IBCL-057: Clinical Characteristics and Survival of Patients with Hairy Cell Leukemia Treated at the National Cancer Institute in Peru from 1999 to 2018

Context Hairy cell leukemia (HCL) is a hematological malignancy (HM) with long survival in patients who receive purine analogs. Objective To describe the clinical characteristics and survival of HCL. Design Retrospective study, from 1999–2018. Setting National Cancer Institute in Peru. Patients HCL. Interventions Cladribine. Main Outcomes Measures Survival curves were drawn according to the Kaplan-Meier method. Results During the study period 24,744 patients with HM were diagnosed, of whom 27 had HCL, accounting for 0.001%. Twenty patients had enough clinical information to be included. The median age was 52.5 years (range, 35–88), and 60% were male. Ninety-five percent (n=19) of patients had indication of receiving any treatment. Eighty percent (n=15) of patients received treatment, of whom 26.6% (n=4), 40% (n=6), and 33.3% (n=5) received cladribine, interferon, and rituximab, respectively. Among patients without treatment, three were lost to follow-up. Fourteen patients had assessment of response: 42.8% (n=6), 42.8% (n=6), and 14.3% (n=2) achieved complete response (CR), stable disease (SD), and progressive disease (PD), respectively. Six patients received second-line treatment; 83% (n=5) received cladribine and achieved CR. With a median follow-up time of 42 months (range 1–181), for the whole cohort, the 5-year overall survival (OS) was 85.9% (95%CI, 54–96.3), and the 10-year OS was 57.2% (95%CI, 8.5–88.1). The median survival time was not achieved. For the cladribine treatment group (first- or second-line treatment) (n=9), the 5-year OS was 100%, and for the non-cladribine treatment group (n=6), the 5-year OS was 80% (95%CI, 20.3–96.9) and the 10-year OS was 0%. The median survival time was 98 months. The difference in survivals between the cladribine vs non-cladribine groups was not statistically significant (p=0.06). Conclusions HCL is rare in Peruvian patients. CR was achieved in all patients who received cladribine regardless the line of therapy. OS for the whole cohort was shorter compared to other reports, probably because most patients received a non-cladribine-based first-line treatment. In our cohort, the cladribine group had an OS of 100%. No patient who received a non-cladribine treatment was alive at 10 years post-diagnosis.