So a patient has skin cancer (duh duh duuuuh). How much of a margin should you give in your excision?

Like all things, this depends on the type of skin cancer

1. Basal Cell Carcinoma (BCC)
2. Squamous Cell Carcinoma (SCC)
3. Melanoma

Low-risk BCCs: 4 mm (high-risk: Mohs surgery)

Low-risk SCCs: 4 mm (high-risk: Mohs surgery)

Melanomas: depends on the tumour (T) stage, which is dependent on tumour thickness

• T1 (<1 mm): 1 cm margin (92% 10 year survival)
• T2 (1-2 mm): 2 cm margin (80% 10 year survival)
• T3 (2-4 mm): 2 cm margin (63% 10 year survival)
• T4 (>4 mm): 2 cm margin (50% 10 year survival)
• Though it might seem counterintuitive that once you’re past 1 mm thickness, you don’t have a bigger margin, but larger margins haven’t been shown to increase survival