Breast cancer in Zimbabwe: patterns of care and correlates of adherence in a national referral hospital radiotherapy center cohort from 2014 to 2018

Radiation Therapy for Breast Cancer in Africa

Purpose

Although radiation therapy is an effective treatment for breast cancer, it has a low rate of use in African countries. A systematic review was undertaken to investigate studies that used radiation therapy as a treatment modality for patients with breast cancer in Africa, focusing on survival outcomes, adverse effects, radiation therapy techniques, fractionation schedules, and effectiveness of radiation therapy.

Methods and Materials

We conducted a comprehensive literature search for studies that treated breast cancer with radiation therapy, using different electronic databases (PubMed, Scopus, and EBSCOhost) up to February 2023. The output was exported to a reference management system for analyses.

Results

The literature search primarily identified 3804 records from Scopus (2427), PubMed (982), and EBSCOhost (395). Based on the inclusion and exclusion criteria, 19 articles were finally included in this systematic review. Most of the studies published were conducted in North Africa (63%), followed by West Africa (21%) and Southeast Africa (16%). Most centers employed external beam radiation therapy to deliver radiation therapy to patients with breast cancer with the standard fractionation size of 50 Gy in 25 fractions. The long-term outcomes with regards to adverse effect suggests that radiation therapy was fairly tolerated among patients with breast cancer.

Conclusions

The reports provide substantial evidence that there are limited number of published studies on the use of radiation therapy for breast cancer treatment in Africa, as well as lower overall survival rate compared with developed countries. To improve breast cancer survivorship, it is necessary for government and other health care planners to provide more radiation therapy resources and implement training programs for personnels.

High-value breast cancer care within resource limitations

Breast cancer care is a costly global health issue where effective management depends on early detection and treatment. A breast cancer diagnosis can result in financial catastrophe especially in low- and middle-income countries (LMIC). Large inequities in breast cancer care are observed and represent a global challenge to caregivers and patients. Strategies to improve early diagnosis include awareness and clinical breast examination in LMIC, and screening in high-income countries (HIC). The use of clinical guidelines for the management of breast cancer is needed. Adapted guidelines from HIC can address disparities in populations with limited resources. Locally developed strategies still provide effective guidance in improving survival. Integrated practice units (IPU) with timely multidisciplinary breast care conferences and patient navigators are required to achieve high-value, personalized breast cancer management in HIC as well as LMIC. Breast cancer patient care should include a quality of life evaluation using ideally patient-reported outcomes (PROM) and experience measurements (PREM). Evaluation of breast cancer outcomes must include the financial cost of delivered care. The resulting value perspective should guide resource allocation and program priorities. The value of care must be improved by translating the findings of social and economic research into practice and resolving systemic inequity in clinical breast cancer research. Cancer survivorship programs must be put in place everywhere. The treatment of patients with metastatic breast cancer must require more attention in the future, especially in LMIC.

A model to enhance breast cancer screening among rural women aged 40-75 years in Sub-Saharan Africa (SSA): A scoping review

INTRODUCTION AND BACKGROUND

It is claimed that very little research has been done in Africa on breast cancer screening to identify the best method that can be adopted to have early detection of the malignancy. Breast cancer is a growing burden globally and in Sub-Saharan Africa (SSA). There is a rise in breast cancer mortality in SSA. This is caused by limited breast cancer screening or early detection practices due to limited resources which makes mammography unaffordable by the majority of women. This problem is more prevalent in elderly women living in rural areas where limited or no breast cancer screening is taking place. Downstaging which is context-specific is recommended for African countries but more studies are required to confirm its effectiveness.

OBJECTIVES

This review aims to identify the gaps in the literature focusing on strategies to enhance breast cancer screening among elderly women aged 40-75 years who reside in rural areas.

INCLUSION CRITERIA

The articles to be reviewed should focus on screening for the elderly women population that reside in rural areas and should fall within the age range of 40-75 years. Other phrases that can be included instead of breast cancer screening could be early detection measures, early diagnosis, or downstaging.

METHODOLOGY

The methodology was guided by the published manual for Joana Briggs Institute for scoping reviews. A search of the relevant studies was conducted on 4 October 2022 across PubMed, SCOPUS, Embase, and EBSCO Host databases. The systematic literature search strategy was developed and carried out using the Medical Subject Heading (MeSH) database. The eligibility criteria were developed using the Participants, Concept, and Context framework. Only articles written in English and published between 2010 and 2022 were considered. Removal of duplications was done first, followed by screening using the article title and abstract and then using full-text articles. The results of the search were profiled on the PRISMAScR flow chart diagram. Themes were identified from the conclusions of the reviewed studies.

RESULTS

After searching 78 citations were identified. These were screened and only 8 were left after the different stages of screening. The reviewed articles were published between 2010 and 2020. The majority (75%) of the studies were surveys except for two which were qualitative and all done in Kenya. No mixed methodology study was done. No study focused on developing a model to enhance breast cancer screening among rural women aged 40-75 years although there are very few countries in Africa with established nationwide breast cancer screening guidelines.

CONCLUSION

There are limited studies done on breast cancer screening of elderly rural women in SSA. No study was done to identify a model to enhance breast cancer screening among the rural elderly women population. None of the reviewed studies utilized the mixed methodology design to have an in-depth context-specific understanding to pave the way for the implementation of downstaging which is recommended for countries with limited resources.

CONTRIBUTION

The scoping review indicated the gap in research in terms of breast cancer screening among women aged 40-75 years who reside in rural areas and highlighted the future need for such studies to make downstaging effective.

Pharmacogenetics and pharmacokinetics of tamoxifen in a Zimbabwean breast cancer cohort

Tamoxifen is the most used hormonal therapy for oestrogen receptor-positive breast cancer. CYP2D6 is the main enzyme in the metabolic pathway of tamoxifen to endoxifen. Variations in endoxifen plasma concentrations are associated with CYP2D6 polymorphisms. This study aimed to determine the association between the CYP2D6 polymorphisms and endoxifen plasma concentrations in a cohort of Zimbabwean breast cancer patients (n = 40). TaqMan genotyping and copy number assays were done to determine CYP2D6 genotypes. Tamoxifen and metabolites were quantitated using LC-MS/MS. The population had high frequencies of the CYP2D6 reduced function alleles, *17 (15%) and *29 (18%). The median endoxifen concentration was 4.78 ng/mL, and in 55% of the patients, mostly intermediate metabolizers were below the endoxifen therapeutic threshold of 5.97 ng/mL. The CYP2D6 phenotypes and activity scores were significantly associated with endoxifen plasma concentrations (P = 0.0151) and with endoxifen to N-desmethyl-tamoxifen ratios (P = 0.0006).

Discordance between PAM50 intrinsic subtyping and immunohistochemistry in South African women with breast cancer

PURPOSE

Breast cancer is a heterogeneous disease with different gene expression profiles, treatment options and outcomes. In South Africa, tumors are classified using immunohistochemistry. In high-income countries multiparameter genomic assays are being utilized with implications for tumor classification and treatment.

METHODS

In a cohort of 378 breast cancer patients from the SABCHO study, we investigated the concordance between tumor samples classified by IHC and the PAM50 gene assay.

RESULTS

IHC classified patients as ER-positive (77.5%), PR-positive (70.6%), and HER2-positive (32.3%). These results, together with Ki67, were used as surrogates for intrinsic subtyping, and showed 6.9% IHC-A-clinical, 72.7% IHC-B-clinical, 5.3% IHC-HER2-clinical and 15.1% triple negative cancer (TNC). Typing using the PAM50 gave 19.3% luminal-A, 32.5% luminal-B, 23.5% HER2-enriched and 24.6% basal-like. The basal-like and TNC had the highest concordance, while the luminal-A and IHC-A group had the lowest concordance. By altering the cutoff for Ki67, and realigning the HER2/ER/PR-positive patients to IHC-HER2, we improved concordance with the intrinsic subtypes.

CONCLUSION

We suggest that the Ki67 be changed to a cutoff of 20-25% in our population to better reflect the luminal subtype classifications. This change would inform treatment options for breast cancer patients in settings where genomic assays are unaffordable.

Hypofractionation in Breast Cancer Radiotherapy Across World Bank Income Groups: Results of an International Survey

PURPOSE

Hypofractionated breast radiotherapy has been found to be equivalent to conventional fractionation in many clinical trials. Using data from the European Society for Radiotherapy and Oncology Global Impact of Radiotherapy in Oncology survey, we identified preferences for hypofractionation in breast cancer across World Bank income groups and the perceived facilitators and barriers to its use.

MATERIALS AND METHODS

An international, electronic survey was administered to radiation oncologists from 2018 to 2019. Demographics, practice characteristics, preferred hypofractionation regimen for specific breast cancer scenarios, and facilitators and barriers to hypofractionation were reported and stratified by World Bank income groups. Variables associated with hypofractionation were assessed using multivariate logistic regression models.

RESULTS

One thousand four hundred thirty-four physicians responded: 890 (62%) from high-income countries (HICs), 361 (25%) from upper-middle-income countries (UMICs), 183 (13%) from low- and lower-middle-income countries (LLMICs). Hypofractionation was preferred most frequently in node-negative disease after breast-conserving surgery, with the strongest preference reported in HICs (78% from HICs, 54% from UMICs, and 51% from LLMICs, P < .001). Hypofractionation for node-positive disease postmastectomy was more frequently preferred in LLMICs (28% from HICs, 15% from UMICs, and 35% from LLMICs, P < .001). Curative doses of 2.1 to < 2.5 Gy in 15-16 fractions were most frequently reported, with limited preference for ultra-hypofractionation, but significant variability in palliative dosing. In adjusted analyses, UMICs were significantly less likely than LLMICs to prefer hypofractionation across all curative clinical scenarios, whereas respondents with > 1 million population catchments and with intensity-modulated radiotherapy were more likely to prefer hypofractionation. The most frequently cited facilitators and barriers were published evidence and fear of late toxicity, respectively.

CONCLUSION

Preference for hypofractionation varied for curative indications, with greater acceptance in earlier-stage disease in HICs and in later-stage disease in LLMICs. Targeted educational interventions and greater inclusivity in radiation oncology clinical trials may support greater uptake.