Epidemiology and outcomes of lymphomas in children at the Chantal Biya Founfation in Yaounde

Daniel Tarh Ketchen
Paediatrics, The University of Yaounde 1
June, 2017


Introduction: Lymphoma encompasses a heterogeneous group of lymphoproliferative malignant diseases that originates from T and B-cell in the lymphatic system. These are solid tumours characterized by nodal and extra nodal infiltration of lymphoid cells originating from the B and T lineage. Traditionally, lymphomas are classified under two main groups: Hodgkin’s lymphomas and non-Hodgkin lymphomas, which in turn are further divided into other subgroups. Lymphomas in children comprises about 12% of all childhood malignancies and it is the third most frequent cancer, after leukaemia and brain tumours, in Western countries. When treated appropriately, they have very high survival rates. However, there is little data available in Africa and in Cameroon on this disease.

Objectives: The main objective of the study was to describe the epidemiologic pattern and assess the outcome of lymphoma in children at the Chantal Biya Foundation (CBF) in Yaoundé.

Methodology: We carried out a retrospective study. Data were collected from medical records of patients diagnosed with lymphoma at the haematology and oncology unit of the Chantal Biya Foundation (Mother and Child Centre) from January 2008 to December 2015; corresponding to an 8 year period. Those with histological diagnosis and aged 15 years and below were retained for final analysis. The collection of data was done using pre-established forms and analyzed using Epi Info 3.5.4 software at 95% confident intervals. Results were presented in terms of mean ± standard deviation, frequencies and percentages. Survival analysis was performed using Kaplan-Meier methods and the resulting survival distributions was compared with Log-Rank test while associations between variables were assessed using Fischer’s exact and Chi-square tests. P-values less than 0.05 were considered statistically significant.

Results: We sampled 390 cases of lymphomas from the registry of the unit, representing 36% of all childhood cancers at CBF. There was a progressive decrease in the annual frequency of lymphomas from 60 cases in 2011 to 35 cases in 2015. Of the 390 cases retained in our study, 362 (93%) were NHL while 28 (7%) were HL. Of the 28 with HL, the overall mean age was 10.70±3.34 (range 4-15 years). There existed a male predominance (M/F ratio 1.7:1). The most common histologic subtype was nodular sclerosis (76%), followed by mixed cellularity (24%). The major site of lymph node involvement was the cervical region (42%). The majority of patients presented at the advanced stage of disease (79%). The chemotherapy regimen used was COPP/ABV with median duration of 3 months. The 5-year overall survival rate of HL was 74 %.
Similarly, NHL more frequently affected the boys (M/F ratio 1.6:1), with a mean age of 8.55±3.43 (range 1-15 years). Burkitt lymphoma was the commonest histologic subtype of NHL and also among all cancers. Nodal involvement (70%) was greater than extra nodal disease (30%) with the main site being the maxillofacial region (43%). Most patients presented at the late stage of disease (80%) just like in HL. The treatment used depended on the subtypes; LMB 01 and 09 protocol for Burkitt lymphoma, EURO LB 02 for lymphoblastic and ALCL 99 for anaplastic. The 5-year overall survival rate was lower in NHL (51%). There was a significant association between stage of disease and treatment with survival outcome (p-value < 0.05).

Conclusions: Our study showed a decreased annual trend in lymphoid malignancies in children at FCB, with a male predominance, which was demonstrated independently for HL and NHL. While HL was the disease of adolescent (>10 years), NHL was a disease of the younger children population (<10 years). The main localizations of the tumours were maxillofacial and cervical regions, with patients presenting at the advanced stage of the disease. Nodular sclerosis subtype was predominant in HL while Burkitt lymphoma was more prevalent in NHL and was also the most common childhood malignancy. The treatment regimens depended on the histologic subtypes. The 5 year overall survival rate was higher in HL (74%) than in NHL (51%), with treatment and stage of disease been significant prognostic factors.