Cytogenetic and fluorescence in situ hybridization testing in veterans with chronic lymphocytic leukemia.

Abstract

7526 Background: The presence of deletion 17p (del17), determined by chromosome analysis and/or fluorescence in situ hybridization (FISH), is a strong negative prognostic marker in chronic lymphocytic leukemia (CLL). Prior to the introduction of novel agents (ibrutinib, venetoclax), the clinical utility of cytogenetics/FISH was limited by the absence of chemoimmunotherapy regimens that were proven effective in patients with del17. Testing practices for chromosomal aberrations since the introduction of novel agents have not been reported. We report cytogenetic/FISH trends in a nationwide cohort of veterans diagnosed with CLL. Methods: CLL patients diagnosed 2008-2015 and receiving care at VA were identified through the VA Clinical Cancer Registry. Electronic medical records were used to determine cytogenetic/FISH testing (lab records), treatment histories (pharmacy dispensation records), and evidence of system use (heme-onc notes). Cytogenetic/FISH testing was identified by presence of specific keywords in the test name or Logical Observation Identifiers Names and Codes (LOINC) descriptions, then validated by human annotation. The testing rates are reported for the entire cohort, at time of diagnosis, time of regimen initiation (including the 12 months preceding initiation), during the novel era (2014 – 2015) and prior (2008–2013). Results: From 2008 to 2015, 3,638 CLL patients were diagnosed and received care at VA. Documented records of treatment regimens were available for 1,562 patients who received a total of 2,929 treatment regimens. Only 24% (998) of patients were tested at any point in time during their care at the VA, 17% (622) were tested at time of diagnosis, and 19% (542) of treatment courses were preceded by cytogenetic/FISH testing. No testing differences existed following the introduction of the novel agents at diagnosis (both ~ 17%), or prior to regimen initiation (20% vs 16%). Conclusions: Our study suggests CLL patients diagnosed and receiving care at the VA are not routinely undergoing cytogenetics/FISH testing at diagnosis or prior to treatment. Changing this practice pattern will personalize treatments so that del17 CLL patients receive less toxic and more effective therapies.