What is the mortality rate for Acute Myeloid Leukemia (AML) blast crisis?

Mortality Rate of AML Blast Crisis

The mortality rate for AML blast crisis is extremely high, with long-term survival observed in only 9% to 22% of patients even with allogeneic hematopoietic stem cell transplantation (HCT) in the setting of active disease. 1

Survival Rates by Patient Population and Treatment

Younger Adults (16-49 years)

• Second complete remission (CR2) can be achieved in approximately 55% of younger adults with intensive salvage therapy who haven't had prior allogeneic HCT
• About two-thirds of these patients can proceed to allogeneic HCT in CR2
• This results in a 40% 5-year overall survival (OS) in this specific subgroup 1

Unselected Adult Population

• Response rates to salvage therapy are significantly lower (20-30%) in more general adult populations with relapsed/refractory AML
• Even with allogeneic HCT in the presence of active disease, CR2 is achieved in only 42% of cases
• Long-term survival ranges from 9% to 22% in this scenario 1

Older Patients

• Outcomes are particularly poor in older patients not eligible for intensive chemotherapy
• Median overall survival with low-dose cytarabine (LDAC) is only 5-6 months 1
• With hypomethylating agents (HMA):
  • Decitabine: median OS of 7.7 months (vs 5.0 months with LDAC)
  • Azacitidine: median OS of 10.4 months (vs 6.5 months with conventional care) 1

Factors Affecting Mortality

Disease-Related Factors

• Cytogenetic profile: Azacitidine may be particularly advantageous in AML with adverse cytogenetics 1
• Blast percentage: Patients with 20-29% blasts have similar outcomes to those with <20% blasts and better outcomes than those with ≥30% blasts, particularly in older patients 2
• Hyperleukocytosis (WBC >100 × 10^9/L): Increases risk of early mortality due to leukostasis, tumor lysis syndrome, and CNS hemorrhage 3

Patient-Related Factors

• Age: Significantly impacts survival with hazard ratios of 1.81 for ages 60-69 and 2.68 for ages ≥70 2
• Comorbidities: Various scoring systems are available to assess patient-specific factors that impact treatment tolerance and outcomes 1

Treatment-Related Factors

• Response to initial therapy: Patients without response after 3 courses of hypomethylating agents are unlikely to respond with further therapy 1
• Access to allogeneic HCT: This remains the only potentially curative option for many patients with relapsed/refractory AML

Special Considerations

Therapy-Related AML (t-AML)

• t-AML has particularly poor outcomes with conventional chemotherapy
• Allogeneic HCT should be considered due to poor results with conventional approaches 1
• t-AML is often associated with more adverse genetic lesions, including TP53 mutations (in 33-36% of cases) 1

Chronic Myeloid Leukemia (CML) Blast Crisis

• Historically, blast crisis in CML had extremely poor outcomes with median survival of only 13 weeks despite intensive chemotherapy 4
• Modern tyrosine kinase inhibitors have improved outcomes, but high-risk additional chromosomal abnormalities at low blast counts still herald poor prognosis 5

Management Implications

• Clinical trials should be prioritized for patients with relapsed/refractory AML whenever possible 1
• For patients not eligible for clinical trials, salvage regimens should be selected based on patient fitness for intensive therapy 1
• Allogeneic HCT should be considered in eligible patients, as it provides the best chance for long-term survival 1
• Supportive care and quality of life considerations are paramount, especially in patients unlikely to achieve long-term survival 1

In summary, AML blast crisis carries a grave prognosis with high mortality rates. The best outcomes are seen in younger patients who achieve a second complete remission and proceed to allogeneic HCT, but even in this optimal scenario, long-term survival remains limited.