Actinic keratosis, Bowen disease and other premalignant skin lesions
Actinic keratosis and field cancerisation, when to biopsy, lesion versus field treatment (fluorouracil wins head to head), Bowen disease (SCC in situ) and its sites that behave differently, actinic cheilitis, cutaneous horn and other precursors.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Actinic keratoses (AKs) are UV-induced keratinocyte dysplasia. Australia has the highest prevalence in the world: about half of fair-skinned Australians over 40 have them.
- AKs mark a field of UV damage (field cancerisation). Each lesion has a low risk of becoming SCC, but the patient's overall risk of keratinocyte cancer is high.
- Bowen disease is SCC in situ (full-thickness epidermal dysplasia). About 3 to 5% progress to invasive SCC.
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Sources
- Clinical practice guidelines for keratinocyte cancer: basal cell carcinoma, squamous cell carcinoma and related lesionsAU/NZCancer Council Australia (approved by NHMRC November 2019), 2019 (current; no newer version found on search, November 2026)
- Therapeutic Guidelines: DermatologyAU/NZTherapeutic Guidelines Limited, Version 5, 2022
- Kandolf L et al. European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization. J Eur Acad Dermatol Venereol 2024;38:1024-1047EADO, EDF, EADV and UEMS, 2024 (no later revision found, November 2026)
- Eisen DB et al. Guidelines of care for the management of actinic keratosis. J Am Acad Dermatol 2021;85:e209-e233American Academy of Dermatology, 2021
- Eisen DB et al. Focused update: guidelines of care for the management of actinic keratosis. J Am Acad Dermatol 2022;87:373-374.e5American Academy of Dermatology, 2022 (adds a strong recommendation for tirbanibulin)
- Sharma A et al. British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022. Br J Dermatol 2023;188:186-194British Association of Dermatologists, 2022
- Jansen MHE et al. Randomized trial of four treatment approaches for actinic keratosis. N Engl J Med 2019;380:935-946New England Journal of Medicine, 2019
- Criscione VD et al. Actinic keratoses: natural history and risk of malignant transformation in the Veterans Affairs Topical Tretinoin Chemoprevention Trial. Cancer 2009;115:2523-2530Cancer, 2009
- Imiquimod 5% cream PBS listing, item 2637T (General Schedule lists superficial BCC only)AU/NZPharmaceutical Benefits Scheme, Checked November 2026
- Imiquimod cream (Aldara) for superficial basal cell carcinoma (notes face and scalp solar keratosis is RPBS-subsidised, not PBS)AU/NZAustralian Prescriber, 2013
- AusPAR: Onakta (tirbanibulin)AU/NZTherapeutic Goods Administration, 2024 (ARTG 391198, entered 23 February 2024)
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy