Is Eradication of Actinic Keratosis (AK) Needed ?

Questions arising: when looking at a lesion and considering treatment
-Is the lesion an Actinic Keratosis (AK) which will turn into a Squamous Cell Carcinoma (SCC).
–Is it already an early SCC ?
-Will the treatment leave scars ?
-Is the damage already done ?
-Is AK an individual disease or is the problem part of a bigger disease called photodamage ?
-Is the treatment worse than the disease ?

When examining a patient clinically, or with a dermatoscope or with confocal microscopy, it is not possible to determine which one will progress into a SCC:
–untreated 0.025 to 16% of AK progress to SCC
–15% up to 63% of lesions regress after one year (in our experience around 25%)

In practice:
-it is impossible to remove every lesion (only the visible ones)
-many or most lesions are subclinical: not all can be seen so in practice no dermatologist can assume to have treated every lesion
–actually virtually all keratinocytes are damaged (called “field damage”)

…so follow-up should be regular:
-there is no age or gender difference after around 60 in the risk of developing AK
-if an SCC develops, there is an 82.4% to 100% of patients with a previous history of AK

Be careful in patients with photodamage !

Be careful in transplant recipients (immunosuppression) ! :
-the risk of developing AK is 65 times higher than in non-immunosuppressed individuals
-the risk of developing a premalignant tumor (AK, Bowen’s disease) is 40% in the first 5 years

Comments:
–there is a 5% risk SCCs metastizing
–Grading systems in SCC are not yet standardized but be could learn a lesson from the gynecologists who use brading systems for lesions which are morphologically similar: Cervical Intraepithelial Neoplasia (CIN I to III) and Vulvar Intraepithelial Neiplasia (VIN I to III). CIN III and VIN are considered as neoplasms in situ. Some AKs also contain Human Papilloma Viruses (HPV 21, 23 and 38)

 
Routine eradication is necessary. Bhatia N (USA). Routine eradication is unnecessary Cockerell (USA). CN09: Actinic Keratoses – Is routine eradication Necessary ?World Congress of Dermatology 2015 –  Vancouver, Canada