What are the NCCN (National Comprehensive Cancer Network) guidelines for the treatment of soft tissue sarcoma?

NCCN Guidelines for Soft Tissue Sarcoma Management

The management of soft tissue sarcomas requires evaluation and treatment by a multidisciplinary team with demonstrated expertise in sarcoma management, as recommended by the National Comprehensive Cancer Network (NCCN) guidelines. 1

Overview and Classification

Soft tissue sarcomas (STS) are rare tumors of mesenchymal origin accounting for approximately 1% of adult malignancies and 15% of pediatric malignancies. The NCCN guidelines classify STS into several categories:

• STS of extremity, superficial/trunk, or head and neck
• Retroperitoneal or intra-abdominal STS
• Desmoid tumors (aggressive fibromatoses)
• Rhabdomyosarcoma 1

Diagnosis and Evaluation

Initial Workup

• Thorough history and physical examination
• Appropriate imaging studies:
  • CT is preferred for retroperitoneal/intra-abdominal STS
  • MRI may be used in certain situations
  • Chest imaging for histologies with potential for lung metastases 1, 2

Biopsy

• Core needle biopsy is preferred for diagnosis and grading
• Open incisional biopsy may be considered when necessary
• Fine-needle aspiration alone is discouraged due to limited specimen size 2

Pathologic Assessment

• Diagnosis using WHO Classification of Soft Tissue Tumors
• Assessment should include:
  • Organ and site of sarcoma
  • Depth and size of tumor
  • Histologic grade
  • Presence/absence of necrosis
  • Status of excision margins and lymph nodes
  • TNM stage 2
• Molecular testing for subtypes with characteristic genetic aberrations 2

Treatment Recommendations

Localized Disease

1. Surgery:

   • Complete surgical resection is the primary treatment
   • Wide excision with negative margins is the goal
   • Avoid wide undermining prior to confirmation of clear margins 1

2. Radiation Therapy:

   • Post-operative radiotherapy is standard for high-grade limb sarcomas
   • Consider pre-operative treatment for borderline resectable tumors
   • When margins are negative after PDEMA (Mohs), RT is not recommended 1
   • When PDEMA is not utilized, consider RT if margins are narrow 1

3. Chemotherapy:

   • Not routinely recommended in the adjuvant setting
   • May be considered in specific situations (high-grade, large, deep tumors) 1

Advanced/Metastatic Disease

1. Chemotherapy:

   • Single-agent doxorubicin is standard first-line therapy
   • Ifosfamide is an alternative if anthracyclines are contraindicated
   • Second-line agents include ifosfamide, dacarbazine, trabectedin, and gemcitabine+docetaxel 1

2. Surgical Management:

   • Consider surgical resection of local recurrence and pulmonary metastases in selected patients 1

3. Recurrent Disease:

   • Re-resection if feasible (preferred)
   • RT if not given previously and resection is not feasible 1

Special Considerations

Retroperitoneal/Intra-abdominal STS

• Requires specialized imaging and surgical expertise
• Higher risk of local recurrence compared to extremity STS 1

Dermatofibrosarcoma Protuberans (DFSP)

• Mohs or other forms of PDEMA (peripheral and deep en face margin assessment) are preferred
• Follow-up every 6-12 months with focus on primary site
• Rebiopsy any suspicious regions 1

Follow-up and Surveillance

• Regular follow-up to assess local control and development of metastatic disease
• For DFSP: clinical follow-up every 6-12 months 1
• For other STS: follow-up schedule based on risk of recurrence and metastasis 1

Common Pitfalls to Avoid

• Misdiagnosis of STS as benign lesions
• Inadequate biopsy sampling
• Inappropriate biopsy techniques
• Failure to refer to centers with sarcoma expertise
• Inadequate pathology review 2

The NCCN Guidelines emphasize that adherence to evidence-based recommendations is particularly important for STS due to its rarity and complexity. Analysis of data from the National Cancer Database showed that NCCN Guidelines-adherent treatment was associated with improved survival outcomes. 1