Recent trends in long-term survival of patients with chronic myelocytic leukemia: disclosing the impact of advances in therapy on the population level

Abstract

Within the past decades, major advances in therapy for chronic myelocytic leukemia, including allogeneic hematopoietic stem cell transplantation, interferon therapy, and, more recently, also therapy with the tyrosine kinase inhibitor imatinib, have entered clinical practice. The impact of these advances on long-term survival on the population level should be disclosed as timely as possible. We estimated trends in age specific 5- and 10-year relative survival of chronic myelocytic leukemia patients in the United States from 1990-1992 to 2002-2004. Our analysis is based on records from 8,329 patients aged 15 years or older with a first diagnosis of chronic myelocytic leukemia included in the 1973-2004 data base of the Surveillance, Epidemiology, and End Results Program. Period analysis was used to disclose recent developments with minimum delay. Overall, 5-year relative survival increased from 27 to 49%, and 10-year relative survival increased from 9.5 to 34% between 1990-92 and 2002-04. The increase was most dramatic for younger patients, with 10-year relative survival increasing from 16 to 72% in age group 15-44 years, from 12 to 54% in age group 45-54 years, and from 8 to 34% in age group 55-64 years (p<0.0001 in all cases). Improvements were more modest and not statistically significant, and survival remained at much lower levels among age groups 65-74 and 75+ years. Our analysis discloses a dramatic recent increase in long-term survival of younger patients with chronic myelocytic leukemia which most likely reflects rapid dissemination of advances in therapy on the population level.