Courtesy: Prof Robert Ashford, President, British Orthopaedic Oncology Society

 

Principles of Treating Soft Tissue Sarcomas

Overview

Soft tissue sarcomas are rare malignant tumors arising from mesenchymal tissues such as:

• Muscle
• Fat
• Fibrous tissue
• Blood vessels
• Peripheral nerves

They are biologically heterogeneous tumors with varying:

• Aggressiveness
• Local recurrence risk
• Metastatic potential
• Response to treatment

Most patients present with a painless soft tissue mass.

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Epidemiology

• Sarcomas account for approximately 1.4% of all new cancers
• About 90% arise from soft tissues
• Incidence: approximately 20–30 cases per million annually
• Overall 5-year survival: around 55%
• Can occur at any age and at any anatomical site

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Clinical Features Suggesting Malignancy

Features raising suspicion for sarcoma include:

• Size >5 cm
• Deep location beneath fascia
• Rapid increase in size
• Painful mass
• Recurrence after previous excision
• Calcification or bone erosion on X-ray
• Change in size over time

Most sarcomas initially present as a painless lump mistaken for benign lesions such as:

• Lipoma
• Hematoma

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Classification

Soft tissue sarcomas are classified based on:

• Histological subtype
• Tumor differentiation
• Molecular characteristics

More than 100 histological subtypes exist.

Common examples:

• Undifferentiated pleomorphic sarcoma
• Liposarcoma
• Synovial sarcoma
• Rhabdomyosarcoma

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Etiology and Risk Factors

Recognized risk factors include:

Environmental

• Prior radiation exposure
• Certain chemical exposures

Genetic Syndromes

• Neurofibromatosis
• Li–Fraumeni syndrome
• Hereditary retinoblastoma

Viral Associations

Particularly in immunocompromised patients:

• Epstein–Barr virus
• Human herpesvirus 8

There is no strong evidence linking:

• Trauma
• Orthopedic implants

to sarcoma development.

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Imaging Evaluation

1. Ultrasound

• Often initial investigation
• Operator dependent

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2. MRI (Most Important)

MRI is the imaging modality of choice for extremity soft tissue sarcomas.

Advantages:

• Defines local extent
• Evaluates neurovascular involvement
• Assesses compartment involvement
• Helps biopsy planning

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3. CT Scan

Useful for:

• Retroperitoneal sarcomas
• Metastatic staging
• Pulmonary metastasis detection

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4. PET-CT

May help in:

• Detecting recurrence
• Guiding biopsy
• Assessing metastatic disease

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Biopsy Principles

Golden Rule

Biopsy should be carefully planned because poorly placed biopsy tracts can compromise future limb-sparing surgery.

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Preferred Method

Core Needle Biopsy

• Image-guided
• Standard technique
• Minimally invasive

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Excision Biopsy

May be considered only for:

• Small
• Superficial lesions

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Open Biopsy Principles

• Longitudinal incision
• Minimal tissue contamination
• Avoid neurovascular injury
• Include tumor-normal tissue interface

Frozen section is mainly used to confirm:

• Adequate tissue sampling

rather than establish final diagnosis.

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Staging and Grading

Staging is based on:

• Tumor size
• Nodal involvement
• Metastasis

Important concepts:

• Larger tumors have worse prognosis
• Approximately one-third are low-grade
• Remaining tumors are high-grade

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Prognostic Factors

Poor prognostic indicators include:

• Metastasis at presentation
• Large tumor size
• Deep location
• Older age
• Positive surgical margins
• Elevated inflammatory markers

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Multidisciplinary Management

Management requires coordination among:

• Orthopedic oncologists
• Radiologists
• Pathologists
• Medical oncologists
• Radiation oncologists
• Plastic surgeons
• Specialist nurses

Treatment plans should distinguish:

• Curative intent
• Palliative intent

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Surgical Management

Most Important Treatment

Surgery remains the most effective curative treatment.

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Limb Salvage

Preferred whenever feasible.

Amputation is now uncommon.

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Surgical Principles

• Achieve wide excision margins
• Avoid tumor contamination
• Preserve limb function where possible
• Plan reconstruction carefully

Most procedures involve:

• Wide local excision

rather than radical compartmental resections.

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Surgical Margins

Adequate margins are essential for:

• Local control
• Reduced recurrence risk

Important concept:

• Planned positive margins are preferable to unplanned incomplete excisions.

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Reconstruction

Large resections may require:

• Skin grafts
• Muscle flaps
• Free tissue transfer

Plastic surgical collaboration is often necessary.

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Radiotherapy

Radiotherapy may be used:

• Preoperatively
• Postoperatively
• Occasionally as primary treatment

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Preoperative Radiotherapy

Advantages:

• Better target definition
• Smaller radiation field

Disadvantage:

• Increased wound complications

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Postoperative Radiotherapy

Advantages:

• Final pathology available before treatment

Disadvantages:

• Increased fibrosis
• Joint stiffness
• Fracture risk

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Chemotherapy

Usually reserved for:

• Advanced disease
• Metastatic disease
• Specific chemosensitive subtypes

Responsive tumors include:

• Rhabdomyosarcoma
• Synovial sarcoma

Common regimens:

• Anthracycline-based chemotherapy
• Ifosfamide combinations

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Metastatic Disease

Most Common Site

• Lung metastasis

Median survival after metastasis:

• Less than one year

Selected patients with isolated pulmonary metastases may benefit from:

• Pulmonary metastasectomy

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Key Orthopedic Oncology Principles

• Suspect sarcoma in enlarging deep soft tissue masses
• Any mass >5 cm requires careful evaluation
• MRI before biopsy whenever possible
• Biopsy must follow oncologic principles
• Surgery with adequate margins is critical
• Multidisciplinary care improves outcomes
• Long-term follow-up is essential for recurrence detection