Burkitt's lymphoma in Kenya: geographical, age, gender and ethnic distribution

Abstract

OBJECTIVE: To show the geographical (Provincial), age, gender and ethnic distribution of Burkitt's lymphoma in patients in Kenya. DESIGN: A retrospective review of patients' records for the years 1988-1992 and a prospective evaluation of patients with BL between 1993 and 1997. These were descriptive and hospitals based studies. SETTING: Kenyatta National Hospital; Kenya's main referral and teaching hospital and seven provincial hospitals. MAIN OUTCOME MEASURES: For each tissue proven Burkitt's lymphoma case the following were required; province of birth and residence, tribe, age, sex, chief complains, physical examination findings, investigation results and tissues result confirming the diagnosis of BL. STATISTICAL METHOD: Mainly proportions were used to compare variables, however Pearson's liner correlation was used to assess the time trends. RESULTS: This study registered 1005 patients; 961 (95.6%) children and 44 (4.4%) adults. 0-14 years the age standardized incidence rate (ASR) of 0.83. Variations documented in the provinces' BL ASR range; 1.8 Coast to 0.23 Rift Valley and increasing yearly trend for both children and adults. The major tribes in Kenya consisted; Luo 29.5%. Luhya (24.1%) and Coastal (16.5%). No patient of Asian or European or Arab extraction was recorded in the study. The age distribution showed no case below two years, a rapid rise from three year 3 (5.6%), and peak at 6 (19.5%) for children and at 17 years (13.6%) years for the adult. Age group 5-9 years had the highest ASR. The male to female (M:F) ratios were; 1.5:1 and 1:1 in children and adults respectively, provincial ratios range; 2.6:1 in Nairobi to 1.2:1 in Nyanza, the tribes range; 3.5:1 in Somali to 1:1 in other tribes between 2 and 14 years old when also males were more than females. Peak time of presentation of symptoms was 4 weeks. Tumour sites were in children; jaw 51.6%, abdomen (25%), combined jaw and abdomen 13.8% and others 9.6% and adults; jaw (4.5%), abdomen (43.2%), combined jaw and abdomen (25%) and other sites (27.3%) 67.6% males and 42.4% female adults had HIV infection and disseminated BL disease. CONCLUSION: The study demonstrates that Burkitt's lymphoma is a childhood disease. The disease distribution is consistent with intermediate risk Burkitt's lymphoma level. Furthermore the distribution varied by province, tribe, age and gender. The variations could be due to environmental factors.