What is the prognosis for rhabdomyosarcoma with metastasis to the kidney, liver, and bone marrow?

Prognosis for Rhabdomyosarcoma with Metastasis to Kidney, Liver, and Bone Marrow

The prognosis for rhabdomyosarcoma with metastasis to kidney, liver, and bone marrow is extremely poor, with 5-year overall survival rates of approximately 10-13% based on the most recent evidence. 1

Prognostic Factors in Metastatic Rhabdomyosarcoma

Disease-Specific Factors

• Metastatic Sites: Multiple metastatic sites (kidney, liver, and bone marrow) represent a particularly unfavorable presentation
  • Bone marrow involvement is especially concerning, with 3-year overall survival of only 26.1% and 5-year survival dropping to 12.6% 1
  • Patients with bone marrow metastasis at diagnosis have a median survival of only 1.5 years 2
  • Multiple bone metastases confer a poorer outcome than lung/pleural metastases (<20% vs 20-40% 5-year survival) 3

Patient-Related Factors

• Age: Age ≥10 years is associated with worse outcomes in metastatic disease 1
• Oberlin Score: An Oberlin score of 4 (which includes bone marrow metastasis) portends a 3-year overall survival of 0% 2

Treatment Considerations and Impact on Prognosis

Despite aggressive multimodal therapy, outcomes remain dismal for widely metastatic rhabdomyosarcoma:

• Systemic Therapy: Standard chemotherapy regimens include combinations of:

  • Doxorubicin, cyclophosphamide, ifosfamide, vincristine, dactinomycin, and etoposide 3
  • Response to chemotherapy is a critical prognostic factor - complete responders have 57% 5-year survival versus only 7% for poor responders 4

• Local Control Measures:

  • Complete surgical resection of primary tumor, where feasible, is preferred 3
  • Radiotherapy should be applied to primary and metastatic sites when possible 3
  • Local control of both primary tumor and metastatic sites is associated with better event-free survival compared to those with partial or no local control 3

Specific Prognostic Indicators

• Histology: Alveolar histology and FOXO1 fusion presence are associated with worse outcomes in metastatic disease 1
• Tumor Size: Tumors >10 cm have 0% 5-year survival rate compared to 60% for tumors <5 cm 4
• Time to Relapse: For relapsed disease, time to relapse is the only identified prognostic factor - patients relapsing later than 2 years from initial diagnosis have better outcomes 3

Clinical Course and Monitoring

Most patients with metastatic rhabdomyosarcoma will initially respond to therapy but will ultimately relapse:

• The majority of relapses occur within the first 3 years of follow-up 3
• Follow-up intervals should be 2-3 months during the first 3 years, 6 months until 5 years, and at least once yearly thereafter 3
• Long-term survivors (>4 years) are extremely rare in cases with bone marrow involvement 2

Emerging Approaches

Given the dismal prognosis with conventional therapy, patients with metastatic rhabdomyosarcoma to bone marrow, liver, and kidney should be considered for:

• Enrollment in clinical trials testing novel agents 1
• High-dose chemotherapy approaches with autologous stem cell rescue (though evidence of benefit is still lacking) 3

Pitfalls in Management

• Misdiagnosis can occur as metastatic rhabdomyosarcoma with bone marrow involvement can present similarly to hematologic malignancies, leading to treatment delays 5
• Incomplete staging may miss the full extent of metastatic disease
• Focusing only on the primary tumor without adequate attention to metastatic sites can worsen outcomes 3