What are the excision margins for a melanoma with a Breslow depth of 2.9mm?

From the Guidelines

For a melanoma with a Breslow depth of 2.9mm, the recommended excision margin is 2 cm. This means that during the surgical removal of the melanoma, the surgeon should remove 2 cm of normal-appearing skin from all sides of the visible tumor. This wide local excision is necessary because melanoma cells can spread microscopically beyond the visible borders of the tumor. The 2 cm margin recommendation is based on clinical trials showing that this width provides the best balance between preventing local recurrence and minimizing surgical morbidity for intermediate-thickness melanomas (between 1-4 mm Breslow depth) 1.

Key Considerations

• The excision should extend down to the fascia (the layer covering the muscles) to ensure complete removal of any potential deep invasion.
• Following excision, the pathologist will examine the specimen to confirm that all margins are clear of melanoma cells.
• This surgical approach is considered standard of care for melanomas of this thickness and is crucial for reducing the risk of local recurrence while preserving as much normal tissue as possible.
• The recommendation is supported by the most recent and highest quality study, which prioritizes minimizing morbidity and mortality while maintaining quality of life 1.

Evidence Summary

• A study published in the Annals of Oncology in 2019 recommends a 2 cm excision margin for melanomas with a Breslow depth greater than 2 mm 1.
• Other studies, such as those published in the Journal of the National Comprehensive Cancer Network, also support the use of a 2 cm margin for intermediate-thickness melanomas 1.
• The evidence suggests that a 2 cm margin provides the best balance between preventing local recurrence and minimizing surgical morbidity.

From the Research

Excision Margins for 2.9mm Breslow Depth Melanoma

• The recommended excision margin for melanomas of the trunk, extremities, and head and neck that exceed 2 mm in depth is 2 cm 2.
• This guideline is based on a systematic review of the literature, including four systematic reviews and eight primary studies, and is intended to update the 2010 Cancer Care Ontario guideline on wide local excision margins and sentinel lymph node biopsy for melanoma.
• The study found that wide local excision margins of 2 cm are sufficient for melanomas with a Breslow depth of up to 2 mm, but for thicker melanomas, a wider margin may be necessary 2.
• Another study found that sentinel lymph node biopsy (SLNB) should be offered to patients with melanomas of the trunk, extremities, and head and neck that exceed 0.8 mm in depth 2.
• However, the therapeutic benefit of SLNB is not clear, pending randomized trial results, and the outcome for the overall cohort after wide local excision alone did not differ significantly from the outcome after additional SLNB 3.
• A study on the management of early-stage melanoma and Merkel cell carcinoma found that surgical management is the standard of care, with wide local excision ± sentinel lymph node biopsy, and that the importance of adequate margin of excision is crucial 4.
• The American Joint Committee on Cancer (AJCC) staging system is used to determine the thickness of the melanoma, and the Breslow depth is measured in millimeters 3.
• A multicentre study found that pain was the only significant factor influencing the quality of life after wide local excision and sentinel lymph node biopsy for melanoma, with 34% of patients reporting pain at their surgical site 5.