Improving Survival in Patients with Chronic Lymphocytic Leukemia - Population Based Study
Authors: Trneny Marek , Obrtlikova Petra , Schwarz Jiri , Pavlik Tomas , Muzik Jan , Dusek Ladislav 
Published: October 2019

Abstract
Abstract 2852

Background:
The chronic lymphocytic leukemia is the most frequent leukemia in the western world predominantly diagnosed in older population. It is still considered to be incurable disease, but the significant proportion of patients do not require any treatment during the course of disease. The outcome is influenced by many factors including leukemia biology, patient's status, complications based on immune dysfunction, treatment choice, supportive care and other factors. Clinical trials are focused on highly selected population in need of treatment. Population based data providing the full picture is extremely rare, especially with the treatment data. The presented population-based study provides the full picture of CLL population including the untreated as well treated cohorts in different age and gender subgroups.

Methods:
Using data from the nationwide, population-based Czech Cancer Registry (CCR) and Czech population life-tables provided by the Czech Statistical Office to the Human Mortality Database stratified by age, sex, and calendar time we characterized trends in incidence, mortality and prevalence for all pts diagnosed with CLL in Czech Republic 1979–2008 and relative survival for patients diagnosed in five calendar periods (1980–1984, 1985–1989, 1990–1994, 1995–1999, 2000–2003). All computations were performed using Stata 10.1™ software.

Results:
Altogether 13, 162 pts with CLL diagnosis have been reported to the CCR from 1979 till 2008. Median age 70 years at diagnosis remains unchanged during the whole period, the male/female ratio was 1.5: 1. The CLL incidence increased from 3.3 in 1979 to 5.6 per 100 thousands inhabitants in 2008. The therapy was administered in 54% of all patients, with the significant trend to decrease with calendar period from 60.4% for pts dg in 1980–84 period to 42.3% in 200019403 period. The treatment was administered in 70.2% of pts younger than 60 y compared to 50.1% of older than 60y with the trend to decreased number of treated pts during the time in both cohorts (from 78.5% to 55.3% for younger and from 55.4% to 38.7% for older cohort). The improvement in five years relative survival ratios (RSRs; 95% confidence interval) with calendar period was observed for all patients starting at 0.46 (0.39–0.53), 0.48 (0.42–0.55), 0.52 (0.46–0.59), 0.60 (0.54–0.66) to 0.69 (0.62–0.74). The 5 y RSRs was better for untreated patients compared to treated pts resp. with improvement in both cohorts from 0.53 (0.44–0–62) and 0.34 (0.25–0.45) resp. in 1980–4 period to 0.77 (0.70–0.84) and 0.51 (0.42–0.60) resp. in 2000–3 period. The same trend was observed for young and old, untreated and treated pts. The females have significant better outcome compared to males in all cohorts, young as well old, untreated as well treated.

Conclusions:
In this large population-based study with more than 13, 000 patients we confirmed the increased CLL incidence together with decreased need of treatment which can be explained by the higher number of patients diagnosed in early stages in the recent time. The patients without need of treatment have siginificantly better 5y RSRs compared to pts with need of treatment, the females have significantly better 5y RSRs compared to males consistently in all subgroups. The patient's survival was improved with calendar period for the whole CLL population as well for the younger and older, females and males, untreated as well treated cohort.

Disclosures:
No relevant conflicts of interest to declare.