This protocol covers squamous cell carcinoma in situ (Bowen's disease) presenting as a skin lesion larger than 2 cm situated at a low-risk site — trunk or limbs — in a patient who is not immunosuppressed. Lesions exceeding 2 cm are classified as large and have distinct management considerations compared with smaller lesions or those at high-risk anatomical sites.
First-line options for this specific scenario include a light-based therapeutic approach or a topical treatment modality, with the choice guided by lesion characteristics and patient factors. The complete evidence-based regimen, selection criteria, and clinical algorithm are available in the full protocol.
DOI: 10.1093/bjd/ljac042
Lesions are considered large if > 2 cm and are considered high risk at periocular and digital (and penile) sites.
Offer* conventional, red-light PDT as a treatment option to people with SCC in situ, particularly for poorly healing or cosmetically sensitive skin sites, multiple lesions and large lesions.
Consider topical 5-fluorouracil (5%) monotherapy in people with SCC in situ, for larger lesions in low-risk sites, and in those who will not or cannot undergo treatment with other better-established therapies. Initiate a standard regimen of once- or twice-daily application for up to 4 weeks.
Clearance (within 6 months) (9)
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