REVIEW Niger J Paed 2016; 43 (1): 1 –7 Brown BJ A review of the literature on child- hood Burkitt lymphoma in Nigeria DOI:http://dx.doi.org/10.4314/njp.v43i1.1 Accepted: 8th December 2015 Abstract: Background: Burkitt toma as the most common. There Lymphoma is common childhood was a decline in the frequency of Brown BJ ( ) tumour in sub-Saharan Africa but Burkitt lymphoma in Ibadan from Department of Paediatrics, the lack of centralized database on 1960-2010 and in Lagos. Peak University College Hospital, childhood cancer in Nigeria has ages of occurrence ranged from 5- Ibadan, Nigeria. Email: [email protected] made it difficult having a nation- 10 years, more males and children wide picture of its occurrence in from low socio-economic classes the country. were affected. Different centers Objectives: This study was aimed reported predominant involvement at pooling published data from of either the jaw or the abdomen across the country with the hope but there were slightly more cen- of providing an overview of the ters with predominance of the jaw. profile of the disease in Nigeria. Retrospective studies yielded an Methods: literature search was estimated survival of 15-23% carried out on Pub Med/ while the Event Free Survival MEDLINE and Cochrane data- probabilities at two years was 43% bases for all articles published and 48% for the Nigerian centers between January 1975 and July that participated in an international 2015 using search strings such as study. children, cancer, Burkitt’s, epide- Conclusion: Burkitt Lymphoma is miology, prevalence, treatment a common tumour in Nigeria. Es- and Nigeria. Based on specific tablishment of Cancer registries criteria, 39 studies were included. for better data capture and funding Results: Burkitt Lymphoma was for better treatment outcomes is the most common childhood ma- recommended. lignancy in most parts of the country accounting for 18.3- Key words: Burkitt Lymphoma; 65.0% of malignant tumours but a Nigeria; childhood; tumours; can- few centers observed Retinoblas- cer Introduction other extranodal sites4. Epstein Barr virus (EBV) is found in nearly all cases. Sporadic Burkitt lymphoma Burkitt lymphoma is an aggressive B cell Non- occurs worldwide; with no specific geographic or cli- Hodgkin’s lymphoma characterized by a high degree of matic association. It accounts for 1%–2% of lymphoma proliferation of the malignant cells and deregulation of in adults and up to 40% of lymphoma in children in the the c-MYC gene1. It has three variants namely the en- United States5. The abdomen, especially the ileocecal demic, sporadic and HIV –associated forms2. The high- area, is the most common site of involvement; other est incidence of the endemic form occurs in the lym- sites that may be involved include the ovaries, kidneys, phoma belt lying between latitude 10 degrees north and omentum, and Waldeyer’s ring. Only about 15% of south of the equator and characterized by malaria cases of sporadic Burkitt Lymphoma harbor the EBV holoendemicity2. It is therefore common in Tropical genome6. Immunodeficiency-associated Burkitt lym- Africa and in Papua New Guinea3. phoma occurs mainly in patients infected with HIV but has also been reported in organ transplant recipients7. Endemic Burkitt lymphoma refers to those cases occur- Nigeria is the most populous country in Africa and the ring in African children, usually 4–7 years old, involv- country’s 2006 Population and Housing Census placed ing the bones of the jaw and other facial bones, as well the country’s population at 140,431,7908. It is divided as kidneys, gastrointestinal tract, ovaries, breast, and into a Federal Capital Territory and thirty-six states and 2 the states are divided into six geopolitical zones: North- volving all childhood malignancies including leukae- West, North-East, North-Central, South-East, South- mias and solid tumours. Studies that were based on solid South, and South-West. The country lies on the west tumours alone were analyzed separately and the ranking coast of Africa between latitudes 4º16' and 13º53' north of Burkitt lymphoma stated but frequency figures down- and longitudes 2º40' and 14º41' east and therefore falls played since they would not be representative of the within the lymphoma belt8. Burkitt lymphoma is there- entire spectrum of childhood tumours. fore expected to be common in Nigeria, given its geo- graphical location. Studies from several states of the A total of 39 articles on Burkitt Lymphoma in Nigeria country report Burkitt Lymphoma to be the most com- were reviewed. Sixteen studies were from the south west mon type of cancer in children9–11 but a few have re- zone constituting the majority, followed by the North ported the contrary12,13. A centre within the country has West, south east and north central zones with 8, 7 and 6 reported a downward trend in the relative frequency of studies respectively while the south-south and north east Burkitt Lymphoma with respect to other tumours but zones had two and one articles respectively1, one article this has not been appraised in most parts of the country was based on 2 centres). Clinical or clinic-pathologic 12. In terms of clinical presentation, whilst some centres studies were used for analysis of socio-demographic have reported the jaw or face as the predominant site features and predominant sites of tumour involvement affected11,14, others have reported the abdomen as the and in this regard, emphasis was placed on studies that most common site15,16. included all tumours confirmed either by cytology of fine needle aspirate or histology from a surgical biopsy. Incidentally, there is no national cancer registry or data- Studies based exclusively on surgical biopsy specimen base to provide a general view of the situation nation- were analyzed separately and given less emphasis be- wide. There is also paucity of population based Cancer cause the usual method of diagnosing Burkitt lymphoma registries and many of publications on childhood cancer in Africa is through cytology of fine needle aspirates of are based on reports from Pathology departments or accessible tumour and so analyzing only studies based clinical reviews. There is therefore lack of national inci- surgical biopsies is likely to exclude a significant pro- dence data for the disease which could serve as baseline portion of cases and therefore introduce bias to the re- data and guide policy formulation towards management sults17. and control. This is important given the association of For centres with multiple publications on Burkitt lym- the tumour with malaria and therefore the potential to phoma over time, the most recent was used for preva- control its occurrence with malaria control measures2. lence figures. However, for analysis of trend, all studies The aim of this study was to compile published data on that met the inclusion criteria over time were used. Burkitt lymphoma across the country in order to summa- rize them and provide an overview of the national pat- tern of the disease. The objectives of this study were to Results describe the relative frequency, socio-demographic fea- Prevalence tures, predominant clinical sites of involvement and treatment outcomes of Burkitt lymphoma in Nigeria. Ten centres reported relative frequency of Burkitt lym- The ultimate aim was to provide a summarized report phoma among all cases of childhood malignant diseases that could serve as a proxy for generalizable data in the confirmed cytologically or histologically (Table 1). absence of a centralized database for childhood cancer. Burkitt lymphoma was the commonest in eight of the In addition, it was hoped that any regional differences in centres namely Enugu, Zaria, Jos, Ekiti, Calabar, Sa- pattern would be highlighted by this review. gamu, Abia and Gwagwalada with prevalence ranging from 18.3 to 65.0% of malignant tumours of child hood in the various centers9–11,18–22. These centres are spread across the FCT and five geopolitical zones but excluding Methodology the north east geopolitical zone. Retinoblastoma was the most common tumour in two centres namely, Ibadan This was a review of published scientific literature on and Kano with Burkitt lymphoma being the second most Burkitt lymphoma in Nigeria between January 1975 and common cancer in both cities12,13 July 2015. Literature search was performed on Pub- . Med / MEDLINE and Cochrane databases for all articles Studies from seven centres were restricted to solid tu- using search strings or key words such as children, can- mours; Burkitt lymphoma was the most common solid cer, Burkitt’s, epidemiology, prevalence, treatment and tumour in four centres namely Sokoto, Ilorin, Port Har- Nigeria. The reference list of articles were also checked court and Ile-Ife as shown in table 223–26. In the fifth for other articles that were not detected by the biblio- centre, Zaria, Burkitt Lymphoma and Retinoblastoma graphic search. The inclusion criteria for each analysis were of equal frequency and ranked highest27. Out of depended on the specific objective targeted by that the remaining two centres, Jos reported Rhabdomyosar- analysis. In general, only studies based on cases from coma as the predominant solid tumour accounting for 31 cancer registries or histopathology departments or clini- percent of the tumours with Burkitt Lymphoma being cal studies confirmed histologically or cytologically the third most common and accounted for 13.8 percent were included. For analysis of relative frequency of of the tumours while in Lagos, Retinoblastoma was Burkitt