Radiation Oncology/Sarcoma/Fibrosarcoma

Fibrosarcoma Benign Fibrous Histologies Nodular fasciitis: rapid growth over several weeks, pain, tenderness. Plump mature fibroblasts. Self-limiting process; recurrence uncommon after excision Fibroma: nonspecific term. Dense fibrous nodule. Simple excision Elastofibroma: rare, slow-growing benign tumor. Typically lower portion of the scapula. Repetitive manual tasks. Considered reactive lesions. Swollen eosinophilic collagen and elastic fibers. Simple excision Superficial fibromatosis: arise from fascia or aponeuroses, small and slow growing Palmar fibromatosis (Dupuytren's contracture) most common Penile fibromatosis (Peyronie's disease) relatively rare, though more common in men who have palmar fibromatosis Deep fibromatosis: clinically diverse, deep-seated fibrous neoplasms For more detail, please see the Desmoid tumor page Fibrosarcoma Epidemiology 2-6% of primary malignant bone lesions Arise most commonly in tubular long bones, usually femur or tibia Most patients are 30-70; equal men and women Predisposing factors (~30% cases) include Paget's, fibrous dysplasia, osteomyelitis, bone infarcts, bone cysts, benign giant cell tumors, desmoplastic fibromas, or previous RT treatment Natural History Locally aggressive Metastatic potential related to grade High grade similar to osteosarcoma: 5-year OS ~25% Low grade: 5-year (and 10-year) OS ~50%. Mets rate 5-15% Survival: 5-year 34%, 10-year 28%, 20-year 25% Children have relatively milder prognosis Diagnosis Lytic with no reactive sclerosis High grade lesions show cortical destruction and periosteal reaction; sometimes with soft-tissue mass Radiographically very similar to osteosarcoma Staging Please see the bone staging page Treatment Overview Aggressive surgical resection Not considered highly radiosensitive, but RT recommended for inoperable tumors, residual disease, and palliation Perez (4th ed) recommends doses 66-70Gy with shrinking-field technique