DISEASE-SPECIFIC CANCER CONTROL
98 CANCER CONTROL 2015
region (3, 4). To place these figures in context, according to
Globocan data for The Gambia, HCC accounts for more than
half of all cancer in men (176 of 292 cases per year in 2012)
and 62 of 265 cases per year among women in 2012. In
comparison cervical cancer, another cancer associated with
viral infection, accounted for an estimated 98 of the 265
reported cases in 2012, whilst breast cancer accounted for an
estimated 40 cases (5). Aflatoxin is a powerful mycotoxin;
exposure through Aspergillus flavus-contaminated groundnut
consumption in many regions of SSA works synergistically
with HBV infection to increase cancer risk (6, 7).
Unfortunately, the natural history of HCC usually follows a
highly aggressive course and limited treatment options are
available, particularly in resource-poor settings such as SSA
(8). Furthermore, HBV-related HCC affects African patients
in their working and reproductive years (8), maximising the
negative socioeconomic effects of this disease. HBV
therefore represents a critical threat to health in the African
continent.
Early detection and treatment of HBV infection reduces
HCC incidence and mortality (primary prevention) (9, 10).
Furthermore, HCC survival is improved by early detection of
potentially treatable HCC by screening of at-risk patients
(secondary prevention) (11). However, limited access to
affordable medical care is a major limiting factor in hepatitis
and liver cancer management in SSA. Routine HBV and HCC
screening and surveillance programmes for the general
population are virtually non-existent in SSA and there is a
lack of infrastructure to support channelling of screened
patients into long-term treatment programmes
(http://www.who.int/csr/disease/hepatitis/global_report/en/;
accessed 21 November 2014). Safe and effective treatments
for HBV exist, but treatment access is severely limited in SSA
due to cost. Despite highly effective nucleoside analogues
such as tenofovir being available in most countries in SSA, at
no cost through the Global Fund, or at generic price for the
treatment of HIV, very few African countries offer publiclyfunded
HBV treatment (http://www.who.int/csr/disease/
hepatitis/global_report/en/; accessed 21 November 2014).
Treatment options for HCC are severely limited in SSA,
with percutaneous ethanol injection being the only modality
available at a small number of centres. Furthermore, this
modality is only effective for early stage HCC (8) and
limitations in access to screening and diagnostic services in
SSA mean most HCC cases are diagnosed when they are
already at an advanced stage and no longer amenable to
therapy.
Vaccination is the cornerstone of HBV prevention and is
most effective when given within 24 hours of birth (12, 13).
Multiple studies from SSA have demonstrated that HBV
vaccination of infants is both feasible and highly effective for
preventing chronic HBV carriage (14-16). Despite WHO
guidelines recommending HBV vaccination be commenced
within 24 hours of birth, the vaccine schedule of 6, 10 and 14
weeks has been adopted in most African countries to allow
the use of combination vaccines and to minimise costs and
logistic expenses by streamlining vaccination schedules (17).
There is limited data on the relative effectiveness of this
approach compared to birth dose vaccination in sub-Saharan
Africa. Data from The Gambia Expanded Programme on
Immunization, where complete delivery of the intended
intervention of birth dose vaccination was not always
achieved due to logistical constraints, suggested efficacy of
95% in preventing chronic HBV infection overall (18, 19).
However, the number of women in these studies who were
HBeAg positive with high viral load was small and vaccine
failure appeared much higher in this group (18).
Furthermore, in Africa there is incomplete HBV vaccine
coverage, widely ranging from 10% in Chad to 99% in The
Gambia, with the average less than 70% for Africa as a
whole) (20, 21) (http://www.who.int/csr/disease/hepatitis/
global_report/en/; accessed 21 Nov 2014; http://www.
afro.who.int/; accessed 21 November 2014).
Control of HBV prevalence is a major goal for the World
Health Organization (WHO) worldwide, with a key focus on
HBV prevention in African countries. In 2010, the World
Health Assembly (WHA) passed a resolution calling for
public health intervention to prevent and control viral
hepatitis. There is also a forthcoming WHA resolution
requesting the Global Health Fund to provide antiviral
medications for HBV mono-infected patients. However, until
greater global action for equitable treatment access is
achieved, there remains a significant burden from HBVrelated
liver disease and HCC in SSA, with little access to
life-saving screening and treatment. Importantly, there is a
significant lack of Africa-specific guidelines for HBV and
HCC screening and treatment.
Prevention of hepatitis B-related liver fibrosis and
cancer in Africa: The PROLIFICA study
Against the sombre backdrop of HBV-related liver disease in
SSA described above, the Prevention of Liver Fibrosis and
Cancer in Africa (PROLIFICA) project was established in
2011 to address some of the urgent HBV research needs in
three West African countries: Senegal, The Gambia and
Nigeria. This is an on-going five-year translational research
project funded by the European Union Framework 7
(www.prolifica.eu; EU-FP7 #265994) and represents a