C92.12

Chronic myeloid leukemia, BCR-ABL positive, in relapse

## Overview of Chronic Myeloid Leukemia, BCR-ABL positive, in relapseChronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm characterized by the excessive and uncontrolled proliferation of myeloid cells in the bone marrow and peripheral blood. The hallmark of CML is the Philadelphia chromosome (Ph), a reciprocal translocation between chromosomes 9 and 22, t(9;22)(q34;q11), which results in the formation of the BCR-ABL1 fusion gene. This gene encodes a constitutively active tyrosine kinase (BCR-ABL1 TKI), which drives the uncontrolled cell growth and survival characteristic of the disease. ### Pathophysiology In CML, the BCR-ABL1 fusion protein dysregulates numerous signaling pathways involved in cell proliferation, differentiation, and apoptosis. The protein acts as a constitutively active tyrosine kinase, leading to activation of downstream pathways such as RAS/MAPK, PI3K/AKT, and JAK/STAT. This results in an increased proliferation of granulocytic precursors, reduced apoptosis, and altered adhesion properties of hematopoietic stem cells, causing them to be released into the peripheral circulation. CML typically progresses through three phases: chronic phase (CP), accelerated phase (AP), and blast phase (BP). Relapse refers to the re-emergence of disease activity after a period of remission or stable disease, particularly in patients who initially responded to tyrosine kinase inhibitor (TKI) therapy. The primary mechanism of relapse in BCR-ABL1 positive CML is the development of resistance to TKIs. This resistance can be primary (lack of initial response) or acquired (loss of response after an initial period of effectiveness). Acquired resistance is frequently mediated by mutations within the BCR-ABL1 kinase domain, which reduce the binding affinity of the TKI. The most common and clinically significant mutation is T315I, which confers resistance to most first- and second-generation TKIs. Other mechanisms include amplification of the BCR-ABL1 gene, activation of alternative signaling pathways, or poor drug adherence by the patient. ### Clinical Presentation Patients in CML relapse, particularly from a molecular or cytogenetic remission, may present with a recurrence of symptoms. These can include generalized fatigue, unintentional weight loss, night sweats, low-grade fever, and abdominal fullness or discomfort due to splenomegaly. Hematological parameters often show a rising white blood cell (WBC) count, often with an increase in immature myeloid forms (myelocytes, metamyelocytes, promyelocytes) in the peripheral blood. Anemia and thrombocytopenia may also develop or worsen. Bone pain may indicate increased marrow activity or infiltration. The presentation can vary depending on the depth of the prior remission and the speed of disease re-emergence. ### Diagnostic Criteria for Relapse Diagnosis of CML relapse relies heavily on molecular and cytogenetic monitoring. Patients receiving TKI therapy are regularly monitored for BCR-ABL1 transcript levels using quantitative real-time polymerase chain reaction (qRT-PCR). Relapse is typically defined by a loss of major molecular response (MMR), which is a 3-log reduction in BCR-ABL1 transcripts from a standardized baseline (BCR-ABL1/ABL ratio ≤0.1% on the International Scale [IS]), or loss of complete molecular response (CMR, undetectable BCR-ABL1). Cytogenetic relapse is indicated by the reappearance of the Philadelphia chromosome (Ph+) in bone marrow metaphases. Hematologic relapse is characterized by an increase in WBC count, presence of immature myeloid cells, and worsening splenomegaly. Bone marrow biopsy and aspiration are performed to assess cellularity, myeloid-to-erythroid ratio, fibrosis, and the percentage of blasts, which helps differentiate relapse from progression to accelerated or blast phase. ### Standard of Care The management of CML in relapse, particularly after TKI failure, depends on the specific cause of resistance and prior treatment history. If a BCR-ABL1 kinase domain mutation is identified, switching to a TKI specifically active against that mutation is the preferred strategy (e.g., ponatinib or asciminib for T315I mutation). For patients who fail multiple TKIs or progress to advanced phases (accelerated or blast phase) despite optimal TKI therapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a potentially curative option. Regular monitoring of BCR-ABL1 levels, mutation analysis, and adherence counseling are crucial components of ongoing management. Supportive care includes managing symptoms, transfusions for anemia or thrombocytopenia, and infection prophylaxis.

Clinical Symptoms

  • Fatigue
  • Unintentional weight loss
  • Night sweats
  • Low-grade fever
  • Abdominal fullness
  • Splenomegaly
  • Bone pain
  • Increased white blood cell count
  • Anemia
  • Thrombocytopenia
  • Easy bruising or bleeding
  • Shortness of breath
  • Recurrent infections
  • Increased immature myeloid cells in blood

Common Causes

  • BCR-ABL1 fusion gene (Philadelphia chromosome) (underlying cause)
  • Development of BCR-ABL1 kinase domain mutations (e.g., T315I) conferring TKI resistance
  • Amplification of the BCR-ABL1 gene
  • Activation of alternative signaling pathways bypassing TKI inhibition
  • Poor patient adherence to tyrosine kinase inhibitor (TKI) therapy
  • Clonal evolution leading to TKI insensitivity
  • Inadequate TKI dosing or suboptimal TKI choice

Documentation & Coding Tips

Clearly document the patient's CML relapse status, specifically mentioning 'BCR-ABL positive' and the current phase of relapse (e.g., chronic, accelerated, blastic). Avoid ambiguous terms.

Example: PLAN: Patient with known Chronic Myeloid Leukemia (CML), BCR-ABL positive, now clearly documented in accelerated phase relapse, confirmed by repeat FISH and quantitative PCR showing rising BCR-ABL transcript levels (IS >1%). Initiating second-line TKI therapy. Note: Prior treatment with Imatinib failed due to resistance, consistent with current relapse. Patient's chronic conditions (CKD Stage III, Type 2 DM with neuropathy) are stable but monitored closely due to potential drug interactions and increased complexity of care. This impacts HCC RAF for higher payment and resource allocation.

Billing Focus: Specificity of CML type (BCR-ABL positive), explicit statement of 'in relapse' and current phase (accelerated), documentation of prior treatment failure.

Detail the evidence supporting the relapse, including specific molecular and hematological findings (e.g., rising WBC, blast count, increasing BCR-ABL transcript levels, cytogenetic changes).

Example: ASSESSMENT: 62 Y/O M with CML, BCR-ABL positive, in chronic phase relapse. Patient presents with fatigue and splenomegaly. Labs show WBC 45,000 (baseline 9,000), platelet count 550,000, and 6% blasts in peripheral blood. Quantitative PCR demonstrates BCR-ABL (IS) of 2.5%, up from 0.1% 3 months ago. Bone marrow biopsy results pending. This confirms progression from previous major molecular response to a relapse, necessitating treatment escalation. Patient also has documented stable CAD and essential hypertension, which contribute to the overall risk profile and HCC score.

Billing Focus: Quantifiable metrics (WBC, blast count, BCR-ABL %IS), clinical signs (splenomegaly), and explicit statement of progression/relapse status. Links findings directly to diagnosis.

Document the patient's current treatment regimen, any changes in therapy due to relapse, and the rationale for these changes (e.g., TKI resistance, intolerance).

Example: PLAN: Due to documented relapse of BCR-ABL positive CML while on Dasatinib (previous TKI), patient will be transitioned to Nilotinib 400mg BID. Nilotinib chosen due to known Dasatinib resistance mutation (T315I not identified, but other mutations pending). Educated patient on side effects and monitoring. Baseline ECG and LFTs ordered prior to initiation. Patient's pre-existing chronic hepatitis C (inactive, HCC 141) is a consideration for hepatotoxicity, requiring close monitoring, adding to complexity.

Billing Focus: Specific drug name and dosage, reason for therapy change (relapse, resistance), monitoring requirements, and planned follow-up.

Thoroughly document all signs, symptoms, and complications related to CML relapse, including organomegaly, cytopenias, infections, and constitutional symptoms, linking them explicitly to the diagnosis.

Example: ASSESSMENT: 55 Y/O F with CML, BCR-ABL positive, in blastic phase relapse. Presented to ED with acute onset fever (102.5F), severe fatigue, and left upper quadrant pain. Exam significant for palpable splenomegaly (8cm below costal margin) and sternal tenderness. Labs show Pancytopenia (Hgb 7.2, WBC 1,500, Plt 35,000), confirming bone marrow failure secondary to blastic transformation. Patient is immunocompromised due to disease and therapy, increasing risk of opportunistic infections. History of chronic CHF (HCC 85) complicates fluid management during chemotherapy.

Billing Focus: Detailed clinical manifestations (fever, pain, splenomegaly, sternal tenderness), specific lab abnormalities (pancytopenia), and direct linkage to 'blastic phase relapse'.

Document the type and results of diagnostic procedures performed to confirm relapse (e.g., bone marrow biopsy, cytogenetics, FISH, molecular studies).

Example: DIAGNOSTIC WORKUP: Follow-up bone marrow biopsy performed (CPT 38222) confirmed CML, BCR-ABL positive, in accelerated phase relapse, showing 18% blasts. Cytogenetics revealed a new clonal abnormality (trisomy 8) in addition to the Philadelphia chromosome, indicating disease progression and contributing to the relapse severity. Molecular testing showed increasing BCR-ABL1/ABL ratio (IS 3.2%), confirming molecular relapse. These findings dictate the need for intensified treatment strategy. Patient also has morbid obesity (HCC 22) and OSA, which factor into anesthesia risk for procedures and overall care plan.

Billing Focus: Specific diagnostic tests performed (BMBx, cytogenetics, molecular), quantification of findings (18% blasts, 3.2% IS), and explicit confirmation of relapse and phase.

Relevant CPT Codes

Related Diagnoses

Hierarchy