Index

British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma 2020

Guidelines

Gold standard: skin biopsy for histology

Preferred: full thickness incisional biopsy (containing both peripheral and deep margins)
Large / anatomically challenging area → incisional (punch) biopsy

1st line: standard surgical excision (in resectable primary disease)

Consider Mohs micrographic surgery after MDT if:

Tumour margin are not clearly visible / well-defined
At sites where tissue conservation is important (e.g. eyelid, lips, ears, fingers, genitalia)
At cosmetically sensitive areas (e.g face)

If surgery not appropriate: primary radiotherapy is an option

Peripheral surgical margins (determined under magnification / dermoscopy):

Also ensure at least 1mm histological clearance at all margins.

Low Risk	High Risk	Very High Risk
ALL the following must be met	ANY of the following	ANY of the following
Diameter ≤20mm (pT1) Thickness ≤4mm Invasion to dermis only No perineural invasion No lymphovascular invasion Histology: well or moderately differentiated	Diameter: 20-40mm (pT2) Thickness 4-6mm Invasion to subcutaneous fat Perineural invasion (dermal only) Histology: poorly differentiated Lymphovascular invasion Tumour at ear or lip Tumour arising within scar or area of chronic inflammation (i.e. Marjolin's ulcer)	Diameter >40mm (pT3) Thickness >6mm Invasion beyond subcutaneous fat Any bone invasion Perineural invasion (nerve ≥0.1mm or nerve beyond dermis or in named nerve) Histology: high grade subtype (adenosquamous, desmoplastic, spindle / sarcomatoid / metaplastic) In-transit metastasis

Low Risk

High Risk

Very High Risk

ALL the following must be met

ANY of the following

Invasion to subcutaneous fat
Perineural invasion (dermal only)
Histology: poorly differentiated
Lymphovascular invasion
Tumour at ear or lip
Tumour arising within scar or area of chronic inflammation (i.e. Marjolin's ulcer)

Invasion beyond subcutaneous fat
Any bone invasion
Perineural invasion (nerve ≥0.1mm or nerve beyond dermis or in named nerve)
Histology: high grade subtype (adenosquamous, desmoplastic, spindle / sarcomatoid / metaplastic)
In-transit metastasis

Author: Adams Lau
Reviewer:
Last edited: 15/07/25