Hairy cell leukaemia: a heterogeneous disease?

Abstract

SummaryThe US National Cancer Institute's Surveillance, Epidemiology and End Results program was used to develop aetiological clues for hairy cell leukaemia (HCL). Descriptive techniques (age-adjusted incidence trends, age-specific incidence rates (IR), and age distributions-at-diagnosis) were supplemented with mathematical models (two-component mixture, generalized linear regression, and age-period-cohort). There were 2856 cases of HCL diagnosed during 1978-2004 (IR 0AE32/100 000 person-years). IRs were nearly 4-fold greater among men than women and more than 3-fold higher for Whites than Blacks. Temporal trends were stable over time. Agespecific IRs increased rapidly until approximately 40 years then rose at a slower pace. The age-specific IR curves reflected bimodal early-and lateonset age distributions-at-diagnosis (or density plots), with some variation by gender. Among both men and women, a two-component mixture model fitted the data better than a single density or cancer population. Age-periodcohort models confirmed statistically significant age-related effects after full adjustment for temporal trends (calendar-period and birth-cohort effects). In summary, age incidence patterns (rates and bimodal densities) suggested that HCL is a heterogeneous disease, consisting of at least two underlying subgroups and/or cancer populations by age-at-onset. Distinct early-and late-onset HCL populations may reflect different age-related causal pathways, risk factor profiles, and/or stem cells of origin.

Retrospective evaluation of hairy cell leukemia patients treated with 3 different first-line treatment modalities in the last two decades: a single center experience

“…responses until the introduction of the purine nucleoside analogues 2-chlorodeoxyadenosine (cladribine, 2-CdA) and 2′-deoxycoformycin (pentostatin) [3,4,5]. Purine analogues have resulted in higher complete response (CR) rates and durable remissions, and they have become the treatment of choice in most cases [6]. Monoclonal antibodies (i.e.…”

Response of relapsed central nervous system hairy cell leukemia to vemurafenib

“…[1] There have been previous reports of CNS involvement by HCL, but these cases are extremely rare and usually present with highly fatal leptomeningeal disease or direct leukemic brain infiltration. [2][3][4][5] In this report, we describe the durable treatment response of a relapsed BRAF V600E-mutated HCL with extensive CNS involvement to vemurafenib.…”

Update on the Biology and Treatment Options for Hairy Cell Leukemia

“…HCL is more common among those with European or Ashkenazi Jewish ancestry, and Asian countries have a lower incidence of HCL than Western countries [7]. Elderly and African-American patients have decreased survival durations [8]. A few studies have shown that HCL incidence is higher among individuals with a family history of HCL or chronic lymphocytic leukemia [9, 10].…”