New, quicker treatment for solar keratoses

Solar keratoses are a common pre-cancer condition affecting approximately 50% of white Australians over 40 years old.¹

When they are present in small numbers, they are usually easily and quickly treated by cryotherapy (freezing). But if many solar keratoses are present, cryotherapy is impractical due to the number of lesions and also because it can only treat visible lesions – it doesn’t treat the preclinical solar keratoses which are present but not yet visible.

Various field treatments have been used to treat the general sun damaged area: for example, the upper face, backs of hands, forearms or chest. Until recently, the treatment with the most success has been fluorouracil cream.² Unfortunately, while highly effective, this cream has several problems:

• Must be used twice daily for four weeks or longer.
• Pain during treatment (sometimes so severe that treatment needs to be discontinued).
• Redness, sores, crusts and peeling of the skin.
• Exposure to sunlight is prohibited during treatment.

Good news is that there’s now a new way of using fluorouracil: in combination with calcipotriol, a form of vitamin D which stimulates immune system cells that have anti-cancer effects.

This combination causes less inflammation and other side effects, only needs to be used for 4 days (not 4 weeks) and reduces the risk of squamous cell carcinoma in the treated area for up to 3 years. ^{3, 4, 5}

In addition, the price is cheaper than the now-discontinued 3-day treatment, ingenol mebutate.

The combination of fluorouracil and calcipotriol is not yet commercially available in most pharmacies; it must be prepared in a specialist compounding pharmacy.

This medication has potential side effects, it is only available on prescription to patients attending a skin cancer doctor or dermatologist.

References

1. Chia A, Kim A, Shumack S et al, 2007. Actinic keratoses, in Australian Family Physician, 36(7). https://www.racgp.org.au/afp/backissues/2007/17422
2. Jansen M, Kessels J, Nelemans P et al, 2019. Randomized trial of four treatment approaches for actinic keratosis. N Engl J Med 2019; 380:935-946. http://dx.doi.org/10.1056/NEJMoa1811850
3. Cunningham TJ, Tabacchi M, Elaine JP et al, 2016. Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy. J Clin Invest. 2017;127(1):106-11. https://doi.org/10.1172/JCI89820
4. Bricknell J, 2021. Topical treatment for actinic keratosis. Australasian Skin Cancer Congress. Session 3, 28 May 2021. Gold Coast, Australia and online.
5. Rosenberg A R, Tabacchi M, Ngo K H et al, 2019. Skin cancer precursor immunotherapy for squamous cell carcinoma prevention. JCI Insight. 4(6):e125476. https://doi.org/10.1172/jci.insight.125476