What is the prognosis for in situ and superficially invasive melanoma with a Breslow thickness of 0.2 millimeters (mm)?

From the Guidelines

For in situ and superficially invasive melanoma with a Breslow thickness of 0.2mm, the recommended treatment is wide local excision with a 0.5-1cm margin, as this approach is associated with a reduced risk of local recurrence and excellent prognosis, with a 5-year survival rate exceeding 95%. This recommendation is based on the guidelines of care for the management of primary cutaneous melanoma, which suggest that surgical margins for melanoma in situ should be 0.5- to 1.0-cm margins 1. The choice of surgical margin is critical in balancing the risk of local recurrence with the need to preserve function and cosmesis.

Key Considerations

• The American Academy of Dermatology recommends wide excision with 0.5- to 1.0-cm margins for melanoma in situ, and Mohs micrographic surgery or staged excision with paraffin-embedded permanent sections may be utilized for tissue-sparing excision and exhaustive histologic assessment of peripheral margins 1.
• Sentinel lymph node biopsy is not routinely indicated for melanomas less than 0.8mm thick unless there are concerning features like ulceration or high mitotic rate.
• Regular follow-up examinations are necessary, typically every 3-6 months for the first two years, then every 6-12 months for years 3-5, and annually thereafter.
• Self-skin examinations should be performed monthly, and comprehensive skin examinations by a dermatologist are recommended at least annually.
• Sun protection is crucial for prevention of future skin cancers, including daily use of broad-spectrum sunscreen (SPF 30+), wearing protective clothing, and avoiding peak sun hours.

Evidence-Based Recommendation

The recommendation for a 0.5-1cm margin is based on the most recent and highest quality study available, which suggests that this approach is associated with excellent prognosis and limited potential for metastasis 1. While other studies may suggest different margin widths, the guidelines of care for the management of primary cutaneous melanoma provide a comprehensive and evidence-based approach to the treatment of melanoma in situ.

Clinical Implications

The choice of surgical margin and treatment approach should be individualized based on tumor location, thickness, and other factors, as well as patient preferences and values. However, the recommended treatment of wide local excision with a 0.5-1cm margin remains the standard of care for in situ and superficially invasive melanoma with a Breslow thickness of 0.2mm, as it is associated with excellent prognosis and limited potential for metastasis 1.

From the Research

In Situ and Superficially Invasive Melanoma

• Breslow thickness of 0.2mm is considered a superficially invasive melanoma.
• According to the study 2, the recommended excision margin for invasive melanoma (pT1) ≤ 1.0 mm thick is 1 cm.
• The study 2 also states that melanoma in situ should be excised with 5-10 mm margins, with the aim of achieving complete histological clearance.
• There is no specific guideline for a Breslow thickness of 0.2mm, but it can be inferred that a 1 cm margin may be sufficient, as it is recommended for melanomas up to 1.0 mm thick.

Management of Invasive Melanoma

• The management of invasive melanoma involves surgical excision of the melanoma with a safety margin of surrounding skin and subcutaneous tissue 2.
• The Breslow thickness of the primary melanoma remains the greatest predictor of outcome, and ulceration is associated with a poorer prognosis 3.
• Sentinel lymph node biopsy should be discussed for melanomas ≥ 1 mm thickness (≥ 0.8 mm if other high risk features) 2.
• Imaging is largely used when metastases are suspected on the basis of clinical symptoms or signs 3.

Surgical Excision Margins

• The study 4 found that there is no significant difference in 10-year all-cause mortality between narrow (2 cm) and wide (4 cm) margins for cutaneous melanomas thicker than 2 mm.
• However, this study may not be directly applicable to a Breslow thickness of 0.2mm, as it focuses on melanomas thicker than 2 mm.
• The study 2 recommends a 1 cm margin for invasive melanoma (pT1) ≤ 1.0 mm thick, which may be relevant for a Breslow thickness of 0.2mm.