What is the prognosis of aplastic anemia?

Prognosis of Aplastic Anemia

Without treatment, severe aplastic anemia has a mortality rate approaching 70% within 2 years, but with appropriate therapy, long-term survival rates of 65-79% can be achieved depending on treatment modality and patient factors. 1

Prognostic Factors

• Disease severity is the most significant predictor of survival in aplastic anemia, with moderate aplastic anemia having better outcomes (71% 6-year survival) compared to severe (48% 6-year survival) or very severe disease (38% 6-year survival) 2
• Absolute neutrophil count (ANC) ≤200/mm³ is independently associated with poor survival in patients treated with immunosuppressive therapy 3
• Response to initial immunosuppressive therapy is a critical determinant of long-term outcomes, with responders having significantly better survival than non-responders 2
• Age is an important factor in treatment selection but doesn't independently affect survival within treatment groups 3, 2

Treatment-Based Prognosis

Hematopoietic Stem Cell Transplantation (HSCT)

• For patients younger than 50 years with a matched sibling donor, allogeneic HSCT offers the best chance for cure 1
• Modern HSCT protocols achieve approximately 79% 6-year survival rates 3
• HSCT outcomes have improved over time, with 6-year survival rates increasing from 43% before 1984 to 72% after 1984 2
• Complications affecting prognosis include:
  • Graft failure (occurs in approximately 12.5% of cases) 3
  • Acute graft-versus-host disease (GVHD) grade II-IV (occurs in about 31.3% of patients) 3
  • Chronic GVHD (develops in approximately 18.8% of transplant recipients) 3

Immunosuppressive Therapy (IST)

• First-line IST with horse antithymocyte globulin (ATG) and cyclosporine achieves response rates of approximately 46.8% 3
• The 6-year survival rate with IST is approximately 69% 3
• Relapse occurs in about 7.1% of patients treated with IST 3
• For patients aged 14-40 years treated with IST, the 6-year survival rate (65%) is not statistically different from those receiving BMT (79%), though BMT achieves better long-term engraftment and lower relapse rates 3

Long-Term Complications

• Development of clonal hematologic disorders is a significant concern:
  • Myelodysplastic syndrome (MDS) can develop in patients treated with IST 3
  • Acute myelogenous leukemia (AML) is a potential late complication 3
  • Paroxysmal nocturnal hemoglobinuria (PNH) may develop during the course of the disease 3, 4
• The risk of these clonal complications appears to be approximately 6.5% in patients followed for more than 2 years after ATG treatment 2
• Secondary malignancies including lymphoma and solid tumors have been reported 2

Treatment Selection Impact on Prognosis

• For patients under age 50 with a matched sibling donor, HSCT offers the best long-term prognosis and potential cure 1
• For patients without a suitable donor or those over age 50, IST with equine ATG, cyclosporine A, and eltrombopag is the standard approach 1
• Patients who fail to respond to initial IST may be candidates for alternative donor transplantation 5

Monitoring and Follow-up

• Long-term monitoring is essential due to the risk of relapse and clonal evolution 6
• Regular assessment for the development of MDS, AML, or PNH is necessary during follow-up 3, 2
• Cyclosporine should be administered for at least 6 months to optimize outcomes 5

The prognosis of aplastic anemia has improved dramatically over the past few decades with advances in both HSCT and immunosuppressive regimens, transforming what was once a nearly uniformly fatal disease into a manageable condition with good long-term survival prospects for most patients.