Improved survival in chronic lymphocytic leukemia in the past decade: a population-based study including 11,179 patients diagnosed between 1973-2003 in Sweden

Abstract

Background: Clinical management of chronic lymphocytic leukemia patients has changed considerably over the last years, reflected in an increased use of prognostic markers, new therapeutic agents and procedures, and supportive care measures. However, to date, clinical trials have not shown a survival benefit.

Design and methods: Using population-based data from Sweden, we assessed variations in survival among all chronic lymphocytic leukemia patients (n=11,179) reported from 1973-2003. Relative survival ratios were computed as measures of patient survival.

Results: Overall we found significantly improved (p<0.0001) 5-, 10-, and 20-year relative survival ratio for the entire cohort during the study period. Improved 5- and 10-year relative survival ratio was found for all age-groups (p<0.0001) and both sexes. Compared to females, however, males had a significantly inferior survival in all age groups and calendar periods (p<0.0001). Younger chronic lymphocytic leukemia patients had a superior survival compared to older chronic lymphocytic leukemia patients, in all calendar periods (p<0.0001). Five-year relative survival ratio has not improved in the youngest chronic lymphocytic leukemia patients since the 1980s; however, older patients have had a continuous improvement in 5 year-relative survival ratio.

Conclusions: The observed improvements are likely due to improved therapeutic developments and supportive care. Our findings suggest that elderly chronic lymphocytic leukemia patients might benefit more from the recently introduced drugs in chronic lymphocytic leukemia. Future clinical trials are needed to better define underlying mechanisms of observed heterogeneity in chronic lymphocytic leukemia survival by age and sex, and evaluate the role of newer chronic lymphocytic leukemia therapy in the elderly.

Figure 1.

Overall relative survival ratios among chronic lymphocytic leukemia patients diagnosed in Sweden 1973–2003.

Figure 2.

Relative survival ratios among chronic lymphocytic leukemia patients diagnosed in Sweden 1973–2003, stratified by age group at CLL diagnosis.

Figure 3.

(A) Relative survival ratios (RSR) among chronic lymphocytic leukemia patients diagnosed at the age of 51–70 years in Sweden 1973–2003, stratified by sex. (B) Relative survival ratios (RSR) among chronic lymphocytic leukemia patients diagnosed at the age of 70+ years in Sweden 1973–2003, stratified by sex.