Descriptive Study of Diffuse Large B Cell Lymphoma in Algeria and Tunisia over a Period of 5 Years

Background: Diffuse Large B Cell Lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin's lymphoma (NHL) accounting for approximately 40 % of all NHL cases. The aim of our study is to carry out an epidemiologic description and to compute the incidence of DLBCL in 2North African countries, Algeria and Tunisia.

Patients and methods: This is a multicenter retrospective and descriptive study, covering a period of 5 years (January 2010 - December 2014), carried out in 17 centers in Algeria and 5 centers in Tunisia. Patients aged less than 15 years were excluded. We used the classification of World Health Organization. We used Epi info 6 software to analyze the data.

Results: 1432 cases were identified, 1175 in Algeria and 257 in Tunisia. The sex distribution of DLBCL was as follows: males 837 (58.4 %), females 591 (41.6 %), male-to-female ratio 1.40. The age of patients ranged from 16 to 96 years (median 52 years) and 64.2 % of the patients are less than 60. The incidence estimates for the years 2012 and 2013 are respectively 0.86 and 0.87 for 100,000 inhabitants. The most frequent occupation of the cases is farmworker (11.5%). The average time between the date of diagnosis and clinical examination is 31 days. The average delay between the first clinical sign and the date of diagnosis is 133 days. A familial history of cancer is found in 10% of the cases. The lymph node biopsy was undertaken in 30.7% of the cases in the cervical area and in 15% of cases in the mediastinal area. A reexamination of the slides was undertaken in 20% of cases while 61.6% of them were found to be advanced clinical stages (III + IV). Splenomegaly was found in 16% of the cases and hepatomegaly in 7%. ORL damage was found in 16% of the cases and marrow infiltration in 10.2%. A Prognostic Score IPI ≥ 2 is found in 38% of the patients.

Comments: On a previous Algerian study concerning all lymphomas diagnosed over a period of 6 years (2007-2012) (Journal of Hematology No. 10-11, 2015), 485 new cases of lymphoma were diagnosed on average per year. In the present study, the average number of new cases of DLBCL was 235 and the average proportion was 48% of all lymphomas. It should be emphasized that all cases underwent an immunohistochemical study and that lymphatic cases were excluded (digestive, bone, skin). The national incidence rate is low compared to that of international studies, a fact that is probably due to difficulties in the diagnosis including lack of implementation of immunohistochemistry techniques in our region.