Screening mammography with special reference to guidelines in South Africa

Implementation of multigene panel testing for breast and ovarian cancer in South Africa: A step towards excellence in oncology for the public sector

Translation of genomic knowledge into public health benefits requires the implementation of evidence-based recommendations in clinical practice. In this study, we moved beyond BRCA1/2 susceptibility testing in breast and ovarian cancer patients to explore the application of pharmacogenetics across multiple genes participating in homologous recombination DNA damage repair. This involved the utilisation of next-generation sequencing (NGS) at the intersection of research and service delivery for development of a comprehensive genetic testing platform in South Africa. Lack of international consensus regarding risk categorization of established cancer susceptibility genes and the level of evidence required for prediction of drug response supported the development of a central database to facilitate clinical interpretation. Here we demonstrate the value of this approach using NGS to 1) determine the variant spectrum applicable to targeted therapy and implementation of prevention strategies using the 15-gene Oncomine™ BRCA Expanded Panel, and 2) searched for novel and known pathogenic variants in uninformative cases using whole exome sequencing (WES). Targeted NGS performed as a routine clinical service in 414 South African breast and/or ovarian cancer patients resulted in the detection of 48 actionable variants among 319 (15%) cases. BRCA1/2-associated cancers were identified in 70.8% of patients (34/48, including two double-heterozygotes), with the majority (35.3%, 12/34) representing known South African founder variants. Detection of actionable variants in established non-BRCA1/2 risk genes contributed 29% to the total percentage (14/48), distributed amongst ATM, CHEK2, BARD1, BRIP1, PALB2 and TP53. Experimental WES using a virtually constructed multi-cancer NGS panel in 16 genetically unresolved cases (and four controls) revealed novel protein truncating variants in the basal cell carcinoma gene PTCH1 (c.4187delG) and the signal transmission and transduction gene KIT (c.930delA) involved in crucial cellular processes. Based on these findings, the most cost-effective approach would be to perform BRCA1/2 founder variant testing at referral, followed by targeted multigene panel testing if clinically indicated and addition of WES in unresolved cases. This inventive step provides a constant flow of new knowledge into the diagnostic platform via a uniquely South African pathology-supported genetic approach implemented for the first time in this context to integrate research with service delivery.

Breast cancer screening in sub-Saharan Africa: a systematic review and ethical appraisal

BACKGROUND

The aim of this systematic review was to evaluate the evidence and clinical outcomes of screening interventions and implementation trials in sub-Saharan Africa (SSA) and also appraise some ethical issues related to screening in the region through quantitative and qualitative narrative synthesis of the literature.

METHODS

We searched Pubmed, OvidMEDLINE, Embase, and Web of Science to identify studies published on breast cancer screening interventions and outcomes in SSA. Descriptive statistics were used to summarize the frequency and proportions of extracted variables, and narrative syntheses was used to evaluate the clinical outcomes of the different screening modalities. The mixed methods appraisal tool was used to assess the quality of studies included in the review.

RESULTS

Fifteen studies were included, which consisted of 72,572 women in ten countries in SSA. 63% (8/15) of the included publications evaluated Clinical Breast Examination (CBE), 47% (7/15) evaluated mammography and 7% (1/15) evaluated ultrasound screening. The cancer detection rate was < 1/1000 to 3.3/1000 and 3.3/100 to 56/1000 for CBE and mammography screening respectively. There was a lot of heterogeneity in CBE methods, target age for screening and no clear documentation of screening interval. Cost-effective analyses showed that CBE screening linked to comprehensive cancer care is most cost effective. There was limited discussion of the ethics of screening, including the possible harms of screening in the absence of linkage to care. The gap between conducting good screening program and the appropriate follow-up with diagnosis and treatment remains one of the major challenges of screening in SSA.

DISCUSSION

There is insufficient real-world data to support the systematic implementation of national breast cancer screening in SSA. Further research is needed to answer important questions about screening, and national and international partnerships are needed to ensure that appropriate diagnostic and treatment modalities are available to patients who screen positive.

Trends in public sector radiological usage in the Western Cape Province, South Africa: 2009-2019

Background

Although global use of medical imaging has increased significantly, little is known about utilisation trends in low- and middle-income countries (LMICs).

Objectives

To evaluate changes over a decade in public sector diagnostic imaging utilisation at provincial level in a middle-income country.

Method

A retrospective analysis of medical imaging utilisation in the Western Cape Province of South Africa in 2009 and 2019. Use of conventional radiography, ultrasonography (US), fluoroscopy, CT, MRI, digital subtraction angiography (DSA) and whole-body digital radiography was assessed by total studies and studies/10³ people, for the whole province, the rural and metropolitan areas. Mammography utilisation was calculated for every 10³ females aged 40–70 years.

Results

The provincial population and total imaging investigations increased by 25% and 32%, respectively, whilst studies/10³ people increased by 5.5% (256 vs 270/10³), with marked variation by modality. Provincial US, CT and MRI utilisation/10³ people increased by 111% (20 vs 43/10³), 78% (10 vs 18/10³) and 32% (1.9 vs 2.5/10³) respectively, whilst use of fluoroscopy (3.6 vs 3.7/10³) and mammography (14.2 vs 15.9/10³ women aged 40–70 years) was steady and plain radiography decreased by 20% (216 vs 196/10³). For CT, mammography and fluoroscopy, percentage utilisation increases/10³ people were higher in the rural than metropolitan areas.

Conclusion

Population growth is the main driver of overall imaging utilisation in our setting. The relatively constant imaging workload per 1000 people, albeit with increasing ultrasound, CT and MR utilisation, and decreasing use of plain radiography, reflects improved provincial imaging infrastructure, and appropriate use of available resources.

Breast imaging at Chris Hani Baragwanath Academic Hospital: A clinically relevant audit

Background

Breast cancer is a major cause of morbidity and mortality worldwide. From experience, we have found that the disease burden at Chris Hani Baragwanath Academic Hospital (CHBAH) is unique with an advanced stage at presentation.

Objective

To perform a breast-imaging audit at CHBAH, focused on interpretive performance and disease burden.

Method

Demographic and imaging data were retrospectively collected over a 6-month period. Data collected and derived followed the audit-definitions and rules described within the American College of Radiology–breast-imaging reporting and data system (ACR–BI-RADS) atlas (5th edn.). A comparison was made to benchmark values published by the Radiological Society of North America (RSNA).

Results

A total of 1549 mammography examinations were analysed. The screening subgroup (n = 808) revealed 11 cancers with a cancer detection rate (CDR) of 13.6 per 1000 studies and a recall rate of 5.94. The diagnostic subgroup (n = 741) revealed 130 cancers with a CDR of 175.4 and an abnormal interpretation rate (AIR) of 39 per 100 studies. Along with the positive predictive values, these performance measures for diagnostic mammography were significantly larger than the RSNA-benchmarks (p < 0.0001). In addition, the cancer characteristics showed a greater histological mean tumour length, a lower percentage of minimal cancers (defined as ductal carcinoma in situ [DCIS] and invasive cancers ≤ 1 cm) and fewer nodal-negative cancers (p < 0.0001), in keeping with a more advanced loco-regional stage at presentation.

Conclusion

The study illustrates the challenges faced by a South African breast-imaging unit confronted with advanced loco-regional disease. The cancer burden is highlighted within a community where there is a lack of national screening mammography. The process of performing a basic, clinically relevant audit is simple and should be a routine practice in breast-imaging units.

Prevalence and determinants of breast cancer screening in four sub-Saharan African countries: a population-based study

OBJECTIVES

Breast cancer is the most prevalent cancer and the second leading cause of cancer-related deaths among women after cervical cancer in much of sub-Saharan Africa. This study aims to examine the prevalence and sociodemographic-socioeconomic factors associated with breast cancer screening among women of reproductive age in sub-Saharan Africa.

DESIGN

A weighted population-based cross-sectional study using Demographic and Health Surveys (DHS) data. We used all available data on breast cancer screening from the DHS for four sub-Saharan African countries (Burkina Faso, Ivory Coast, Kenya and Namibia). Breast cancer screening was the outcome of interest for this study. Multivariable Poisson regression was used to identify independent factors associated with breast cancer screening.

SETTING

Four countries participating in the DHS from 2010 to 2014 with data on breast cancer screening.

PARTICIPANTS

Women of reproductive age 15-49 years (N=39 646).

RESULTS

The overall prevalence of breast cancer screening was only 12.9% during the study period, ranging from 5.2% in Ivory Coast to 23.1% in Namibia. Factors associated with breast cancer screening were secondary/higher education with adjusted prevalence ratio (adjusted PR)=2.33 (95% CI: 2.05 to 2.66) compared with no education; older participants, 35-49 years (adjusted PR=1.73, 95% CI : 1.56 to 1.91) compared with younger participants 15-24 years; health insurance coverage (adjusted PR=1.57, 95% CI: 1.47 to 1.68) compared with those with no health insurance and highest socioeconomic status (adjusted PR=1.33, 95% CI : 1.19 to 1.49) compared with lowest socioeconomic status.

CONCLUSION

Despite high breast cancer mortality rates in sub-Saharan Africa, the prevalence of breast cancer screening is substantially low and varies gradually across countries and in relation to factors such as education, age, health insurance coverage and household wealth index level. These results highlight the need for increased efforts to improve the uptake of breast cancer screening in sub-Saharan Africa.