Rhabdomyosarcoma: Subtypes, Treatment, and Prognosis

Overview

Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma arising from skeletal muscle progenitors. Most common soft tissue sarcoma in children; rare in adults.

Major Histologic Subtypes

• Embryonal RMS (~60%): Young children; head/neck, GU tract. Botryoid variant (grape-like) in hollow organs. Better prognosis.
• Alveolar RMS (~20%): Older children/adolescents; extremities, trunk. PAX3/7-FOXO1 fusion. More aggressive.
• Pleomorphic RMS: Adults; deep extremity/trunk. Complex karyotype.
• Spindle cell/sclerosing RMS: Infants (congenital) or adults; specific molecular drivers.

Multimodal Treatment

• Surgery: Complete resection when feasible without functional loss.
• Chemotherapy: VAC (vincristine, actinomycin D, cyclophosphamide) backbone; add irinotecan, ifosfamide, doxorubicin for high-risk.
• Radiation: For residual disease, unresectable, or high-risk sites. Techniques: IMRT, proton therapy to spare growth.

Prognosis

• Overall 5-year survival ~65–70%.
• Low-risk (embryonal, favorable site, resected): >90%.
• High-risk (alveolar, metastatic, unfavorable site): 30–50%.

Follow-Up

Lifelong surveillance for recurrence, second malignancies, and late effects (cardiotoxicity, infertility, growth impairment, neurocognitive).