Background: The natural history of chronic lymphocytic leukemia (CLL) is changing, although the reasons (potential changes in the disease's biology or in patterns in patient characteristics, treatment, or referral) are unclear.
Methods: This report uses National Cancer Data Base (NCDB) data, which reflect a hospital-based patient population from a broad spectrum of hospitals in the United States. Age, gender, race/ethnicity, income, treatment, overall survival, and relative survival were evaluated according to time period (1985-1990 and 1991-1995). Comparisons were made with U. S. population figures for 1990 and with series published over the last 70 years.
Results: CLL comprised 22.6% of the 108,396 cases of leukemia in the data base. The risk of developing CLL increased progressively with age and did not plateau; the average age was 69.6 years. At the time of initial diagnosis, 60.5% of patients received no treatment (this proportion increased from 58.1% to 62.7% between the 2 time periods). Overall survival was 48.2% at 5 years and 22.5% at 10 years. The 5-year relative survival was 69.5%, 72.2%, 63.1%, and 41.7% for age groups <40, 40-59, 60-79, and 80+ years, respectively; these rates indicated that CLL, and not comorbid disease, caused the greatest percentage of deaths.
Conclusions: The risk of developing CLL increases progressively with age without plateauing and is 2.8 times higher for older men than for older women. There is an increasing trend toward no treatment at the time of initial diagnosis. Long term overall survival of CLL patients is poor. CLL is a more fatal disease among older individuals because of the disease itself, not because of comorbid conditions.
Copyright 1999 American Cancer Society.