title: Non-Hodgkin lymphoma in the developing world: review of 4539 cases from the International Non-Hodgkin Lymphoma Classification Project.
abstract: The distribution of non-Hodgkin lymphoma subtypes varies around the world, but a large systematic comparative study has never been done. In this study, we evaluated the clinical features and relative frequencies of non-Hodgkin lymphoma subtypes in five developing regions of the world and compared the findings to the developed world. Five expert hematopathologists classified 4848 consecutive cases of lymphoma from 26 centers in 24 countries using the World Health Organization classification, and 4539 (93.6%) were confirmed to be non-Hodgkin lymphoma, with a significantly greater number of males than females in the developing regions compared to the developed world (P<0.05). The median age at diagnosis was significantly lower for both low- and high-grade B-cell lymphoma in the developing regions. The developing regions had a significantly lower frequency of B-cell lymphoma (86.6%) and a higher frequency of T- and natural killer-cell lymphoma (13.4%) compared to the developed world (90.7% and 9.3%, respectively). Also, the developing regions had significantly more cases of high-grade B-cell lymphoma (59.6%) and fewer cases of low-grade B-cell lymphoma (22.7%) compared to the developed world (39.2% and 32.7%, respectively). Among the B-cell lymphomas, diffuse large B-cell lymphoma was the most common subtype (42.5%) in the developing regions. Burkitt lymphoma (2.2%), precursor B- and T-lymphoblastic leukemia/lymphoma (1.1% and 2.9%, respectively) and extranodal natural killer/T-cell lymphoma (2.2%) were also significantly increased in the developing regions. These findings suggest that differences in etiologic and host risk factors are likely responsible, and more detailed epidemiological studies are needed to better understand these differences.
authors.affiliation: Department of Pathology, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Anamarija M
authors.initials: AM
authors.lastname: Perry
authors.affiliation: Department of Anatomic Pathology and Cytology, Hotel-Dieu, University Denis Diderot, Paris, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Diebold
authors.affiliation: Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA.
authors.forename: Bharat N
authors.initials: BN
authors.lastname: Nathwani
authors.affiliation: Section of Pathology and Leeds Institute of Molecular Medicine, St. James University Hospital, Leeds, UK.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: MacLennan
authors.affiliation: Institute of Pathology, University of Würzburg, Germany.
authors.forename: Hans K
authors.initials: HK
authors.lastname: Müller-Hermelink
authors.affiliation: Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Bast
authors.affiliation: Center for Collaboration on Research Design and Analysis, College of Public Health, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Boilesen
authors.affiliation: Department of Pathology, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: James O
authors.initials: JO
authors.lastname: Armitage
authors.affiliation: Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA dweisenburger@coh.org.
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Weisenburger
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D019049:Developed Countries; D003906:Developing Countries; D005260:Female; D006801:Humans; D007223:Infant; D016393:Lymphoma, B-Cell / Q000145:classification / Q000453:epidemiology; D008228:Lymphoma, Non-Hodgkin / Q000145:classification* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D014944:World Health Organization; D055815:Young Adult