Epidemiology of hairy cell leukemia in Iceland.
BACKGROUND
Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative disorder. Previous epidemiological studies have mainly focused on cases derived from single institutions or from localized cancer registries. This is the first study in which all cases diagnosed nationwide over a long period of time in a well defined population are analysed. We report the epidemiology of all HCL patients in Iceland, their clinical characteristics, treatment and follow-up.


METHODS
: All patients diagnosed with HCL in Iceland over a 20 year period, were included in this study. Data was collected retrospectively.


RESULTS
Sixteen patients, 13 males and three females were diagnosed with HCL in Iceland from 1981-2000, giving a mean incidence of 4.7/million/year (95% CI: 2.7-7.6) in the population 20 years and older. Eleven patients were treated with a purine analogue, 10 of whom achieved CR. One other patient obtained CR following splenectomy and IFN, giving a total CR rate of 69%. Three other patients (19%) obtained PR, giving a total response rate of 88%. One patient had a variant of HCL and did not respond to any therapy and one patient died of sepsis before any chemotherapy could be given. Six patients with HCL have died, one from complications of HCL. Three patients developed a second malignancy (19%).


CONCLUSIONS
The mean incidence of HCL in Iceland is 4.7/million/year. This is slighty higher than the reported incidence in England and Wales, although not significantly higher. The incidence is based on a nationwide information from a well defined stable and racially homogenous island population. Other results are in accordance with previously published studies.
Kristinsson
Sigurdur Yngvi
SY
Department of Hematology, Landspitali University Hospital, Reykjavik, Iceland. sigrunre@landspitali.is
Vidarsson
Brynjar
B
Agnarsson
Bjarni A
BA
Haraldsdottir
Vilhelmina
V
Olafsson
Orn
O
Johannesson
Gudmundur M
GM
Eyjolfsson
Gudmundur I
GI
Bjornsdottir
Johanna
J
Onundarson
Pall T
PT
Reykdal
Sigrun
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D015994:Incidence; D007943:Leukemia, Hairy Cell / Q000150:complications / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary; D012074:Remission Induction / Q000379:methods; D012189:Retrospective Studies