The epidemiology of lymphoma in Jordan: A nationwide population study of 4189 cases according to World Health Organization classification system.

Objective/background: Lymphoma is a common human cancer that shows a variable geographic incidence worldwide. It is the fourth most common cancer in Jordan. Systemic reports of descriptive epidemiology on lymphoma from the Middle East are limited.
Methods: A nationwide multi-institutional retrospective study was conducted covering all major hospitals and laboratories that provide diagnostic services. We collected data on all cases diagnosed with lymphoma between 2014 and 2019. The included variables were patients' age, gender, anatomic site, and the histologic type according to the World Health Organization classification system.
Results: A total of 4189 cases were diagnosed with lymphoma. There was a statistically significant gender difference (p < .05), as 57.5% of patients were males. The peak incidence occurred at age 25-55 years. There were 1,652 (39%) cases of Hodgkin lymphoma (HL) and 2,537 (61%) of non-Hodgkin lymphoma (NHL), where nodular sclerosis (67%) and diffuse large B-cell lymphoma (53%) were the most common subtypes, respectively. The average age-adjusted incidence rates per 100,000 population were 8.01 for all lymphomas, 4.33 for NHL, and 3.16 for HL and all remained stable over the 6 years.
Conclusion: HL is the most common lymphoma in Jordan, with a percentage higher than most of reported studies in Asian and Western countries. It also shows a unimodal distribution of age-specific incidence rates, with a single peak in young adults. The incidence rate of HL is higher than Eastern countries but comparable to the West. In contrast, NHL demonstrates a lower incidence rate than Western countries but a similar distribution of subtypes, as mature T/natural killer-cell lymphomas were rare.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 King Faisal Specialist Hospital & Research Centre. Published by Elsevier Ltd. All rights reserved.)