Primary cutaneous lymphomas (CL) represent 27 % of all non-Hodgkin lymphoma (NHL) and are a diverse group of lymphoidneoplasms manifesting heterogeneous clinical, histologic, immunophenotypic, cytogenetic, and molecular features. Given their rarity and heterogeneity, cutaneous lymphomas present substantial diagnostic and therapeutic challenges. There have been no prior large population-based descriptive studies focusing on CL in the United States.
Using the Surveillance, Epidemiology and End Results (SEER) program, we analyzed CL incidence rates (IR) and patient relative survival rates according to race, gender, and histologic type using the 2005 criteria of the World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification. Age-adjusted (2000 US standard) IR were calculated using the SEER*Stat software public use program version 6.4.4 (Surveillance Research Program); IR were expressed as new cases per 1,000,000 person-years and were analyzed by age, gender, race, ethnicity, and year of diagnosis.
3,884 CL were diagnosed in 16 SEER registries during 2001 to 2005. Cutaneous T-cell lymphomas (CTCLs) were the most common group of cutaneous lymphomas (72%), while cutaneous B-cell lymphomas (CBCLs) accounted for 28% of all cutaneous lymphomas. IR for both cell types of CL and their histologic subtypes were all higher among males than females. Overall age-adjusted CL IR were highest among Non-Hispanic Whites and Blacks (11.5/1,000,000 person-years), intermediate in Hispanic Whites (7.9), and lowest among Asian/Pacific Islanders (7.2). CTCL IR were highest among Blacks, whereas the IR of CBCL overall and subtypes were highest among Non-Hispanic Whites and lowest among Blacks. The 5-year relative survival rates for patients with CTCL and CBCL were 87% and 89%, respectively. Patients with primary cutaneous diffuse large B-cell lymphoma-leg type had the poorest survival rates (50%).
CL incidence rates vary markedly by race, gender, and histological type, supporting the notion that the histologic variants of CL represent distinct clinical entities. Further investigations using large populations and molecular tools are warranted to elucidate the etiology of the diverse spectrum of cutaneous lymphomas.
Citation Information: Cancer Prev Res 2008;1(7 Suppl):A81.
Seventh AACR International Conference on Frontiers in Cancer Prevention Research-- Nov 16-19, 2008; Washington, DC