Non Hodgkin lymphoma in Lebanon: a retrospective epidemiological study between 1984 and 2019

Lymphomas are ranked as the fifth most common cancer in Lebanon. There is concern about the need of information regarding the prevalence of lymphoid neoplasm particularly Non-Hodgkin lymphoma (NHL) subtypes in the Lebanese population. This study intended to establish a descriptive status of NHL histological subtypes distribution in Lebanon thus identifying the most common types, knowing that the literature is poor regarding the distribution of lymphoid malignancies particularly NHLs in Lebanon.

A bicenter retrospective descriptive study was performed. Patients aged above 18, diagnosed with NHL between January 1984 and March 2019 and registered in two Lebanese Medical centers were included in this study; 699 medical files were reviewed and the baseline characteristics of the disease were collected. Histological classification was based on the Working Formulation (WF) and World Health Organization (WHO) classification systems, whereas staging was based on the Ann Arbor system. Disease status was monitored with imaging studies.

The mean age at diagnosis was 53.52 ± 17.46 years in the studied population, with 380 (54.4%) males and 319 (45.6%) females. B-cell lymphoma (BCL) accounted for 86.3% while T-cell neoplasms accounted for 13.7%. The most common subtype was diffuse large B-cell lymphoma (DLBCL) (54%) followed by follicular lymphoma (FL) (17.2%). Mantle cell lymphoma (MCL) represented 3% of all BCL and small lymphocytic lymphoma (SLL) comprised less than 2%. Mucosa-associated lymphoid tissue (MALT) and Burkitt's lymphomas represented 3 and 1.7% respectively. 36.5% of the patients had extranodal disease at diagnosis. High-grade tumor represented 80.1% with 33.1% stage IV disease.

These observations indicate that the epidemiological patterns of NHLs in Lebanon were comparable to Western countries. Aggressive lymphomas account for the majority of NHLs in Lebanon.