What is the management of malignant melanoma of the vault?

Management of Malignant Melanoma of the Vault

The management of malignant melanoma of the vault requires wide surgical excision with appropriate margins as the primary treatment, followed by sentinel lymph node biopsy for tumors >1mm thick, and consideration of adjuvant therapy based on staging. 1

Diagnosis

Proper diagnosis is the first step in management and includes:

• Clinical assessment using the ABCDE rule (Asymmetry, Border irregularities, Color heterogeneity, Diameter >6mm, and Evolution) 1
• Full thickness excisional biopsy with 2mm margin of normal skin 1
• Histopathological examination by an experienced pathologist, reporting:
  • Maximum thickness (Breslow)
  • Level of invasion (Clark I-V)
  • Presence of ulceration
  • Presence and extent of regression
  • Clearance of surgical margins 1

Staging and Risk Assessment

Complete staging is essential for treatment planning:

• Physical examination with attention to tumor satellites, in-transit metastases, and regional lymph nodes 1
• Basic laboratory tests: blood count, LDH, alkaline phosphatase 1
• Imaging studies based on tumor thickness:
  • For melanomas <1mm thick: no additional imaging required
  • For melanomas >1mm or suspicious findings: sonography of regional lymph nodes and abdomen
  • For higher stages: chest/abdomen/pelvis imaging 1
  • PET scanning is not useful for initial staging of clinically localized melanoma 1

Treatment Algorithm

1. Primary Tumor Management

• Surgical excision with margins based on tumor thickness:
  • In situ melanoma: 0.5 cm margin
  • Tumors up to 2 mm thick: 1 cm margin
  • Tumors >2 mm thick: 2 cm margin 1
  • Modifications may be needed for preservation of function in anatomically sensitive areas 1

2. Regional Lymph Node Management

• Sentinel lymph node biopsy (SLNB):

  • Recommended for melanomas >1 mm thick
  • Provides accurate staging information
  • Should be performed by skilled teams in experienced centers 1
  • If SLNB is positive, complete lymph node dissection should be considered 1

• Routine elective lymphadenectomy or elective irradiation to regional lymph nodes is not recommended 1

3. Management of Locoregional Metastatic Disease

• Complete surgical removal of positive regional lymph nodes, including the surrounding lymph node region 1
• For isolated metastasis in parenchymal organs, surgical removal is recommended 1
• Before aggressive local surgical treatments, detailed staging with CT or PET scans is necessary to exclude further metastases 1
• For non-resectable transit metastases:
  • Isolated limb perfusion using melphalan and tumor necrosis factor (in experienced centers) 1
  • Radiation therapy as an alternative 1

4. Adjuvant Therapy

• Interferon therapy:

  • Several trials using intermediate dose or pegylated interferon have shown positive effects on disease-free and distant metastases-free survival in patients with micrometastases 1
  • High-dose interferon has shown significant prolongation of disease-free survival but not overall survival 1
  • Consider the toxicity profile when recommending interferon therapy 1

• Immunotherapy:

  • For adjuvant treatment of melanoma with pathologic involvement of regional lymph nodes >1 mm who have undergone complete resection, ipilimumab may be considered 2
  • Dosage: 3 mg/kg every 3 weeks for 4 doses, followed by 3 mg/kg every 12 weeks for up to 4 additional doses 2

• Not recommended: Adjuvant chemotherapy, mistletoe extracts, viscum album, and hormone therapies 1

5. Management of Systemic Metastatic Disease

• Patients should preferentially be treated in controlled clinical trials evaluating new approaches 1
• Surgery of visceral metastases may be appropriate for selected cases with good performance status and isolated tumor manifestation 1
• Palliative radiotherapy for symptomatic brain or localized bone metastases 1
• Systemic therapy options:
  • Single-agent chemotherapy (dacarbazine, temozolomide) for palliative purposes 1
  • Immunotherapy with ipilimumab alone or in combination with nivolumab for unresectable or metastatic melanoma 2

Follow-up

• Regular clinical monitoring to detect relapse and recognize additional skin tumors
• Frequency based on risk of relapse:
  • Every 3-6 months during the first 3 years
  • Every 6-12 months thereafter 1
• For thin primary melanomas: imaging techniques not necessary
• For high-risk patients: consider ultrasound of lymph nodes, CT or PET/PET-CT scans 1
• Patient education on sun protection and regular self-examination 1

Important Caveats and Pitfalls

1. Delayed diagnosis: Early diagnosis is crucial for improved survival. Any suspicious pigmented lesion should be promptly biopsied.

2. Inadequate surgical margins: Ensure appropriate margins based on tumor thickness to reduce local recurrence.

3. Overlooking sentinel lymph node biopsy: SLNB provides critical staging information for melanomas >1mm thick and should not be omitted.

4. Incomplete staging: Thorough staging is essential before planning treatment, especially before aggressive surgical interventions.

5. Neglecting follow-up: Regular follow-up is crucial as 8% of melanoma patients develop a secondary melanoma within 2 years of initial diagnosis 1.

6. Failure to counsel patients: Patients must be educated about sun protection, self-examination, and increased risk for family members 1.