What is the treatment for pleomorphic dermal sarcoma?

Treatment of Pleomorphic Dermal Sarcoma

Wide surgical excision with negative margins is the primary treatment for pleomorphic dermal sarcoma, with consideration of adjuvant radiotherapy for tumors with adverse features or where wide excision is not possible. 1

Diagnosis and Initial Management

• Preoperative core/punch biopsy is essential to secure diagnosis before definitive treatment
• Pleomorphic dermal sarcoma (PDS) is considered a more aggressive variant of atypical fibroxanthoma (AFX) with adverse pathological features:
  • Deep subcutis invasion
  • Tumor necrosis
  • Lymphovascular invasion
  • Perineural invasion

Surgical Management

Primary Approach

• Wide surgical excision with negative margins is the standard treatment 1
• Surgical margins of ≥2 cm are associated with improved prognosis 2
• Modified Mohs micrographic surgery (M-MMS) has shown better local disease control (83%) compared to conventional surgery (65%) 3

Special Considerations

• For tumors in anatomically challenging locations (e.g., scalp), surgical planning must account for:
  • Potential need for adjuvant radiotherapy
  • Appropriate reconstructive procedures that can tolerate radiation 1
• Surgical margins should be documented by both surgeon and pathologist

Adjuvant Therapy

Radiotherapy

• Adjuvant radiotherapy should be considered in cases where:
  • Wide excision is not possible (e.g., critical anatomical sites)
  • Surgical resection is incomplete and re-excision not possible 1
  • Tumors have adverse pathological features
• Radiotherapy planning should be integrated into the initial surgical approach

Systemic Therapy

• Metastatic PDS can be treated similarly to other soft tissue sarcomas
• Emerging evidence suggests potential benefit from immune checkpoint inhibitors for metastatic disease 1

Management Algorithm

1. Diagnosis:

   • Core/punch biopsy to confirm diagnosis (preferred over diagnostic excision)
   • MRI to determine extent of disease if deep invasion suspected

2. Treatment Planning:

   • Case discussion at specialist sarcoma multidisciplinary team (MDT) meeting
   • Joint management between skin cancer MDT and sarcoma MDT is recommended 1

3. Primary Treatment:

   • Wide surgical excision with ≥2 cm margins when feasible
   • Consider M-MMS for improved local control, especially in anatomically sensitive areas

4. Adjuvant Therapy:

   • Radiotherapy for:
     • Incomplete resection where re-excision not possible
     • Tumors with adverse features in high-risk locations
     • Cases where adequate margins cannot be achieved

5. Follow-up:

   • Close monitoring due to risk of local recurrence (up to 28%) and metastasis (up to 20%) 2
   • More intensive surveillance for tumors with adverse pathological features

Prognostic Factors and Outcomes

• Local recurrence rates: 17-35% depending on surgical approach 3
• Metastasis rates: approximately 12% overall 3
• Risk factors for recurrence:
  • Surgical margins <2 cm 2
  • Absence of ulceration (interestingly, ulcerated tumors have better prognosis) 2
  • Inadequate deep margins 4

Pitfalls and Caveats

• PDS is more aggressive than previously estimated, with higher metastatic potential than AFX
• Diagnostic confusion with other spindle cell tumors can lead to inadequate treatment
• Scalp is the most common location (63-76% of cases) and requires special attention to reconstruction 4, 5
• Elderly males are predominantly affected, which may influence treatment decisions regarding extensive surgery and adjuvant therapy