Population-Based Testing and Treatment Characteristics for Chronic Myelogenous Leukemia

National and international hematology/oncology practice guidelines recommend testing for the BCR-ABL mutation for definitive diagnosis of chronic myeloid leukemia (CML) to allow for appropriate treatment with a tyrosine kinase inhibitor (TKI). The purpose of our study was to describe population-based testing and treatment practice characteristics for patients diagnosed with CML.

We analyzed cases of CML using 2011 data from 10 state registries that are part of the Centers for Disease Control and Prevention (CDC)'s National Program of Cancer Registries. We describe completeness of testing for the BCR-ABL gene and availability of outpatient treatment with TKIs and associated characteristics.

A total of 685 cases of CML were identified; 55 percent (374) had a documented BCR-ABL gene test with 96 percent (360) of these being positive for the BCR-ABL gene and the remaining 4 percent (14) either testing negative or having a missing result. Registries were able to identify the use of TKIs in 54 percent (369) of patients, though only 43 percent (296) had a corresponding BCR-ABL gene test documented. One state registry reported a significantly lower percentage of patients being tested for the BCR-ABL gene (25 percent) and receiving TKI treatment (21 percent). Limiting analysis to CML case reports from the remaining 9 comparative effectiveness research registries, 78 percent (305) patients had a documented BCR-ABL gene test and 79 percent (308) had documented treatment with a TKI. Receipt of testing or treatment for these 9 states did not vary by sex, race, ethnicity, census tract poverty level, census tract urbanization, or insurance status; BCR-ABL testing varied by state of residence, and BCR-ABL testing and TKI therapy occurred less often with increasing age (BCR-ABL testing: odds ratio [OR], 0.97; 95 percent CI, 0.95-0.99; and TKI therapy: OR, 0.97; 95 percent CI, 0.96-0.99).

Collection of detailed CML data vary significantly by states. A majority of the case patients had appropriate testing for the BCR-ABL gene and treatment with tyrosine kinase inhibitors. However, BCR-ABL testing and TKI treatment decreased with increasing age. Further research is needed to understand CML coding, testing, and treatment disparities.