Tyrosine kinase inhibitor usage, treatment outcome, and prognostic scores in CML: report from the population-based Swedish CML registry

Abstract

Clinical management guidelines on malignant disorders are generally based on data from clinical trials with selected patient cohorts. In Sweden, more than 95% of all patients diagnosed with chronic myeloid leukemia (CML) are reported to the national CML registry, providing unique possibilities to compile population-based information. This report is based on registry data from 2002 to 2010, when a total of 779 patients (425 men, 354 women; median age, 60 years) were diagnosed with CML (93% chronic, 5% accelerated, and 2% blastic phase) corresponding to an annual incidence of 0.9/100,000. In 2002, approximately half of the patients received a tyrosine kinase inhibitor as initial therapy, a proportion that increased to 94% for younger (<70 years) and 79% for older (>80 years) patients during 2007-2009. With a median follow-up of 61 months, the relative survival at 5 years was close to 1.0 for patients younger than 60 years and 0.9 for those aged 60 to 80 years, but only 0.6 for those older than 80 years. At 12 months, 3% had progressed to accelerated or blastic phase. Sokal, but not European Treatment and Outcome Study, high-risk scores were significantly linked to inferior overall and relative survival. Patients living in university vs nonuniversity catchment areas more often received tyrosine kinase inhibitors up front but showed comparable survival.

Figure 1

Age- and sex-specific incidence of CML per 100 000 inhabitants, year 2002-2010.

Figure 2

Time trends in percentage of patients treated with TKI by age (A) and by residence (university hospital catchment area vs other area) and sex (B).

Figure 3

Relative survival by disease phase at diagnosis (A), sex (CP) (B), and age group (CP) (C). Relative survival was calculated as the ratio of the observed survival in the study population to the expected survival of the general population.

Figure 4

Overall (A,C,E) and relative (B,D,F) survival for patients in CP at diagnosis, per Sokal (A-B), Hasford (C-D), and EUTOS (E-F) score. Differences in survival tested by log-rank test (OS) and Poisson regression model (RS).

Figure 5

RS for patients in CP at diagnosis, by whether or not the patient resided in the catchment area of any of the Swedish university hospitals.