Post-malarial neurological syndrome in a Gambian adult residing in the Gambia: a case report and a review of literature.

BACKGROUND: Post malarial neurological syndrome (PMNS) occurs as a sequel of cerebral malaria which is the most deadly form of severe malaria. In holo-endemic regions (areas of high malarial transmission) all forms of severe malaria as well as cerebral malaria usually occur in children and those who are semi or non-immune like pregnant women, migrants as well as tourists. It also occurs in hypo-endemic regions (areas of limited malarial transmission with low immunity) and malaria- free zones. Survivors however may have neurologic complications after recovery. PMNS has been reported in many parts of the world. Being a sequel to cerebral malaria, it is uncommon in adults who were born and reside in a holo-endemic region all their lives. CASE REPORT: This is the case of an 18 year old Gambian who has lived in The Gambia all his life that had PMNS five days after recovery from cerebral malaria. METHODS: This was a predominantly web based literature search. The search comprise all case reports, original articles and reviews on PMNS or neurological deficits associated with malaria or noted after malaria infection. The search engines used were Google, Yahoo and Google scholar. RESULTS: A total of 62 papers were found. These were used for this review of the literature. CONCLUSION: Cerebral malaria also occurs in adults in holo-endemic areas though rare and some of the survivors may develop PMNS. It is commoner in the youth age group. There is need for further studies since the youth may be a possible new 'vulnerable group' in holoendemic areas. This may lead to the widening the targeted group for malaria control in the regions of high malarial transmission.

20-years of population-based cancer registration in hepatitis B and liver cancer prevention in the Gambia, West Africa.

BACKGROUND: The Gambia Hepatitis Intervention Study (GHIS) was designed as a randomised control trial of infant hepatitis B vaccination applied to public health policy, with the main goal of preventing primary liver cancer later in adult life in The Gambia. To that effect, the National Cancer Registry of The Gambia (NCR), a population-based cancer registry (PBCR), was established in 1986 to actively collect data on all cancer diagnosis nation-wide. We extracted 20-years (1990-2009) of data to assess for the first time, the evolution of the most common cancers, also describe and demonstrate the role of the PBCR in a hepatitis B and liver cancer prevention programme in this population. METHODS AND FINDINGS: We estimated Age-Standardised Incidence Rates (ASR (W)) of the most common cancers registered during the period by gender. The registration period was divided into four 5-year intervals and incidence rates were estimated for each interval. The most common cancers in males were liver, prostate, lung plus bronchus, non-Hodgkin lymphoma (NHL) and stomach, accounting for 60%, 5%, 4%, 5% and 3%, respectively. Similarly, cancers of the cervix uteri, liver, breast and NHL, were the most common in females, accounting for 33%, 24%, 11% and 4% of the female cancers, respectively. CONCLUSIONS: Cancer incidence has remained relatively stable over time, but as shown elsewhere in sub-Saharan Africa the disease is a threat in The Gambia. The infection related cancers which are mostly preventable (HBV in men and HPV/HIV in women) were the most common. At the moment the data is not enough to detect an effect of hepatitis B vaccination on liver cancer incidence in The Gambia. However, we observed that monitoring case occurrence through PBCR is a key public health pre-requisite for rational planning and implementation of targeted interventions for improving the health of the population.

Breast cancer in pre-menopausal women in West Africa: analysis of temporal trends and evaluation of risk factors associated with reproductive life.

BACKGROUND: In West Africa, trends and risk factors for breast cancer (BC) have been rarely studied. METHODS: Here we have analyzed trends of BC over two periods in two population-based cancer registries, in Mali-Bamako (1987-1997; 1998-2009) and in The Gambia (1988-1997; 1998-2006). We have conducted a case-control study (n = 253 cases, 249 controls) on risk factors associated with reproductive life stratified by menopausal status in Bamako. RESULTS: Between the two periods, BC incidence rates increased by 20% (incidence rate ratio (IRR) 1.20 (95% CI [1.07-1.35])) in Bamako, with an annual percentage change of 2% (95% CI [0.4-3.6]). The increase was of 30% in women under 55 years (IRR 1.30 (95% CI [1.14-1.60])). A similar pattern was observed in The Gambia for women under 50 years (IRR 1.47 (95% CI [1.07-2.01])). Overall, pre-menopausal breast cancer was predominant in both countries. In contrary to what is well established, case-control study showed that late age at menarche (>14 years) increased the risk of BC among pre-menopausal women (OR: 2.02 (95% CI [1.08-3.78])) while it tended to be protective in post-menopausal women (OR: 0.61 (95% CI [0.29-1.29])). Later age at a first pregnancy (>20 years) was associated with a reduction of risk in pre-menopausal women (OR: 0.41 (95% CI [0.18-0.89])). CONCLUSION: These results indicate that the burden of pre-menopausal BC is increasing in West African countries. These cancers appear to be associated with distinct reproductive risk factors, highlighting the need for better understanding the biological bases of early BC in African populations.

Evaluation of data quality at the Gambia national cancer registry.

The Gambia National Cancer Registry (GNCR) is one of the few nationwide population-based cancer registries in sub-Saharan Africa. Most registries in sub-Saharan Africa are limited to cities; therefore, the GNCR is important in providing estimates of cancer incidence in rural Africa. Our study assesses the quality of its data. The methods proposed by Bray and Parkin, and Parkin and Bray (Eur J Cancer 2009;45:747-64) were applied to the registry data from 1990 to 2009 to assess comparability, validity and completeness. The system used for classification and coding of neoplasms followed international standards. The percentage of cases morphologically verified was 18.1% for men and 33.1% for women, and that of death certificate only cases was 6.6 and 3.6%, respectively. Incidence rates in rural regions were lower than in the urban part of the country, except amongst young male adults. Comparison with other West African registries showed that the incidences of liver and uterine cervical cancer were comparable, but those of prostate and breast in The Gambia were relatively low. The overall completeness was estimated at 50.3% using the capture-recapture method. The GNCR applies international standard practices to data collection and handling, providing valuable data on cancer incidence in sub-Saharan Africa. However, the data are incomplete in the rural and elderly populations probably because of health care access and use.

TP53 R249S mutation, genetic variations in HBX and risk of hepatocellular carcinoma in The Gambia.

In regions with high prevalence of chronic hepatitis B virus (HBV) infection and dietary aflatoxin B(1) (AFB(1)) exposure, hepatocellular carcinomas (HCCs) often contain TP53 mutation at codon 249 (R249S). Furthermore, a C-terminal truncated HBx protein expressed from hepatocyte integrated HBV is associated with HCC development. This study evaluates the association between R249S and HBX status in relation to HCC in West African population. HBX (complete or 3'-truncated) and HBS genes were assessed by PCR in cell-free DNA (CFDNA) from plasma of subjects recruited in a hospital-based case-control study (325 controls, 78 cirrhotic patients and 198 HCC cases) conducted in The Gambia. These samples had been previously analyzed for R249S and HBV serological status. Complete HBX sequence was frequently detected in CFDNA of HCC-R249S positive (77%, 43/56) compared with HCC-R249S-negative cases (44%, 22/50). Conversely, the proportion of 3'-truncated HBX gene was significantly higher in HCC-R249S negative than positive cases (34%, 17/50, compared with 12%, 7/56) (χ(2) = 12.12; P = 0.002; distribution of R249S negative and positive according to HBX status). Occult HBV infection (detected by PCR) was present in 24% of HCC previously considered as negative by HBV serology. Moreover, HBV mutation analysis revealed that double mutation at nucleotides 1762(T)/1764(A) was associated with diagnosis of cirrhosis or HCC {cirrhosis: odds ratio (OR): 9.50 [95% confidence interval (CI) 1.50-60.11]; HCC: OR: 11.29 [95% CI 2.07-61.47]}. These findings suggest that in HCC from The Gambia, complete HBX sequences are often associated with the presence of TP53 R249S mutation.

Seasonal variation in TP53 R249S-mutated serum DNA with aflatoxin exposure and hepatitis B virus infection.

BACKGROUND: Chronic hepatitis B virus (HBV) infection and dietary aflatoxin B1 (AFB1) exposure are etiological factors for hepatocellular carcinoma (HCC) in countries with hot, humid climates. HCC often harbors a TP53 (tumor protein p53) mutation at codon 249 (R249S). In chronic carriers, 1762T/1764A mutations in the HBV X gene are associated with increased HCC risk. Both mutations have been detected in circulating cell-free DNA (CFDNA) from asymptomatic HBV carriers. OBJECTIVE: We evaluated seasonal variation in R249S and HBV in relation to AFB1 exposure. METHODS: R249S was quantitated by mass spectrometry in CFDNA in a cross-sectional survey of 473 asymptomatic subjects (237 HBV carriers and 236 noncarriers) recruited in three villages in the Gambia over a 10-month period. 1762T/1764A HBV mutations were detected by quantitative polymerase chain reaction. In addition, the HBV S gene was sequenced in 99 subjects positive for HBV surface antigen (HBsAg). RESULTS: We observed a seasonal variation of serum R249S levels. Positivity for R249S and average concentration were significantly higher in HBsAg-positive subjects surveyed during April-July (61%; 5,690 ± 11,300 R249S copies/mL serum) than in those surveyed October-March [32% and 480 ± 1,030 copies/mL serum (odds ratio = 3.59; 95% confidence interval: 2.05, 6.30; p < 0.001)]. Positivity for HBV e antigen (HBeAg) (a marker of HBV replication) and viral DNA load also varied seasonally, with 15-30% of subjects surveyed between April and June HBeAg positive, compared with < 10% surveyed during other months. We detected 1762T/1764A mutations in 8% of carriers, half of whom were positive for R249S. We found HBV genotype E in 95 of 99 HBsAg-positive subjects. CONCLUSION: R249S is detectable in CFDNA of asymptomatic subjects. Evidence of temporal and quantitative variations suggests an interaction among AFB1 exposure, HBV positivity, and replication on TP53 mutation formation or persistence.

Increase in female liver cancer in the Gambia, West Africa: evidence from 19 years of population-based cancer registration (1988-2006).

BACKGROUND: Hepatocellular carcinoma (HCC) is a common malignancy worldwide with a high burden in West Africa. Male to female ratios show consistent bias toward males, the biological bases and variations of which are not well understood. We have used data from the Gambian National Cancer Registry to compare trends in incidence of HCC in both genders. METHODS AND FINDINGS: Two periods were compared, 1988-1997 (early) and 1998-2006 (recent). In addition, the regression program joinpoint was used to assess trends over 19 years. Differences with self-reported ethnicity were assessed for the recent period using population data from 2003 census. Male to female ratio showed a significant decrease between the two periods from 3.28∶1 (95% CI, [2.93-3.65]) to 2.2∶1 (95% CI, [1.99-2.43]). Although rates in males were relatively stable (38.36 and 32.84 for, respectively, early and recent periods), they increased from 11.71 to 14.9 in females with a significant Annual Percentage Change of 3.01 [0.3-5.8] over 19 years and an increase in number of cases of 80.28% (compared to 26% in males). Significant variations in HCC risk, but not in gender ratio were observed in relation with ethnicity. CONCLUSION: This analysis of the only national, population-based cancer registry in West Africa shows a significant increase in HCC in females over recent years. This increase may be the consequence of major changes in lifestyle or viral risk factors, in particular obesity and hepatitis C, which have both been documented to increase in West Africa during recent years.

Aetiological differences in demographical, clinical and pathological characteristics of hepatocellular carcinoma in The Gambia.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, with a high burden in West Africa. Data evaluating aetiological differences in HCC presentation from this region are limited. AIMS: The aim of this study was to describe the demographical, clinical and pathological characteristics of HCC by aetiology (hepatitis B or C infection, aflatoxin associated). METHODS: One hundred and ninty-three cases of HCC diagnosed between 1997 and 2001 in The Gambia were analysed. Characteristics were compared by aetiology using χ(2)-tests, student t-test and Wilcoxon's rank sum tests as appropriate. RESULTS: The prevalence of hepatitis B surface antigen, hepatitis C antibody and aflatoxin-associated 249(ser) TP53 mutations among HCC patients was 60, 20 and 38% respectively. The typical HCC patient was a 49-year-old male positive for hepatitis B surface antigen presenting with hepatomegaly (93%), abdominal pain (94%) and weight loss (95%) 8 weeks after symptom onset. Most patients had multifocal lesions with background cirrhosis. The median largest tumour was 10.3 cm and the median α-fetoprotein level was 500 ng/ml. Eighty-four per cent of patients had advanced HCC (patients not meeting the Milan criteria) at presentation. CONCLUSIONS: Irrespective of aetiological agent, HCC among West Africans presents at very advanced stages. Few clinical or pathological differences exist by aetiology. More studies are needed to understand the mechanisms of hepatocarcinogenesis among these patients as well as identify high-risk populations in which early detection through screening will be beneficial.

Population-based breast (female) and cervix cancer rates in the Gambia: evidence of ethnicity-related variations.

Since 1987, the Gambia National Cancer Registry has provided nationwide cancer registration for the Gambia. We used data from 1998 to 2006 to assess age-standardized incidence rates (ASRs) of 2 common cancers in women, breast and cervix. With an ASR of 15.42 (95% CI [14.18-16.66]) for cervix and 5.86 (95% CI [5.12-6.59]) for breast per 10(5) person-years, these cancers ranked first and third, respectively, among Gambian women (the second most common being liver, ASR 14.90). Incidence of both cancers, breast and cervix, increased rapidly at young ages to reach a peak at ages 40-44 years. Significant differences were observed in relation to ethnicity. Using the Mandinka (42% of the population) as a reference, breast cancer incidence rates were 2.16-fold higher (95% CI [1.33-3.52]) in Jola (10% of the population), specially at early-onset ages (before 40 years). For cervix cancer, highest rates were observed in Fula (18% of the population; risk ratio (RR): 1.84 (95% CI [1.44-2.36])). In contrast, a significantly lower risk was observed in the Serrahuleh (9% of the population; RR: 0.54 (95% CI [0.31-0.96]). This study revealed a preponderance of early-onset breast cancer among Gambian women similar to that seen in African women in more developed countries but also demonstrates large ethnic variations. It points to the need for further studies on cancer determinants to improve prevention, early detection and therapeutic management of these diseases in a low-resource setting in West Africa.

Cancer survival in Africa, Asia, and Central America: a population-based study.

BACKGROUND: Population-based cancer survival data, a key indicator for monitoring progress against cancer, are not widely available from countries in Africa, Asia, and Central America. The aim of this study is to describe and discuss cancer survival in these regions. METHODS: Survival analysis was done for 341 658 patients diagnosed with various cancers from 1990 to 2001 and followed up to 2003, from 25 population-based cancer registries in 12 countries in sub-Saharan Africa (The Gambia, Uganda), Central America (Costa Rica), and Asia (China, India, Pakistan, Philippines, Saudi Arabia, Singapore, South Korea, Thailand, Turkey). 5-year age-standardised relative survival (ASRS) and observed survival by clinical extent of disease were determined. FINDINGS: For cancers in which prognosis depends on stage at diagnosis, survival was highest in China, South Korea, Singapore, and Turkey and lowest in Uganda and The Gambia. 5-year ASRS ranged from 76-82% for breast cancer, 63-79% for cervical cancer, 71-78% for bladder cancer, and 44-60% for large-bowel cancers in China, Singapore, South Korea, and Turkey. Survival did not exceed 22% for any cancer site in The Gambia; in Uganda, survival did not exceed 13% for any cancer site except breast (46%). Variations in survival correlated with early detection initiatives and level of development of health services. INTERPRETATION: The wide variation in cancer survival between regions emphasises the need for urgent investments in improving awareness, population-based cancer registration, early detection programmes, health-services infrastructure, and human resources. FUNDING: Association for International Cancer Research (AICR; St Andrews, UK), Association pour la Recherche sur le Cancer (ARC, Villejuif, France), and the Bill & Melinda Gates Foundation (Seattle, USA).

International collaborations in cancer control and the Third International Cancer Control Congress.

Over the past few decades, there has been growing support for the idea that cancer needs an interdisciplinary approach. Therefore, the international cancer community has developed several strategies as outlined in the WHO non-communicable diseases Action Plan (which includes cancer control) as the World Health Assembly and the UICC World Cancer Declaration, which both include primary prevention, early diagnosis, treatment, and palliative care. This paper highlights experiences/ideas in cancer control for international collaborations between low, middle, and high income countries, including collaborations between the European Union (EU) and African Union (AU) Member States, the Latin-American and Caribbean countries, and the Eastern Mediterranean countries. These proposals are presented within the context of the global vision on cancer control set forth by WHO in partnership with the International Union Against Cancer (UICC), in addition to issues that should be considered for collaborations at the global level: cancer survival (similar to the project CONCORD), cancer control for youth and adaptation of Clinical Practice Guidelines. Since cancer control is given lower priority on the health agenda of low and middle income countries and is less represented in global health efforts in those countries, EU and AU cancer stakeholders are working to put cancer control on the agenda of the EU-AU treaty for collaborations, and are proposing to consider palliative care, population-based cancer registration, and training and education focusing on primary prevention as core tools. A Community of Practice, such as the Third International Cancer Control Congress (ICCC-3), is an ideal place to share new proposals, learn from other experiences, and formulate new ideas. The aim of the ICCC-3 is to foster new international collaborations to promote cancer control actions in low and middle income countries. The development of supranational collaborations has been hindered by the fact that cancer control is not part of the objectives of the Millennium Development Goals (MGGs). As a consequence, less resources of development aids are allocated to control NCDs including cancer.

Aflatoxin exposure and viral hepatitis in the etiology of liver cirrhosis in the Gambia, West Africa.

BACKGROUND: Cirrhosis of the liver is thought to be a major cause of morbidity and mortality in sub-Saharan Africa, but few controlled studies on the etiology of cirrhosis have been conducted in this region. OBJECTIVES: We aimed to elucidate the association between environmental and infectious exposures and cirrhosis in The Gambia. METHODS: Ninety-seven individuals were diagnosed with cirrhosis using a validated ultrasound scoring system and were compared with 397 controls. Participants reported demographic and food frequency information. Blood samples were tested for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis C virus (HCV) antibody, HCV RNA, and the aflatoxin-associated 249(ser) TP53 mutation. RESULTS: HBsAg seropositivity was associated with a significant increase in risk of cirrhosis [odds ratio (OR) = 8.0; 95% confidence interval (CI), 4.4-14.7] as was the presence of HBeAg (OR = 10.3; 95% CI, 2.0-53.9) and HCV infection (OR = 3.3; 95% CI, 1.2-9.5). We present novel data that exposure to aflatoxin, as assessed both by high lifetime groundnut (peanut) intake and by the presence of the 249(ser) TP53 mutation in plasma, is associated with a significant increase in the risk for cirrhosis (OR = 2.8; 95% CI, 1.1-7.7 and OR = 3.8; 95% CI, 1.5-9.6, respectively). Additionally, aflatoxin and hepatitis B virus exposure appeared to interact synergistically to substantially increase the risk of cirrhosis, although this was not statistically significant. CONCLUSIONS: Our results suggest that the spectrum of morbidity associated with aflatoxin exposure could include cirrhosis.

20 years into the Gambia Hepatitis Intervention Study: assessment of initial hypotheses and prospects for evaluation of protective effectiveness against liver cancer.

Primary hepatocellular carcinoma is the commonest cancer in The Gambia. The Gambia Hepatitis Intervention Study (GHIS) was established in 1986 to evaluate the protective effectiveness of infant hepatitis B immunization in the prevention of chronic liver disease, particularly, hepatocellular carcinoma and cirrhosis later in adult life. This program was designed based on a series of assumptions. Here, we used data from observational and epidemiologic studies developed since 1986 to examine the validity of these assumptions. We found that (a) hepatitis B vaccine coverage was 15% more than originally assumed, (b) protection against hepatitis B virus (HBV) infection was not dependent on the number of vaccine doses received, (c) perinatal infection with HBV was of negligible importance, and (d) the HBV attributable risk of hepatocellular carcinoma at age < 50 was 70% to 80%, lower than initially assumed. Based on these data, the final outcome of the GHIS should be measurable from 2017, sooner than originally assumed. The GHIS strategy takes into account-specific patterns of virus epidemiology and natural history of hepatocellular carcinoma in Africa and provides a model for integrating and evaluating new vaccines into the Expanded Programme of Immunization of sub-Saharan African countries.

Long-term protection against HBV chronic carriage of Gambian adolescents vaccinated in infancy and immune response in HBV booster trial in adolescence.

BACKGROUND: Chronic infection with hepatitis B virus (HBV) arising in childhood is associated with hepatocellular carcinoma in adult life. Between 1986 and 1990, approximately 120,000 Gambian newborns were enrolled in a randomised controlled trial to assess the effectiveness of infant HBV vaccination on the prevention of hepatocellular carcinoma in adulthood. These children are now in adolescence and approaching adulthood, when the onset of sexual activity may challenge their hepatitis B immunity. Thus a booster dose in adolescence could be important to maintain long-term protection. METHODS: Fifteen years after the start of the HBV infant vaccination study, 492 vaccinated and 424 unvaccinated children were identified to determine vaccine efficacy against infection and carriage in adolescence. At the same time, 297 of the 492 infant-vaccinated subjects were randomly offered a booster dose of HBV vaccine. Anti-HBs was measured before the booster, and two weeks and 1 year afterwards (ISRCTN71271385). RESULTS: Vaccine efficacy 15 years after vaccination was 67.0% against infection as manifest by anti-HBc positivity (95% CI 58.2-74.6%), and 96.6% against HBsAg carriage (95% CI 91.5-100%). 31.2% of participants had detectable anti-HBs with a GMC of 32 IU/l. For 168 boosted participants GMC anti-HBs responses were 38 IU/l prior to vaccination, 524 IU/l two weeks after boosting, and 101 IU/l after 1 year. CONCLUSIONS: HBV vaccination in infants confers very good protection against carriage up to 15 years of age, although a large proportion of vaccinated subjects did not have detectable anti-HBs at this age. The response to boosting persisted for at least a year. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN71271385.

Molecular epidemiology of human liver cancer: insights into etiology, pathogenesis and prevention from The Gambia, West Africa.

Human liver cancer, primarily hepatocellular carcinoma (HCC), is both common and lethal. Notable variation in HCC incidence rates worldwide corresponds to the prevalence and pattern of the primary etiologic factors. In summary of decades of collaborative research centered in The Gambia, West Africa, this review explores the independent and combined effects of hepatitis B virus (HBV), hepatitis C virus (HCV) and dietary aflatoxin exposure in the etiology of HCC. Through population surveys, field trials and a series of HCC case-control studies, the patterns and natural history of HBV, HCV and aflatoxin exposures have been defined within this population. These investigations have paralleled and informed the development of molecular biomarkers of these etiologic agents and contributed to understanding the complex mechanisms involved in hepatocarcinogenesis. We discuss preventive approaches to reduce the global burden of HCC, emphasizing The Gambia Hepatitis Intervention Study, a countrywide randomized controlled trial designed to document the efficacy of HB vaccination in preventing HBV infections and HBV-related HCC. By recognizing the synergy of applying molecular techniques to population-based epidemiological studies, the portfolio of Gambian research projects presented provides a model for partnering etiologic and mechanistic investigations with applied research.