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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 5, September/October 2020
AFRICA
265
is higher in prepubertal girls, and this could be explained by the
lack of protection from female hormones. Further studies are
needed to understand in more detail the mechanism of female
protection.
Black race was found to be a risk factor for developing
ATRCD in both childhood cancer survivors
22
and adult
cancer patients.
23
In an
in vitro
study, Huang
et al
.
24
used
EBV-transformed B-lymphoblastoid HapMap cell lines derived
from an African- and a European-descent cell line, in order
to evaluate population- and gender-specific differences in cell
cardiotoxicity after daunorubicin and other drug (carboplatin,
cisplatin, etoposide) treatment. Interestingly, African-descent
cell lines were found to be more prone to develop cytotoxicity
linked to daunorubicin.
In Africa, two published studies done in Cote d’Ivoire
and Morocco reported a high incidence of cardiotoxicity in
adult cancer patients on anthracycline treatment. Elalouani
et al.
who conducted the first prospective cohort study in
Morocco, investigating the frequency of anthracycline-induced
cardiotoxicity, noted that 56% of the 70 patients developed a
decrease in cardiac function and 4% of cases developed severe
cardiotoxicity.
25
In the prospective cohort study performed
at Abidjan Institute of Cardiology over 10 months, 45 adult
patients were followed up and four patients (8.8%) developed
significant cardiotoxicity.
26
Cardiovascular care in African cancer patients:
current status, challenges and opportunities
Despite an increased risk of developing asymptomatic subclinical
ATRCD in Africa, there is a noted paucity of information
on burden of subclinical anthracycline-induced cardiotoxicity
and related predictors among adult cancer patients receiving
anthracycline chemotherapy. This large gap in knowledge has
led to a lack of local guidelines for monitoring and management
of ATRCD.
The majority of patients receive only screening
echocardiography before chemotherapy with no follow-up
cardiac screening. This may leave many anthracycline-treated
patients with undetected stage B heart failure (asymptomatic
subclinical cardiac dysfunction) at risk of developing stage C or
D heart failure when they encounter another cardiovascular risk
later in life.
Strain echocardiography (GLS) and biomarkers (troponin)
are verified diagnostic tools for this stage B heart failure. GLS
is becoming routinely used in this population in the developed
world but not in Africa, for a number of reasons. Indeed, many
cardiologists are not trained to use this methodology, and few
patients can afford the cost of serial echocardiography studies.
When strain echocardiography is not available, conventional
echocardiography parameters, which measure the longitudinal
motion of the left ventricle [mitral annular plane systolic
exertion (MAPSE), peak systolic mitral annular velocity by
tissue Doppler (S
′
)], may potentially be useful in Africa.
27
However, their roles in detecting subclinical ATRCD have not
been studied.
Compared to strain echocardiography, biomarker tests are
cheaper and less skill-dependent, therefore more practical in
African settings. Troponin, a biomarker of cardiac injury, has
been found to have high negative predictive value in detecting
subclinical ATRCD.
28
Natriuretic peptides, biomarkers of
cardiac load, are the next most commonly researched biomarkers
in the context of ATRCD, apart from troponin. However, their
roles in detecting subclinical ATRCD are less defined due to
conflicting results from different trials. Myeloperoxidase is
regarded as a marker of oxidative stress. In a recent study of
multiple biomarkers, myeloperoxidase levels rose early, persisted
throughout the course of therapy, and were associated with
cardiotoxicity.
29
Despite the challenges of implementing internationally
recommended cardiac care protocols for cancer patients in
SSA, conventional echocardiography combined with biomarker
tests may be potentially useful for African patients. These
tools have not been studied in SSA populations. Detecting
subclinical ATRCD in a low-income country (SATRACD
study) is an ongoing observational cohort study that will
diagnose subclinical ATRCD in Ugandan cancer patients using
international guidelines. The primary goal of this study is to
determine the burden and risk factors of subclinical ATRCD
in the study population, evaluating the role of conventional
echocardiography parameters and biomarkers in detecting
subclinical ATRCD in Ugandan cancer patients.
Conclusion
Due to the growing prevalence and unique pattern of cancer
populations in Africa and progress in oncology treatments,
there is increasing exposure of cancer patients to anthracycline.
Subclinical ATRCD is a silent risk factor for heart failure in
cancer survivors. Therefore subclinical ATRCD should no longer
be ignored in Africa.
Oncologists and cardiologists in Africa have a responsibility
to provide standard of care for patients receiving anthracycline
therapy by implementing international guidelines. Local research
in this field is needed to evaluate the real burden and risk factors
of anthracycline therapy-related stage B heart failure. Moreover,
in order to promote the application of available resources in
cardio-oncology clinical practice and help to establish national
guidelines for cardiac monitoring and management of patients
with ATRCD, research should investigate more easily accessible
tools to diagnose early damage, such as biomarkers and
conventional echocardiography parameters.
We appreciate the funding from the Medical Research Council of South Africa.
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