Survival for patients with chronic leukemias in the US and Britain: Age-related disparities and changes in the early 21st century

Abstract

Background: Chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) are highly treatable conditions occurring primarily in older patients. Lower survival among older people has been reported in both conditions, but newer treatments may change both the overall survival rate and the relative risk associated with aging. Here, we examine survival for patients with CLL and CML in the United States (US) and England.

Methods: Patients with CLL and CML were identified from the Surveillance, Epidemiology, and End Results (US) and National Cancer Registry (England). Five-year relative survival was calculated by major age group. Excess hazard ratios (EHR) by age were calculated for each condition, and multivariable analysis was performed to adjust for the following potential confounders: gender, race or ethnic group (US only), period of diagnosis, and a measure of socioeconomic deprivation (England only).

Results: Five-year relative survival increased for both CLL and CML in both England and the US between 1996-2000 and 2006-2010. However, relative age-related disparities persisted. For CLL, the EHR for death was 9.44 (7.84-11.36) in the US and 6.14 (5.65-6.68) in England for ages 85+ compared to ages 55-64. For CML, the EHR was 3.52 (3.17-3.90) in the US and 4.54 (4.13-4.98) in England for ages 75+ compared to ages 45-64.

Conclusions: Survival improved for patients with chronic leukemias in the early 21st century. However, age-related disparities persist, despite clinical trial evidence that treatment in older adults with chronic leukemia can be safe and effective. Further research to determine the reasons for the lower survival in older patients and greater awareness of this problem may improve survival for older patients with chronic leukemia.

Keywords: chronic lymphocytic leukemia; chronic myeloid leukemia; disparities; period analysis; survival.