Sarcoma

Sarcomas are a diverse group of rare cancers that arise from connective tissues, including bone, muscle, fat, blood vessels, nerves, and other supporting tissues. They account for approximately 1% of all adult cancers and 15% of childhood cancers. With over 70 different subtypes, sarcomas can occur anywhere in the body but most commonly develop in the arms, legs, chest, or abdomen. Early detection and specialized treatment are crucial for optimal outcomes.

⚠️ When to Seek Immediate Care

Seek immediate medical attention for: rapidly growing mass, severe bone pain with swelling, pathological fracture (bone breaking with minimal trauma), difficulty breathing from chest mass, or signs of nerve/blood vessel compression. Early evaluation is critical for sarcomas.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment of any medical condition.

Understanding Sarcoma

Sarcomas develop from mesenchymal cells, which form the body's connective tissues. Unlike carcinomas that arise from epithelial cells, sarcomas can occur in bones, muscles, tendons, cartilage, nerves, fat, and blood vessels. Their rarity often leads to delayed diagnosis, making awareness crucial.

Key Statistics

  • Approximately 13,000 new soft tissue sarcomas diagnosed annually in US
  • About 3,500 new bone sarcomas diagnosed yearly
  • Can occur at any age, but patterns vary by type
  • 5-year survival rates range from 15% to 90% depending on type and stage
  • Over 70 different histological subtypes
  • 50% occur in extremities, 40% in trunk/retroperitoneum, 10% head/neck

Types of Sarcoma

Soft Tissue Sarcomas

Common Types

  • Liposarcoma:
    • Arises from fat cells
    • Most common in adults
    • Often in thigh or retroperitoneum
    • Subtypes vary in aggressiveness
  • Leiomyosarcoma:
    • From smooth muscle cells
    • Can occur in uterus, GI tract, blood vessels
    • Often aggressive
  • Synovial sarcoma:
    • Despite name, not from synovial tissue
    • Common in young adults
    • Often near joints
  • Malignant peripheral nerve sheath tumor (MPNST):
    • Arises from nerve sheaths
    • Associated with neurofibromatosis
  • Gastrointestinal stromal tumor (GIST):
    • Most common GI sarcoma
    • KIT or PDGFRA mutations
    • Responds to targeted therapy

Other Soft Tissue Types

  • Fibrosarcoma
  • Rhabdomyosarcoma (common in children)
  • Angiosarcoma (blood vessels)
  • Solitary fibrous tumor
  • Dermatofibrosarcoma protuberans
  • Epithelioid sarcoma
  • Clear cell sarcoma
  • Alveolar soft part sarcoma

Bone Sarcomas

  • Osteosarcoma:
    • Most common primary bone cancer
    • Peak in teenagers and young adults
    • Often in long bones near knee
  • Ewing sarcoma:
    • Second most common in children/young adults
    • Can occur in bones or soft tissue
    • EWSR1 gene fusion
  • Chondrosarcoma:
    • Arises from cartilage
    • More common in adults
    • Often in pelvis, femur, shoulder
  • Chordoma:
    • Rare, from notochord remnants
    • Skull base or spine
    • Slow-growing but locally aggressive

Signs and Symptoms

Soft Tissue Sarcoma Symptoms

  • Most common: Painless lump or mass
  • Size: Often larger than 5 cm at diagnosis
  • Growth: May grow slowly or rapidly
  • Pain: Develops when tumor presses on nerves or muscles
  • Location-specific symptoms:
    • Abdominal: fullness, pain, bowel changes
    • Chest: breathing difficulties, cough
    • Extremity: swelling, limited movement
    • Retroperitoneal: back pain, urinary symptoms

Bone Sarcoma Symptoms

  • Pain:
    • Most common symptom
    • Initially intermittent, becomes constant
    • Worse at night
    • Not relieved by rest
  • Swelling: Develops weeks after pain starts
  • Fracture: Pathological fracture with minimal trauma
  • Decreased mobility: Joint stiffness or limp
  • Constitutional symptoms: Fever, weight loss (less common)

Red Flag Features

  • Mass larger than 5 cm
  • Deep to fascia
  • Rapid growth
  • Firm, fixed mass
  • Recurrence after previous excision
  • Associated neurovascular symptoms

Risk Factors

Genetic Syndromes

  • Li-Fraumeni syndrome: TP53 mutations
  • Hereditary retinoblastoma: RB1 mutations
  • Neurofibromatosis type 1: Risk of MPNST
  • Gardner syndrome: Desmoid tumors
  • Werner syndrome: Various sarcomas
  • Hereditary leiomyomatosis: Leiomyosarcoma risk

Environmental Factors

  • Radiation exposure:
    • Previous radiation therapy
    • Usually 5-30 years latency
    • Risk increases with dose
  • Chemical exposure:
    • Vinyl chloride (angiosarcoma)
    • Dioxin
    • Thorotrast
  • Chronic lymphedema: Risk of angiosarcoma
  • Foreign bodies: Rare cases around implants

Other Risk Factors

  • Paget disease of bone (osteosarcoma risk)
  • Bone infarcts
  • HIV/AIDS (Kaposi sarcoma)
  • Human herpesvirus 8 (Kaposi sarcoma)

Diagnosis

Initial Evaluation

  • Medical history:
    • Symptom duration and progression
    • Prior radiation or chemical exposure
    • Family history of cancer
    • Previous cancers
  • Physical examination:
    • Size and location of mass
    • Mobility vs. fixation
    • Neurovascular status
    • Regional lymph nodes

Imaging Studies

  • For soft tissue masses:
    • MRI with contrast (preferred)
    • Shows tumor extent and relationship to structures
    • CT for retroperitoneal or chest tumors
  • For bone tumors:
    • Plain radiographs first
    • MRI for local staging
    • CT for cortical destruction
  • Staging studies:
    • Chest CT (lung metastases)
    • PET/CT for some types
    • Bone scan for bone sarcomas

Biopsy

  • Core needle biopsy:
    • Preferred for most cases
    • Image-guided
    • Multiple cores needed
  • Incisional biopsy:
    • When core biopsy inadequate
    • Careful planning of incision
  • Excisional biopsy:
    • Only for small (<3cm) superficial lesions
    • Must have clear margins

Pathology

  • Histological examination
  • Immunohistochemistry
  • Molecular testing (translocations, mutations)
  • Grading (low, intermediate, high)

Treatment

Multidisciplinary Approach

Sarcoma treatment requires a specialized team including orthopedic/surgical oncologists, medical oncologists, radiation oncologists, pathologists, and radiologists. Treatment at specialized sarcoma centers improves outcomes.

Surgery

  • Primary treatment for localized disease
  • Goals:
    • Complete resection with negative margins
    • Preserve function when possible
    • Limb-sparing surgery preferred
  • Margin requirements:
    • Wide margins (1-2 cm) for high-grade
    • May be less for low-grade
    • Anatomic barriers acceptable
  • Reconstruction:
    • Soft tissue coverage
    • Bone reconstruction
    • Vascular reconstruction

Radiation Therapy

  • Indications:
    • High-grade tumors
    • Large tumors (>5 cm)
    • Close or positive margins
    • Recurrent disease
  • Timing:
    • Preoperative: May shrink tumor, less dose needed
    • Postoperative: Higher dose, larger field
  • Techniques:
    • External beam (IMRT)
    • Brachytherapy
    • Proton therapy for select cases

Systemic Therapy

Chemotherapy

  • Most sensitive types:
    • Osteosarcoma
    • Ewing sarcoma
    • Rhabdomyosarcoma
    • Some synovial sarcomas
  • Common regimens:
    • Doxorubicin-based
    • Ifosfamide combinations
    • Gemcitabine/docetaxel

Targeted Therapy

  • Imatinib: For GIST with KIT mutations
  • Pazopanib: For advanced soft tissue sarcomas
  • Denosumab: For giant cell tumor of bone
  • Crizotinib: For ALK-rearranged tumors
  • Larotrectinib: For NTRK fusion tumors

Immunotherapy

  • Limited efficacy in most sarcomas
  • Some activity in:
    • Alveolar soft part sarcoma
    • Angiosarcoma
    • Undifferentiated pleomorphic sarcoma
  • Clinical trials ongoing

Follow-up and Monitoring

Surveillance Schedule

  • Years 1-2:
    • Every 3 months
    • Physical exam
    • Imaging of primary site
    • Chest imaging
  • Years 3-5:
    • Every 4-6 months
    • Same assessments
  • After 5 years:
    • Annual evaluation
    • Higher risk may need closer follow-up

Late Effects

  • Secondary malignancies from radiation
  • Cardiac toxicity from doxorubicin
  • Functional limitations
  • Lymphedema
  • Chronic pain
  • Psychological effects

Prognosis

Prognostic Factors

  • Most important:
    • Stage at diagnosis
    • Tumor grade
    • Size (>5 cm worse)
    • Deep location
    • Histologic subtype
  • Treatment factors:
    • Complete surgical resection
    • Negative margins
    • Response to chemotherapy

Survival Rates

  • Localized disease: 60-80% 5-year survival
  • Metastatic disease: 15-30% 5-year survival
  • By grade:
    • Low-grade: 90% 5-year survival
    • High-grade: 50-60% 5-year survival
  • Specific types vary widely:
    • Well-differentiated liposarcoma: >90%
    • Angiosarcoma: 30-40%
    • GIST with targeted therapy: 80-85%

Quality of Life

Modern limb-sparing techniques and reconstruction allow most patients to maintain good function. Rehabilitation, physical therapy, and psychosocial support are important components of survivorship care. Many patients return to normal activities after treatment.