The pattern of pediatric solid malignant tumors in western Kenya, east Africa, 1979-1994: an analysis based on histopathologic study

Mapping evidence on the risk factors associated with pediatric cancers in sub-Saharan Africa: a scoping review

BACKGROUND

The rarity and heterogeneity of pediatric cancers make it difficult to assess risk factors associated with the development of cancer in this group. This also determines the quantity and quality of evidence for etiological factors linked to pediatric cancers. Evidence on the risk factors associated with pediatric cancers is scarce; however, it has been accumulating slowly over the years. As the disease burden shifts from communicable to non-communicable diseases, most of these low- to middle-income countries (LMICs) find themselves overburdened with changing health care priorities and needs. In sub-Saharan Africa, it is of major importance to pay particular attention to risk factors associated with pediatric cancer.

OBJECTIVE

To map evidence on risk factors associated with pediatric cancers in sub-Saharan Africa (SSA).

METHODS

This review was guided by Arksey and O'Malley's framework for conducting scoping reviews. Four electronic databases were searched in December 2018, and another manual search was conducted in February 2022 to include newly published eligible articles. The databases searched included PubMed and Health Source: Nursing/Academic Edition. We also searched articles from an academic search engine, Google scholar. This review included articles reporting the relevant outcomes of this study and articles reporting cancers in children in the 0-15 years age range. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews (PRISMA-ScR): checklist and explanation.

RESULTS

We retrieved 7391 articles from the initial database. The final number of studies that were included for data extraction was 15. Evidence from the retrieved studies suggests that most childhood cancers in the SSA region are infection-induced. The type of cancer mostly reported is Burkitt Lymphoma and is diagnosed mostly in the tropical region of SSA. The type of risk factors was divided into three types: infection-induced, genetic, and demographic risk factors. Overall, based on the articles retrieved, there was limited evidence on the risk factors associated with pediatric cancers in SSA.

CONCLUSION

The limited evidence on the risk factors coupled with the lack of evidence on the true burden of these malignancies in the SSA hampers efforts to set priorities for childhood cancer control. Formulation of effective preventative (where possible) measures and treatment regimens will need proper assessment of risk factors.

Epstein-Barr virus subverts mevalonate and fatty acid pathways to promote infected B-cell proliferation and survival

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with multiple human malignancies. EBV drives B-cell proliferation, which contributes to the pathogenesis of multiple lymphomas. Yet, knowledge of how EBV subverts host biosynthetic pathways to transform resting lymphocytes into activated lymphoblasts remains incomplete. Using a temporal proteomic dataset of EBV primary human B-cell infection, we identified that cholesterol and fatty acid biosynthetic pathways were amongst the most highly EBV induced. Epstein-Barr nuclear antigen 2 (EBNA2), sterol response element binding protein (SREBP) and MYC each had important roles in cholesterol and fatty acid pathway induction. Unexpectedly, HMG-CoA reductase inhibitor chemical epistasis experiments revealed that mevalonate pathway production of geranylgeranyl pyrophosphate (GGPP), rather than cholesterol, was necessary for EBV-driven B-cell outgrowth, perhaps because EBV upregulated the low-density lipoprotein receptor in newly infected cells for cholesterol uptake. Chemical and CRISPR genetic analyses highlighted downstream GGPP roles in EBV-infected cell small G protein Rab activation. Rab13 was highly EBV-induced in an EBNA3-dependent manner and served as a chaperone critical for latent membrane protein (LMP) 1 and 2A trafficking and target gene activation in newly infected and in lymphoblastoid B-cells. Collectively, these studies identify highlight multiple potential therapeutic targets for prevention of EBV-transformed B-cell growth and survival.

EBV, the first human tumor virus identified, persistently infects >95% of adults worldwide. Upon infection of small, resting B-lymphocytes, EBV establishes a state of viral latency, where viral oncoproteins and non-coding RNAs activate host pathways to promote rapid B-cell proliferation. EBV’s growth-transforming properties are closely linked to the pathogenesis of multiple immunoblastic lymphomas, particularly in immunosuppressed hosts. While EBV oncogenes important for B-cell transformation have been identified, knowledge remains incomplete of how these EBV factors remodel cellular metabolism, a hallmark of human cancers. Using a recently established proteomic map of EBV-mediated B-cell growth transformation, we found that EBV induces biosynthetic pathways that convert acetyl-coenzyme A (acetyl-CoA) into isoprenoids, steroids, terpenoids, cholesterol, and long-chain fatty acids. Viral nuclear antigens cooperated with EBV-activated host transcription factors to upregulate rate-limiting enzymes of these biosynthetic pathways. The isoprenoid geranylgeranyl pyrophosphate was identified as a key product of the EBV-induced mevalonate pathway. Our studies highlighted GGPP roles in Rab protein activation, and Rab13 was identified as a highly EBV-upregulated GTPase critical for LMP1 and LMP2A trafficking and signaling. These studies identify multiple EBV-induced metabolic enzymes important for B-cell transformation, including potential therapeutic targets.

Epidemiological review of childhood cancers in central Sudan

Background: Epidemiological studies of paediatric cancer incidence in Sudan are rare.Objectives: The aim of this study was to provide baseline information about the epidemiology of childhood cancers in patients treated at the National Cancer Institute (NCI) in Wad Medani, Sudan.Methods: We performed a retrospective health facility–based study of cancer incidence and patient characteristics of children who were treated at the NCI from January 1999 to December 2015. The changing patterns of cancers incidence during the study period were also recorded.Results: Of 15 387 new patients with cancer who were registered at the NCI during the study period, 1159 (7.5%) were children (younger than 15 years). The mean age of the paediatric patients was 7 years, with standard deviation of 5. Most of the patients (36%) were 10 to 15 years old, 33% were 0 to 4 years old and 31% were 5 to 10 years old. Among the study population, 60% were males and 40% were females. Approximately 76% of children lived in rural areas in Sudan. Leukaemias (29%) and lymphomas (26%) comprised 55% of all paediatric cancers. Central nervous system (CNS) tumours constituted 6% of all paediatric tumours, whereas non-CNS embryonal tumours (i.e. nephroblastoma, neuroblastoma, hepatoblastoma and retinoblastoma) accounted for 20%. The average number of cases per year increased from 42 in 1999–2005 to 75 in 2006–2010 and 106 in 2011–2015.Conclusion: The number of patients seeking treatment for childhood cancers has increased every year in central Sudan. Leukaemias and lymphomas constitute more than half of these cancers. A population-based cancer registry is needed to determine the true incidence of childhood cancers in Sudan.

Cancer of childhood in sub-Saharan Africa

Measurement of incidence rates of childhood cancer in Africa is difficult. The study 'Cancer of Childhood in sub Saharan Africa' brings together results from 16 population-based registries which, as members of the African Cancer Registry Network (AFCRN), have been evaluated as achieving adequate coverage of their target population. The cancers are classified according to the third revision of the International Classification of Childhood Cancer (ICCC-3) and recorded rates in Africa are compared with those in childhood populations in the UK, France, and the USA. It is clear that, in many centres, lack of adequate diagnostic and treatment facilities leads to under-diagnosis (and enumeration) of leukaemias and brain cancers. However, for several childhood cancers, incidence rates in Africa are higher than those in high-income countries. This applies to infection-related cancers such as Kaposi sarcoma, Burkitt lymphoma, Hodgkin lymphoma and hepatocellular carcinoma, and also to two common embryonal cancers - retinoblastoma and nephroblastoma. These (and other) observations are unlikely to be artefact, and are of considerable interest when considering possible aetiological factors, including ethnic differences in risk (and hence genetic/familial antecedents). The data reported are the most extensive so far available on the incidence of cancer in sub Saharan Africa, and clearly indicate the need for more resources to be devoted to cancer registration, especially in the childhood age range, as part of an overall programme to improve the availability of diagnosis and treatment of this group of cancers, many of which have-potentially-an excellent prognosis.

Pediatric solid tumors in Africa: different biology?

PURPOSE OF REVIEW

To review the recent literature regarding biologic characteristics of pediatric solid tumors in African children.

RECENT FINDINGS

Data regarding pediatric solid tumors in Africa, while increasing, remain sparse when considering the ethnic and geographic diversity of the continent. Recent work, especially regarding nephroblastoma in Kenya, has identified some biologic variability among local tribes but also when compared with North American tumors. In general, reports from across the continent reveal markedly poorer survival for pediatric patients with solid tumors when compared with high-resourced regions.

SUMMARY

Multiple resource-related and infrastructure-related challenges contribute to poorer outcomes, and these require systematic, multidisciplinary, and structured solutions. Socioeconomic factors and limited access to care currently seem to drive the survival outcomes in children with solid cancers in Africa.

Mapping the Epidemiology of Kaposi Sarcoma and Non-Hodgkin Lymphoma Among Children in Sub-Saharan Africa: A Review

Children with human immunodeficiency virus (HIV) have an increased risk of developing Kaposi Sarcoma (KS) and non-Hodgkin lymphoma (NHL) compared to HIV-negative children. We compiled currently published epidemiologic data on KS and NHL among children in sub-Saharan Africa (SSA). Among countries with available data, the median incidence of KS was 2.05/100,000 in the general pediatric population and 67.35/100,000 among HIV-infected children. The median incidence of NHL was 1.98/100,000 among the general pediatric population, while data on NHL incidence among HIV-infected children were lacking. Larger regional studies are needed to better address the dearth of epidemiologic information on pediatric KS and NHL in SSA.

Childhood cancer in Gondar University Hospital, Northwest Ethiopia

Background

Childhood cancer becomes a public health problem in developing countries which aggravates the burden of childhood mortality by infectious diseases and malnutrition. In poor countries, the death rate for most pediatric cancers is almost 100 %. This study attempts to determine the magnitude, patterns and trends of pediatric malignancies in the study area which is important in re-evaluating existing services and in improving facilities and patient care.

Methods

A retrospective study of 3 year period were carried out among all children aged below 15 years old admitted into the pediatric wards of Gondar University Hospital, Northwest Ethiopia. The charts of all children aged below 15 years old admitted in the pediatric wards due to cancer were reviewed by using the data collection format. Data were entered and analyzed using SPSS version 20 statistical package.

Result

A total of 71 cancer cases were diagnosed and admitted to the pediatrics ward during the study period. More than two-third of the study subjects 50 (70.4 %) were males. The mean age of study subjects was 7 ± 4 year where majority 26 (36.6 %) of the study subjects were ≥10 years. Of all, 43 (60.6 %) were hematological malignancy followed by Wilms tumor 13 (18.3 %), Neuroblastoma 5 (7 %), Rhabdomyosarcoma 3 (4.2 %), Brain tumor 3 (4.2 %), Hepatoblastoma 2 (2.8 %). More than two-third of cases were found to be concomitantly malnourished being stunted, wasted and under weight. Nearly half of patients had not received chemotherapy and majority of those started chemotherapy did not complete all the treatment cycles. Shortage and absence of safe and affordable chemotherapy drugs were the major reasons for therapy interruption.

Conclusion

The study shows increasing childhood cancer cases over the years. Hematological malignancy takes the leading prevalence followed by Wilms tumor and Neuroblastoma. The majority of cases were also discharged without any clinical change that had the only death option. Therefore, the government and the hospital should give emphasis to establish cancer therapy centers and insure accessibility and affordability of chemotherapy drugs.

Pattern of childhood cancer in University College Hospital, Ibadan during 1991-2010 and comparison with the previous three decades

BACKGROUND

Cancer is an important cause of morbidity and mortality worldwide in children under 15 years of age, with the incidence and mortality rate varying from 40 to 155 per million children.

AIM

To describe the pattern of childhood cancer in Ibadan, Nigeria.

OBJECTIVE

To compare the findings of this study with those of previous studies in Ibadan and internationally.

METHODS

A retrospective review of histologically and cytologically confirmed cases of cancer in children aged <15 years diagnosed at University College Hospital (UCH), Ibadan between January 1991 and December 2010 was undertaken. The cases were categorised using the International Classification of Childhood Cancer, third edition (ICCC-3).

RESULTS

There were 625 cases comprising 360 (57·6%) males with a modal age of 3 years. The most common neoplasms were lymphomas (140, 22·4%), of which 90% were non-Hodgkin lymphomas, with Burkitt lymphoma constituting the majority of cases (73). Other common neoplasms were retinoblastomas (21%), soft tissue sarcomas (14·9%), leukaemias (10·2%) and CNS tumours (6·9%). Lymphomas, bone tumours, malignant hepatic tumours and other malignant epithelial neoplasms had the highest mean and modal ages, while retinoblastomas, neuroblastomas, germ cell tumours and renal tumours had the lowest mean and modal ages. During 1960-72 there were 1326 cases and during 1973-90 there were 1881 cases and the proportion of lymphomas was 58·9% and 45·4%, respectively. The present study demonstrated a marked decline in the number of cases and proportion of lymphomas (22·4%), particularly Burkitt lymphomas.

CONCLUSION

During the last 20 years, there has been a decline in the number of cases of childhood cancer seen at UCH, Ibadan. This may be due to the establishment of additional specialist centres in the sub-region. Owing to a persistent decline in the frequency of Burkitt lymphoma, retinoblastoma is now the most common individual childhood cancer seen at Ibadan.

Cancer mortality pattern in lagos university teaching hospital, lagos, Nigeria

Background. Cancer is a leading cause of death worldwide and about 70% of all cancer deaths occurred in low- and middle-income countries. The cancer mortality pattern is quite different in Africa compared to other parts of the world. Extensive literature research showed little or no information about the overall deaths attributable to cancer in Nigeria. Aims and Objectives. This study aims at providing data on the patterns of cancer deaths in our center using the hospital and autopsy death registers. Methodology. Demographic, clinical data of patients who died of cancer were extracted from death registers in the wards and mortuary over a period of 14 years (2000–2013). Results. A total of 1436 (4.74%) cancer deaths out of 30287 deaths recorded during the period. The male to female ratio was 1 : 2.2 and the peak age of death was between 51 and 60 years. Overall, breast cancer was responsible for most of the deaths. Conclusion. The study shows that the cancers that accounted for majority of death occurred in organs that were accessible to screening procedures and not necessary for survival. We advise regular screening for precancerous lesions in these organs so as to reduce the mortality rate and burden of cancer.

Seasonality of Burkitt's lymphoma in Uganda

BACKGROUND/AIMS

Burkitt's lymphoma is the most common childhood oral maxillofacial tumor in Africa and some studies have reported seasonal variation.

MATERIALS AND METHODS

All Burkitt's cases diagnosed from 1969 to 2006, from all over Uganda, at the Makerere University's Department of Pathology, were analyzed, to determine seasonal variation. This was done by evaluation of monthly and rainy versus dry season prevalence.

STATISTICAL ANALYSIS

The Wilcoxon test was used in both cases, to assess the statistical significance of differences in the diagnostic rates of Burkitt's lymphoma, in comparison to nonspecific chronic inflammation, using the total as the denominator. Yearly variation in prevalence was examined by a Chi-square test for linear trend. Mann-Whitney tests were done to compare the climatic regions. Multivariate analysis of variance (MANOVA) was used to test for differences when gender, seasons and climatic regions were factored in.

RESULTS

Although monthly frequencies varied considerably over the period, none of the differences were statistically significant (Pearson's 15.199, degrees of freedom df = 11, P = 0.174). Likewise, there was no statistically significant difference in the total number of Burkitt's and nonspecific chronic inflammation biopsies handled at the Department during the rainy and dry seasons.

CONCLUSION

Although the 38-year period gave us sufficient numbers to use the Edward's method for seasonality, it also meant that a lot of seasonal changes that occurred during the period were not taken into consideration. We hence feel that a review of this data with weather experts, so as to group the biopsies into accurate rainfall and dry patterns, would yield a more authoritative publication.

Pediatric malignancies, treatment outcomes and abandonment of pediatric cancer treatment in Zambia

BACKGROUND

There exist significant challenges to the receipt of comprehensive oncologic treatment for children diagnosed with cancer in sub-Saharan Africa. To better define those challenges, we investigated treatment outcomes and risk factors for treatment abandonment in a cohort of children diagnosed with cancer at the University Teaching Hospital (UTH), the site of the only pediatric oncology ward in Zambia.

METHODS

Using an established database, a retrospective cohort study was conducted of children aged 0-15 years admitted to the pediatric oncology ward between July 2008 and June 2010 with suspected cancer. Diagnosis, mode of diagnosis, treatment outcome, and risk factors for abandonment of treatment were abstracted from this database and clinical medical records.

RESULTS

Among 162 children treated at the UTH during the study time period that met inclusion criteria, only 8.0% completed a treatment regimen with most of the patients dying during treatment or abandoning care. In multivariable analysis, shorter distance from home to the UTH was associated with a lower risk of treatment abandonment (Adjusted Odds Ratio [aOR]  = 0.48 (95% confidence interval [CI] 0.23-0.97). Conversely maternal education less than secondary school was associated with increased risk for abandonment (aOR = 1.65; 95% CI 1.05-2.58).

CONCLUSIONS

Despite availability of dedicated pediatric oncology treatment, treatment completion rates are poor, due in part to the logistical challenges faced by families, low educational status, and significant distance from the hospital. Alternative treatment delivery strategies are required to bring effective pediatric oncology care to the patients in need, as their ability to come to and remain at a central tertiary care facility for treatment is limited. We suggest that the extensive system now in place in most of sub-Saharan Africa that sustains life-long antiretroviral therapy for children with human immunodeficiency virus (HIV) infection be adapted for pediatric cancer treatment to improve outcome.

International variations in childhood cancer in indigenous populations: a systematic review

Although the cancer burden in indigenous children has been reported in some countries, up to now, no international comparison has been made. We therefore aimed to assess the available evidence of the burden of childhood cancer in indigenous populations. We did a systematic review of reports on cancer incidence, mortality, and survival in indigenous children worldwide. Our findings highlight the paucity of accessible information and advocate the pressing need for data by indigenous status in countries where population-based cancer registries are established. The true extent of disparities between the burden in the indigenous community needs to be measured so that targeted programmes for cancer control can be planned and implemented.

Pediatric Pathology Services in Africa

Context.—Like other pathology services in developing settings, pediatric pathology in Africa is faced with major challenges such as limited access to resources and few opportunities for professional advancement. Additionally, the discrepancy between the large burden of pediatric diseases, many of which individually are rare enough to prove challenging to the general pathologist, and the amount of specialized training available compounds the underlying problems and makes the provision of a high-quality service difficult. Pediatric neoplasms in particular are a chief cause for concern among general pathologists practicing in Africa.

Objectives.—To provide relevant pediatric pathology information with an emphasis on pediatric malignancies to pathologists practicing in Africa, where children represent a very high proportion of the population and training in pediatric pathology is incomplete.

Data Sources.—Authors' experience and relevant literature.

Conclusions.—The limitations inherent in working within a low-resource setting may be reduced by thoughtful and purposeful triaging of specimens, prudent use of cytology in facilitating rapid and inexpensive diagnoses, and collaboration within and outside of the continent. Increased investment in and advocacy for child health, including the creation of additional hospitals dedicated to the care of children, are likely necessary to significantly advance children's health in the region.

Solid tumors in Turkish children: a multicenter study

BACKGROUND

This paper presents a detailed incidence study on childhood solid tumors comprising a histopathology-based documentation of benign and malignant lesions.

METHODS

The Ankara Pediatric Pathology Working Group collected databases of pediatric solid tumors from six pediatric reference centers in order to analyze the incidence, distribution and some epidemiologic characteristics of the tumors and to establish a multicenter database for further studies. A five-year retrospective archive search was carried out. Excluding epithelial tumors of the skin, leukemia, lymphoreticular system neoplasias, metastatic tumors, and hamartomas, 1362 solid tumors in 1358 patients were classified according to age, sex, localization, histopathology and clinical behavior.

RESULTS

The male/female ratio was 0.9; 14.8% (201) of the patients belonged to 0-1 year age group, 20.7% (281) to 2-4 years, 25.9% (352) to 5-10 years, 22.2% (301) to 11-14 years, and 16.4% (223) to 15-18 years. Among all tumors, 708 (52.0%) were malignant, 645 (47.4%) benign tumors, 2 (0.1%) borderline tumors, and 2 (0.1%) unknown behavioral tumors. Malignant tumors were found in 50.2% (357) of female patients and in 54.0% (349) of male patients. A balanced distribution between benign and malignant entities among children under 18 years was observed. Comparison between the age groups revealed malignant cases outnumbered benign cases under 4 years of age while benign tumor numbers increased after 10 years of age. The most common entities in the malignant group were of sympathetic nervous system origin, while soft tissue tumors far outnumbered the others in the benign group.

CONCLUSIONS

We conclude that the cancer patterns of children in the Ankara region mostly resemble with those of the western population. This study provides useful information on the diagnosis of solid tumors in children and highlights variations in cancer incidence in different age groups.

Pediatric malignancies in Kano, Northern Nigeria

BACKGROUND

With effective immunization control of several devastating childhood infections in the developing world, non-infectious diseases such as malignancies have become increasingly important causes of pediatric morbidity and mortality. Therefore this 10-year retrospective study was undertaken to evaluate and document the pattern of childhood cancers in our locality.

METHODS

We reviewed 438 childhood (≤15 years) malignancies diagnosed at the histopathology and hematology laboratories of our teaching hospital in a 10-year period (2001-2010).

RESULTS

The 438 malignancies comprised 10.9% of all cancers. The maligancies frequently seen in early childhood (0-4 years) accounted for 46.1% and in late childhood (5-9 years) for 34.7%. Retinoblastoma (30.6%), Burkitt lymphoma (19.9%) and acute leukemia (16.9%) were the most common pediatric cancers. Unlike in most other parts of the world, acute myeloid leukemia was slightly more prevalent than acute lymphoblastic leukemia.

CONCLUSIONS

Although there were notable differences, our findings were in broad agreement with those of most other sub-Saharan African series, but differed markedly from those in the Western world and other high income countries. Further studies are required to identify the environmental factors for the high prevalence of nonfamilial retinoblastoma and possibly acute myeloid leukemia.

Hodgkin lymphoma at the paediatric oncology unit of gabriel touré teaching hospital, bamako, mali: 5-year experience

Introduction. The aim of this retrospective, unicentric study over 5 years is to describe the epidemiologic, pathologic, clinic and therapeutic aspects of children treated for Hodgkin lymphoma in our paediatric oncology unit. Patients and Methods. From January 2005 to December 2009, all children under 18 years of age, with Hodgkin lymphoma were included in this study. The treatment protocol was the GFAOP (Groupe Franco-Africain d'Oncologie Pédiatrique) Hodgkin lymphoma treatment protocol. Results. During the study period, 217 cancer cases were diagnosed in our centre. Of these cases, 7 were Hodgkin Lymphoma (LH) (0.04%). The mean age was 11.7 years. The sex-ratio was 6/1. 4% (5/7) of patients were stage IIB and 28.6% (2/7) stage IIIB of Ann-Arbor classification. There were 3 cases (42.8%) of sclero-nodular subtype, 2 cases (28.6%) of lymphocyte-rich classical HL subtype, 1 case (14.3%) of mixed cellularity and 1 case (14.3%) of lymphocyte depleted subtype. With a median followup of 37 months, 5 patients (71.4%) are alive, and 2 patients (28.6%) died. Conclusion. Broader multicentric studies are needed for more accurate data on this malignancy.

Pediatric cancer spectrum in Kenya: a histopathologic review

BACKGROUND

Pediatric malignancies constitute a unique health care burden especially in resource-poor settings such as Africa, and the use of external epidemiologic data in managing these children may lead to erroneous approaches.

METHODS

A retrospective histopathologic analysis of 6,771 pathology reports between March 1992 and August 2006 was undertaken in children under the age of 18. Data were derived from the Kijabe Hospital pathology database, which receives pathologic specimens from 70 different mission hospitals, clinics, and regional hospitals throughout Kenya.

RESULTS

1,217 of these specimens represented malignancies. The top ten pediatric malignancies were Burkitt's lymphoma (16.6%), non-Hodgkin's lymphoma (8.5%), Hodgkin's lymphoma (7.6%), Kaposi's sarcoma (7.6%), osteosarcoma (7.3%), gonadal germ-cell tumors (5.8%), rhabdomyosarcoma (3.5%), nephroblastoma (3.4%), epithelial carcinoma (2.8%), and chondrosarcoma (1.8%).

CONCLUSION

Comparison with several previous African and western pediatric cancer databases is undertaken, revealing significant trends useful for the care of children with cancer in the region.

Spatial distribution of Burkitt's lymphoma in Kenya and association with malaria risk

Endemic Burkitt's lymphoma (BL) is the most common paediatric malignancy in equatorial Africa and was originally shown to occur at high-incidence rates in regions where malaria transmission is holoendemic. New ecological models of malaria that are based on both parasite prevalence and disease have been described. In this study, we examined district level data collected from paediatric BL cases in Kenya from 1988 through 1997 and assessed whether the distribution of district level incidence rates could be explained by new ecologic estimates of malaria risk. Chi-square tests and log-linear regression models were used to evaluate these associations. An association with tribe of origin as a factor also was examined. The 10-year average annual incidence rate (IR) for Kenya was 0.61 per 100,000 children. Incidence rates varied by malaria transmission intensity as follows: low malaria risk (BL IR = 0.39), arid/seasonal (0.25), highland (0.66), endemic coast (0.68), and endemic lake (1.23) (chi(2) = 11.32, P = 0.002). In a log-linear model, BL rates were 3.5 times greater in regions with chronic and intense malaria transmission intensity than in regions with no or sporadic malaria transmission (odds ratio = 3.47, 95% confidence interval = 1.30-9.30), regardless of tribe. Although crude tribe-specific incidence rates ranged between 0.0 and 3.26, tribe was not associated with BL after controlling for malaria. These findings support the aetiologic role of intense malaria transmission intensity in BL.

Spatial clustering of endemic Burkitt's lymphoma in high-risk regions of Kenya

Endemic Burkitt's lymphoma (eBL), the most common childhood cancer in sub-Saharan Africa, occurs at a high incidence in western Kenya, a region that also experiences holoendemic malaria. Holoendemic malaria has been identified as a co-factor in the etiology of this cancer. We hypothesized that eBL may cluster spatially within this region. Medical records for all eBL cases diagnosed from 1999 through 2004 at Nyanza Provincial General Hospital were reviewed for case residential information to examine this hypothesis. Two cluster detection methods, Anselin's Local Moran test for spatial autocorrelation and a spatial scan test statistic, were applied to this residential data to determine whether statistically significant high- and low-risk areas were present in the Province. During the 6-year study period, 272 children were diagnosed with eBL, with an average annual incidence of 2.15 cases per 100,000 children. Using Empirical Bayes smoothed rates, the Local Moran test identified 1 large multi-centered area of low eBL risk (p-values < 0.01) and 2 significant multi-centered clusters of high eBL risk (p-values < 0.001). The spatial scan detected 3 small independent low-risk areas (p-values < 0.02) and 2 high-risk clusters (p-values = 0.001), both similar in location to those identified from the Local Moran analysis. Significant spatial clustering of elevated eBL risk in high-malaria transmission regions and of reduced incidence where malaria is infrequent suggests that malaria plays a role in the complex eBL etiology, but that additional factors are also likely involved.

Cancer mortality patterns in Ghana: a 10-year review of autopsies and hospital mortality

Background

Cancer mortality pattern in Ghana has not been reviewed since 1953, and there are no population-based data available for cancer morbidity and mortality patterns in Ghana due to the absence of a population-based cancer registry anywhere in the country.

Methods

A retrospective review of autopsy records of Department of Pathology, and medical certificate of cause of death books from all the wards of the Korle-Bu Teaching Hospital (KBTH), Accra, Ghana during the 10-year period 1991–2000 was done.

Results

The present study reviews 3659 cancer deaths at the KBTH over the 10-year period. The male-to-female ratio was 1.2:1. The mean age for females was 46.5 [Standard Deviation (SD), 20.8] years, whilst that of males was 47.8 (SD, 22.2) years. The median age was 48 years for females and 50 years for males.Both sexes showed a first peak in childhood, a drop in adolescence and young adulthood, and a second peak in the middle ages followed by a fall in the elderly, with the second peak occurring a decade earlier in females than in males. The commonest cause of cancer death in females was malignancies of the breast [Age-Standardized Cancer Ratio (ASCAR), 17.24%], followed closely by haematopoietic organs (14.69%), liver (10.97%) and cervix (8.47%). Whilst in males, the highest mortality was from the liver (21.15%), followed by prostate (17.35%), haematopoietic organs (15.57%), and stomach (7.26%).

Conclusion

Considering the little information available on cancer patterns in Ghana, this combined autopsy and death certification data from the largest tertiary hospital is of considerable value in providing reliable information on the cancer patterns in Ghana.

Socioeconomic constraints to effective management of Burkitt's lymphoma in south-eastern Nigeria

This paper presents health outcomes and associated socioeconomic factors of 41 children admitted to a tertiary care institution in south-east Nigeria with Burkitt's lymphoma (BL) between 1987 and 2004. BL responds well to chemotherapy and does not pose a significant threat to health in industrialized nations. However, in resource-poor settings where it is endemic, socioeconomic factors significantly affect access to care for affected children, making this readily treatable condition a cause of considerable distress and early death in affected children. Half of the children reported in this paper presented with late stage disease. Although laboratory facilities were available, they were not accessible to all the children. Nearly a quarter of parents of these children could not afford the cost of confirmatory tests, and about a fifth (n = 8; 19.5%) of the children received no chemotherapy because of their parents' inability to pay. Only 21 of 41 children (51.2%) remained on treatment long enough (at least 12 weeks) to enable them to be confirmed either as short-term cure (n = 9; 64.3%), or as early relapse (n = 2; 4.9%). Owing to financial constraint, 13 of the parents (31.7%) withdrew their children against medical advice (n = 7; 17.1%) or left the hospital (n = 6; 14.6%). To address the challenge posed by these factors, we call for the establishment of a regional BL programme in Africa to help establish a critical mass of resources (human and material) to facilitate the development of an effective and accessible control programme in the region.

Oral tumours in Tanzanian children based on biopsy materials examined over a 15-year period from 1982 to 1997

AIM

To provide information on the types and distribution of oral tumours and tumour-like lesions occurring in a Tanzanian child population aged 0-16 years.

DESIGN

Retrospective study of biopsy results from hospital records from 1982-1997.

SETTING

Department of Histopathology, the Muhimbili Medical Centre (MMC) in Dar es Salaam. INTERVENTION/ METHODS: A total of 158 biopsy results, from 75 girls and 83 boys, were retrieved and studied.

RESULTS

Malignant tumours were the most frequent (43.0%) followed by benign tumours (30.4%) and tumour-like lesions (26.6%). Burkitt's lymphoma was the most frequent malignant tumour accounting for 88.2% of all malignancies followed by squamous cell carcinoma (4.4%) and oral Kaposi's sarcoma (2.9%). Fibroma, papilloma and haemangioma were the most frequent benign tumours constituting 27.1%, 14.6% and 12.5%, respectively. Odontogenic cysts were the most frequent tumour-like lesions (28.6%) followed by fibrous dysplasia (19%) and giant cell granuloma (16.7%).

CONCLUSION

The six most common oral lesions were Burkitt's lymphoma, fibroma, odontogenic cysts, fibrous dysplasia, papilloma and giant cell granuloma.

Epstein-Barr virus (EBV) and human disease: facts, opinions and problems

The human herpesvirus, Epstein-Barr virus (EBV), has classically been associated with two pathologies with frequencies approaching 100%. One of these, Burkitt's lymphoma (BL), is of B-cell origin and the other, nasopharyngeal carcinoma (NPC), is a tumour of poorly differentiated epithelial cells. More recently, EBV had been identified with frequencies from a few percent to 100% (in one case) with a variety of other malignancies. These include Hodgkin's disease (HD; where in the west, the frequency of association is about 50%), sino-nasal T-cell lymphomas, lymphoepitheliomas, some sarcomas and breast cancers, other cancers from the head and neck, and lymphomas arising in patients with immune dysfunctions. Since EBV is ubiquitous, with the vast majority of the world's population having met and seroconverted to the virus, the diversity of tumours with which it has now been associated represents a substantial health burden. In a recent IARC monograph, EBV was classified as a group 1 carcinogen. Here, the data on BL and NPC, as they relate to geographical restrictions, viral strain variation, co-factors in disease, and genetic components are reexamined. We raise the question whether in their origins, these tumours genuinely reflect distinct and independent events, as deemed at present, or may represent a response by different cell types to common extracellular factors. For example, a situation in Kenya apparently existed in the past, where both BL and NPC were observed in ethnic Africans with roughly equal frequencies; more recently, in Kenya, EBV has been identified in nearly 100% of the tumours in children with HD. We also consider tumours where the viral association is reportedly of low frequency, and offer explanations for these data, including the possibility of loss of the viral genome once malignancy has been initiated. If this phenomenon occurs as a frequent secondary event, EBV could be an even greater health risk than presently believed.