Breast Cancer Genetic Testing Among African Patients With Breast Cancer: Deoxyribonucleic Acid Extraction From Tumor Tissue and International Multidisciplinary Partnerships

Screening and Testing for Homologous Recombination Repair Deficiency (HRD) in Breast Cancer: an Overview of the Current Global Landscape

PURPOSE OF REVIEW

Homologous recombination repair deficiency (HRD) increases breast cancer susceptibility and influences both prophylactic and active management of breast cancer. This review evaluates HRD testing and the therapeutic implications of HRD in a global context.

RECENT FINDINGS

Ongoing research efforts have highlighted the importance of HRD beyond BRCA1/2 as a potential therapeutic target in breast cancer. However, despite the improved affordability of next-generation sequencing (NGS) and the discovery of PARP inhibitors, economic and geographical barriers in access to HRD testing and breast cancer screening do not allow all patients to benefit from the personalized treatment approach they provide. Advancements in HRD testing modalities and targeted therapeutics enable tailored breast cancer management. However, inequalities in access to testing and optimized treatments are contributing to widening health disparities globally.

Breast Cancer Germline Genetic Counseling and Testing for Populations of African Heritage Globally: A Scoping Review on Research, Practice, and Bioethical Considerations

PURPOSE

Despite the disproportionately high risk of breast cancer among women of African heritage, little is known about the facilitators and barriers to implementing germline genetic testing and counseling (GT/C).

METHODS

This scoping review followed guidelines recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. Published manuscripts from database inception through 2021 were sourced from PubMed, Cumulative Index to Nursing and Allied Health Literature via EBSCO, Embase, Cochrane Library, and Scopus. Search terms were used to retrieve articles addressing (1) African heritage, (2) breast cancer, and (3) GT or GC. The screening involved abstract and title review and full-text review. Data were extracted for all articles meeting the inclusion criteria.

RESULTS

A total of 154 studies were included. Most studies that took place were conducted in the United States (71.4%), and most first authors (76.9%) were from the United States. GT was conducted in 73 (49.7%) studies. BRCA1/BRCA2 were the most commonly studied genes for germline mutations. GC was conducted in 49 studies (33.3%), and perspectives on GC were evaluated in 43 (29.3%). The use of racial/ethnic categories varied broadly, although African American was most common (40.1%). Racism was mentioned in three studies (2.0%).

CONCLUSION

There is a growing body of literature on GT/C for breast cancer in women of African heritage. Future studies on GT/C of African populations should consider increased clarity around racial/ethnic categorizations, continued community engagement, and intentional processes for informed consent.

Breast Cancer Risk in Women from Ghana Carrying Rare Germline Pathogenic Mutations

BACKGROUND

Risk estimates for women carrying germline mutations in breast cancer susceptibility genes are mainly based on studies of European ancestry women.

METHODS

We investigated associations between pathogenic variants (PV) in 34 genes with breast cancer risk in 871 cases [307 estrogen receptor (ER)-positive, 321 ER-negative, and 243 ER-unknown] and 1,563 controls in the Ghana Breast Health Study (GBHS), and estimated lifetime risk for carriers. We compared results with those for European, Asian, and African American ancestry women.

RESULTS

The frequency of PV in GBHS for nine breast cancer genes was 8.38% in cases and 1.22% in controls. Relative risk estimates for overall breast cancer were: (OR, 13.70; 95% confidence interval (CI), 4.03-46.51) for BRCA1, (OR, 7.02; 95% CI, 3.17-15.54) for BRCA2, (OR, 17.25; 95% CI, 2.15-138.13) for PALB2, 5 cases and no controls carried TP53 PVs, and 2.10, (0.72-6.14) for moderate-risk genes combined (ATM, BARD1, CHEK2, RAD51C, RAD52D). These estimates were similar to those previously reported in other populations and were modified by ER status. No other genes evaluated had mutations associated at P < 0.05 with overall risk. The estimated lifetime risks for mutation carriers in BRCA1, BRCA2, and PALB2 and moderate-risk genes were 18.4%, 9.8%, 22.4%, and 3.1%, respectively, markedly lower than in Western populations with higher baseline risks.

CONCLUSIONS

We confirmed associations between PV and breast cancer risk in Ghanaian women and provide absolute risk estimates that could inform counseling in Ghana and other West African countries.

IMPACT

These findings have direct relevance for breast cancer genetic counseling for women in West Africa.

Incidence of breast cancer subtypes in immigrant and non-immigrant women in Norway

BACKGROUND

Breast cancer incidence differs between non-immigrants and immigrants from low- and middle-income countries. This study investigates whether immigrants also have different subtype-specific incidences.

METHODS

We used national health registries in Norway and calculated subtype-specific incidence rate ratios (IRRs) for invasive breast cancer among women aged 20-75 and 20-49 years between 2005 and 2015. Immigrant groups were classified by country of birth broadly defined based on WHO regional groupings. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A-like (ER+ PR+ HER2-), luminal B-like/HER2- (ER+ PR- HER2-), luminal B-like/HER2+ (ER+ PR any HER2+), HER2+ (ER-PR-HER2+) and triple-negative breast cancer (TNBC) (ER-PR-HER2-).

RESULTS

Compared to non-immigrants, incidence of the luminal A-like subtype was lower in immigrants from Sub-Saharan Africa (IRR 0.43 95% CI 0.28-0.66), South East Asia (IRR 0.63 95% CI 0.51-0.79), South Asia (IRR 0.67 95% CI 0.52-0.86) and Eastern Europe (IRR 0.86 95% CI 0.76-0.99). Immigrants from South Asia had higher rates of HER2 + tumors (IRR 2.02 95% CI 1.26-3.23). The rates of TNBC tended to be similar regardless of region of birth, except that women from South East Asia had an IRR of 0.54 (95% CI 0.32-0.91).

CONCLUSIONS

Women from Eastern Europe, Sub-Saharan Africa and Asia had different subtype-specific incidences compared to women from high-income countries (including non-immigrants). These differences in tumor characteristics between immigrant groups should be taken into consideration when planning preventive or screening strategies.

Assessment of Breast Cancer Management in Sub-Saharan Africa

PURPOSE

To document progress and bottlenecks in breast cancer management in sub-Saharan Africa, subsequent to a 2013 pilot survey conducted through the African Organization for Research and Treatment in Cancer (AORTIC) network.

METHODS

An anonymous survey of breast cancer management was conducted in 2018 among AORTIC members. Results concerning respondent specialty, access to tumor boards, treatment accessibility, diagnostic services, and factors influencing treatment outcomes were compared with the 2013 findings.

RESULTS

Thirty-seven respondents from 30 facilities in 21 sub-Saharan Africa countries responded. The majority (92%) were clinical oncologists. Radiotherapy facilities were available in 70% of facilities. Seventy-eight percent of these had linear accelerators, and 42% had cobalt⁶⁰ machines. Eighty percent of facilities had multidisciplinary tumor boards. Immunohistochemistry was routinely performed in 74% of facilities, computed tomography scan in 90%, bone scan in 16%, and positron emission tomography scans in 5%. Anthracyclines, taxanes, tamoxifen, letrozole, anastrozole, and zoledronic acid were available in the majority; trastuzumab, fertility, and genetic counseling were available in 66%, 58%, and 16%, respectively. There were a 50% increase in oncologist respondents over 2013 and a > 50% increase in radiotherapy facilities, particularly linear accelerators. Availability of trastuzumab, aromatase inhibitors, and taxanes increased. Immunohistochemistry capacity remained the same, whereas facilities harvesting at least 10 axillary lymph nodes increased. Bone scan facilities decreased. Responses suggested improved diagnostic services, systemic therapies, and radiotherapy. Sociocultural and economic barriers, system delays, and advanced stage at presentation remain.

CONCLUSION

Clinicians in sub-Saharan Africa have basic tools to improve breast cancer outcomes, recording positive strides in domains such as radiotherapy and systemic therapy. Socioeconomic and cultural barriers and system delays persist. Workforce expansion must be prioritized to improve quality of care to improve outcomes.

This study highlights the current state of breast cancer management in Sub Saharan Africa, documenting key advancements , challenges and bottlenecks encountered in the sub region. Aside the major aspects of management, pertinent areas such as multidisciplinary tumour board engagements, fertility , genetic counselling and factors affecting outcome were explored. Majority of institutions manage breast cancer patients within a multidisciplinary setting using standard treatment guidelines. The high out of pocket cost of cancer treatment and advanced stage at presentation transcends in many sub Saharan countries negatively impacting outcomes. These results should serve as a benchmark to stakeholders , to guide urgent interventions required to further improve outcomes.

Identification of BRCA1/2 p.Ser1613Gly, p.Pro871Leu, p.Lys1183Arg, p.Glu1038Gly, p.Ser1140Gly, p.Ala2466Val, p.His2440Arg variants in women under 45 years old with breast nodules suspected of having breast cancer in Burkina Faso

Breast cancer is the top cause of cancer mortality among women in the world and the second in Africa. The aims of this study were to: i) identify women with breast nodules suspected of having breast cancer ii) sequence the BRCA1 and BRCA2 genes and iii) screen mutations. From 2015 to 2016, 112 women aged from 35 to 44 years, who had come for consultation in the gynecology/obstetrics and the oncology department of the University Hospital Yalgado Ouedraogo, voluntarily agreed to participate to this study. Whole blood was collected from those with mammary nodules. The genomic DNA was extracted using Qiagen kit. FAST KAPA was used for genomic DNA amplification and the purified PCR products were analyzed by direct sequencing using Big Dye v1.1 and ABI 3730 automated sequencer. Nucleotides substitutions were determined. We identified BRCA1 SNPs rs1799966, rs799917, rs16942, rs16941, rs2227945, and BRCA2 SNPs rs169547, rs4986860. These identified variants are found mostly in cases of benign tumors of breast or ovarian cancer with familial history of breast cancer. This study in Burkina-Faso, is the basis for improved and more specific genetic testing, and suggests that additional genes contributing to an increased risk of breast cancer should be analyzed.

Sistas Taking a Stand for Breast Cancer Research (STAR) Study: A Community-Based Participatory Genetic Research Study to Enhance Participation and Breast Cancer Equity among African American Women in Memphis, TN

African American women are substantially underrepresented in breast cancer genetic research studies and clinical trials, yet they are more likely to die from breast cancer. Lack of trust in the medical community is a major barrier preventing the successful recruitment of African Americans into research studies. When considering the city of Memphis, TN, where the percentage of African Americans is significantly higher than the national average and it has a high rate of breast cancer mortality inequities among African American women, we evaluated the feasibility of utilizing a community-based participatory (CBPR) approach for recruiting African American women into a breast cancer genetic study, called the Sistas Taking A Stand for Breast Cancer Research (STAR) study. From June 2016 and December 2017, African American women age 18 and above were recruited to provide a 2 mL saliva specimen and complete a health questionnaire. A total of 364 African American women provided a saliva sample and completed the health questionnaire. Greater than 85% agreed to be contacted for future studies. Educational workshops on the importance of participating in cancer genetic research studies, followed by question and answer sessions, were most successful in recruitment. Overall, the participants expressed a strong interest and a willingness to participate in the STAR study. Our findings highlight the importance of implementing a CBPR approach that provides an educational component detailing the importance of participating in cancer genetic research studies and that includes prominent community advocates to build trust within the community.