In this situation, I would personally wait to see how the patient tolerates the first cycle of chemotherapy before starting the TKI. I would consider initiating the TKI after recovery from the nadir of the first cycle.

The published experience is scarce. I like the plan: imatinib (ELTS RISK?) to complete and stable hematological response (when the risk of subsequent cytopenia is perceived to be reduced to ‘zero’’) followed by surgery > dose dense ACT.

Imatinib continued? Yes, in my past experience continuing imatinib during CHT was generally free of additional safety and clinical issues - I remember at least 3 cases similar to the present one.

Switching to Dasatinib at the end of treatment: I would consider this only if the response to and tolerability of imatinib are not optimal. Dasatinib is (considered) a strong immune-suppressant drug - acknowledged, more in vitro than proved in vivo - and knowing the relevance of immune response in breast cancer, an additional discussion point at the time of switching will be considered.

Hope this comment will contribute to finalize / improve the case discussion.

53 year old female diagnosed with CP-CML (WBC: 200,000 and Hb 8) and stage II breast cancer at same time. 
Standard treatment: Dose dense Neoadjuvant AC/T followed by surgery followed by hormonal. 

Given high count: Plan: Imatinib-->Surgery-->Dose dense ACT with G-CSF. Continue imatinib through all treatment. Consider switching to dasatinib after completion of therapy. 

Thoughts?