Epidemiology of hairy cell leukemia in Iceland

Prospective long-term follow-up after first-line subcutaneous cladribine in hairy cell leukemia: a SAKK trial

Hairy cell leukemia (HCL) remains an incurable disease. However, first-line treatment with either intravenous or subcutaneous cladribine generally leads to long-lasting remissions. Although there are excellent long-term data for intravenous application, similar data regarding subcutaneous administration are lacking. We therefore analyzed the long-term outcome of 3 prospective multicenter clinical trials on subcutaneous cladribine performed by the Swiss Group for Clinical Cancer Research (SAKK), which recruited 221 patients with classical HCL between 1993 and 2005. Median overall survival from start of treatment was not reached. Pretreatment anemia, higher Eastern Cooperative Oncology Group score, and higher age were associated with poorer overall survival in multivariable analysis, whereas early progression at 24 and 36 months had no significant impact on overall survival. Second-line treatment was necessary in 53 (23.7%) patients after a median of 5 (range, 0.2-20.4) years, and first retreatment was mainly monotherapy with cladribine (66%) or rituximab (15.1%) or a combination of these drugs (15.1%). A total of 44 (19.9%) patients developed second primary malignancies with a median time to occurrence of 5.7 (range, 0.01-17.5) years. Second primary malignancies were the main cause for death (14; 27.5%). Compared with a matched normal Swiss population, the incidence of second primary malignancies was not increased. However, survival of patients with HCL was slightly inferior by comparison (P = .036). In conclusion, the outcome of HCL patients treated with subcutaneous cladribine is excellent, and in most patients, 1 cycle of subcutaneous cladribine is sufficient for long-term disease control.

Skin changes in hairy cell leukemia

Skin lesions have been reported in about 10–12% of hairy cell leukemia (HCL) patients. Most are etiologically related to autoimmune or infectious processes, although secondary cutaneous neoplasms and drug-induced lesions are also reported. However, leukemia cutis with the direct infiltration of the skin by leukemic cells is extremely rare in HCL patients. This paper reviews the epidemiology, pathogenesis, clinical symptoms, diagnosis, and approach to treating skin lesions in HCL. A literature review of the MEDLINE database for articles in English concerning hairy cell leukemia, skin lesions, leukemia cutis, adverse events, infectious, cutaneous, drug reactions, neutrophilic dermatoses, secondary neoplasms, and vasculitis was conducted via PubMed. Publications from January 1980 to September 2020 were scrutinized. Additional relevant publications were obtained by reviewing the references from the chosen articles.

A population-based study of hairy cell leukemia over a period of 20 years

There are limited population-based studies of hairy cell leukemia (HCL), a rare chronic lymphoproliferative disorder of B-cells. We conducted a population-based study that included all patients diagnosed with HCL between 1996 and 2016 in Western Normandy. Recorded data focused on medical history, clinical presentation, biological results, treatment modalities in the first line and in relapsed/refractory patients and the occurrence of secondary malignancies. One hundred and twenty-three HCL patients were registered in the database. HCL represented 0.7% of all malignant hematological disorders and 3.0% of all leukemia. The overall age-standardized incidence ratio (SIR) was 0.39/100,000 inhabitants in men and 0.09/100,000 in women, and it remained stable over the 20-year period analyzed. One hundred and seven patients (88%) received first-line treatment, 33 patients (27%) received at least 2 lines of treatment and 14 patients (11%) received more than 2 lines. Cladribine used as first-line treatment induced a high hematological complete response (HCR) rate of 92%. The median overall survival (OS) was over 15 years, with 5-year and 10-year survival rates of 84% and 70.5%. No significant differences in OS were observed between men and women, between the calendar periods studied or between patients who received a single line treatment with IFN-α or PNA. The risk of relapse was higher with IFN-α treatment, requiring subsequent treatments in that patients. The time to next treatment (TTN) tends to be longer for PNAs compared to IFN-α even if difference is not significant. Secondary cancers were observed in 9/123 patients (7.3%) with solid tumors in 8 patients and hematological malignancy in one patient. Our data confirm in real life that single courses of cladribine administered to patients with HCL induce high response rates, the majority of which are HCR. Relapses seem less frequent than with IFN-α and the administration schedule is less restrictive for the patients. The emergence of chemo-immunotherapy and the development of effective new drugs such as recombinant immunotoxins and BRAF targeting will offer new possibilities in the management of HCL patients.

Treatment of hairy cell leukemia: long-term results in a developing country

Twenty-nine consecutive patients with hairy cell leukemia (HCL) were treated in two institutions with interferon (IFN, n = 18) or cladribine (n = 11), between July 1987 and May 2011. Median age was 62 (range 29-83) years; there were 21 males and 8 females. Seven of the 18 patients in the IFN group (39%) achieved a complete remission (CR), whereas all the patients in the 2-CDA group entered a CR. Three patients in the 2-CDA group relapsed and needed an additional course of the drug, 2, 3 and 6 years after the initial one. The median overall survival (OS) of the whole group has not been reached, being above 217 months, the 217-month OS being 91%. The survival of patients treated with either IFN or 2-CDA was not statistically different (94% OS at 217 months versus 91% OS at 133 months, respectively). The data that we present here suggest that treatment of HCL with either 2-CDA or IFN is equally effective; treatment costs with IFN are substantially lower than those of the purine analog.

Development of hairy cell leukemia in a patient after cardiac transplantation

Post-transplant lymphoproliferative disorders (PTLDs) are well-recognized complications of bone marrow and solid organ transplantation, comprising a heterogenous group of lymphoproliferations with a spectrum of morphologic, phenotypic and molecular features. Although PTLDs are usually Epstein-Barr virus-driven B-cell lymphoproliferations, T/natural killer-cell lymphoproliferations, multiple myeloma, and Hodgkin's lymphoma are also recognized as part of the PTLD spectrum. Hairy cell leukemia, a low-grade B-cell lymphoproliferation, has not been recognized as part of the PTLD spectrum. We report the first case of hairy cell leukemia occurring after cardiac transplantation. It is unclear whether this case, similar to other cases of low-grade B-cell lymphoproliferations reported after transplantation, is related to immunosuppression and therefore part of the spectrum of PTLDs, or merely represents coincidental event occurring in an immunocompromised patient.

Hairy cell leukaemia: a heterogeneous disease?

The 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 0.32/100,000 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. Age-specific IRs increased rapidly until approximately 40 years then rose at a slower pace. The age-specific IR curves reflected bimodal early- and late-onset 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-period-cohort 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.

A population-based study of hairy cell leukemia in Israel

OBJECTIVES

Few population-based data exist on the incidence and prognosis of hairy cell leukemia (HCL). Our objectives were to study the effect of socio-demographic factors on this rare disease and the risk of second malignancies occurring in HCL patients.

METHODS

We measured crude and age-adjusted incidence rates of HCL based on reporting to the Israel Cancer Registry (ICR) 1991-2001. Using Kaplan-Meier and multivariate analysis, we assessed survival by gender, ethnicity and geographic region. We ascertained additional primary tumors reported in this population and calculated standardized incidence ratios (SIRs) for tumors reported after the diagnosis of HCL.

RESULTS

The ICR registered 147 cases of HCL among males and 34 in females between 1991 and 2001. Age-adjusted incidence rates were 1.62/10(6)/yr for women and 7.97/10(6)/yr for men, with rates 1.5 times higher in Jewish than in non-Jewish (mainly Arab) men. Mean overall survival also differed by ethnicity. In a multivariate model, increasing age at diagnosis (P < 0.001), as well as Arab origin (P = 0.008) were associated with poorer survival but gender did not significantly affect the survival after controlling for age and ethnicity. Other primary malignancies were reported in 20 (11%) individuals, with a predominance of genito-urinary tumors (65%) among males. Secondary genito-urinary tumors were significantly increased above the expected population rates (SIR 3.23, 95% confidence interval: 1.39-6.36, P = 0.008).

CONCLUSIONS

In the Israeli population, age and ethnicity were associated with prognosis of HCL. Variations in disease characteristics, stage of disease at diagnosis or differential access to treatment may contribute to these findings. Patients with HCL appear to be at increased risk for genito-urinary malignancies.