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dermatology oncology surgery

Melanoma Breslow Thickness and Staging

Gives the AJCC 8th edition pathological T category of a cutaneous melanoma from Breslow thickness and ulceration (mitotic rate is no longer a T criterion). Guides excision margin and sentinel lymph node biopsy (SLNB) decisions (NICE NG14).

Score interpretation

pTis — Melanoma in Situ (Stage 0) 0

Melanoma confined to the epidermis.

→ Excise with a clinical margin of at least 0.5 cm (NICE NG14); discuss with the skin cancer MDT if the histological margin is inadequate. No SLNB or staging imaging.

pT1a — < 0.8 mm, Not Ulcerated 1

Stage IA if node-negative.

→ Wide local excision with a 1 cm clinical margin (stage I; NICE NG14). Do not offer SLNB or imaging for stage IA (NICE NG14).

pT1b — < 0.8 mm Ulcerated, or 0.8–1.0 mm 2

Pathological stage IA if node-negative (clinical IB).

→ Wide local excision with a 1 cm clinical margin (stage I; NICE NG14). Consider SLNB if 0.8–1.0 mm with ulceration, lymphovascular invasion or a mitotic index of 2 or more (NICE NG14).

pT2a — > 1.0–2.0 mm, Not Ulcerated 3

Stage IB if node-negative.

→ Wide local excision with a 1 cm clinical margin (stage I; NICE NG14). Consider SLNB (Breslow > 1.0 mm; NICE NG14).

pT2b — > 1.0–2.0 mm, Ulcerated 4

Stage IIA if node-negative.

→ Wide local excision with a 2 cm clinical margin (stage II; NICE NG14). Consider SLNB (Breslow > 1.0 mm).

pT3a — > 2.0–4.0 mm, Not Ulcerated 5

Stage IIA if node-negative.

→ Wide local excision with a 2 cm clinical margin (stage II; NICE NG14). Consider SLNB (Breslow > 1.0 mm).

pT3b — > 2.0–4.0 mm, Ulcerated 6

Stage IIB if node-negative.

→ Wide local excision with a 2 cm clinical margin (stage II; NICE NG14). Consider SLNB (Breslow > 1.0 mm). Consider staging CT (stage IIB). Oncology MDT: adjuvant immunotherapy may be considered for stage IIB–IIC.

pT4a — > 4.0 mm, Not Ulcerated 7

Stage IIB if node-negative.

→ Wide local excision with a 2 cm clinical margin (stage II; NICE NG14). Consider SLNB (Breslow > 1.0 mm). Consider staging CT (stage IIB). Oncology MDT: adjuvant immunotherapy may be considered for stage IIB–IIC.

pT4b — > 4.0 mm, Ulcerated 8

Stage IIC if node-negative.

→ Wide local excision with a 2 cm clinical margin (stage II; NICE NG14). Consider SLNB (Breslow > 1.0 mm). Offer staging CT (stage IIC). Oncology MDT: adjuvant immunotherapy may be considered for stage IIB–IIC.

Interpretation bands for the Melanoma Breslow. Apply clinical judgement and local guidance.

References

Related

Curated clinical cross-links plus same-class fallbacks.

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Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.