobacco consumption on tumor grade, size, and stage at diagnosis.

Results

Adjusting for race, age and year of diagnosis, higher social class was associated with lower risk for tumors with histological grade 3 or 4 (O.R. 0.96, 95% C.I. 0.94,0.99), those diagnosed at SEER stage 2 or later (O.R. 0.89, 95% C.I. 0.86, 0.91), and tumor size >2 cm (O.R. 0.87, 95% C.I. 0.84, 0.90). Higher tobacco spending was associated with higher risk for higher grade (O.R. 1.01, 1.00, 1.03) and larger tumors (O.R. 1.03, 95% C.I. 1.01, 1.06), but was not statistically significantly related to later stage (O.R. 1.00, 95% C.I. 0.98, 1.02). Social class was less protective for black women, but tobacco effects were not race-specific.

Conclusions

Results suggest that in one U.S. geographic area, there is a differential protection from social class for black and white women, supporting use of intersectionality theory in breast cancer disparities investigations. Area-level tobacco consumption may capture cases’ direct use and second hand smoke exposure, but also may identify neighborhoods with excess cancer-related behavioral or environmental exposures, beyond those measured by social class. Given the growing global burden of both tobacco addiction and aggressive breast cancer, similar investigations across diverse geographic areas are warranted.