Actinic keratosis (AK) is a common intraepithelial dysplastic lesion preceding Squamous Cell Carcinoma of the skin (SCC). It is the result of chronic sun accumulation.
Who is affected ?
(Risk factors)
-men are affected more than females
-old age
-fair skin and latitude (indeed as mentioned a study shows that prevalence in white Australians is the same as Europeans in the 70s)
–baldness: it develops mostly in elderly patients and on chronically sun exposed skin areas.
Incidence is increasing
-Australia has the highest frequency and because of increasing incidence costs in the United States are estimated to reach USD25 million in 2020 (around 20 million in 2012) (Study here: http://f1000research.com/articles/3-184/v2)
–prevalence varies widely and ranges from 1.4% to 58%:
- prevalence in white Australians is the same as Europeans in the 70s
- 10% of older men according to a study in Germans in 90000 employees)
- 37% had at least 1 AK according to a study from the Netherlands in 2000 males clinically examined by dermatologists. 10% had more than 10 Aks.
Switzerland has one of the highest global incidence of Skin Cancers (Melanomas and Keratinocyte Carcinomas). An aging population could be seen as the principal culprit but this rise can also be somewhat attributed to leisure activities high up Alps (such as skiing), where sun rays are stronger. moreover they tend to be shone perpendicularly on slopes as well as are reflected by snow in the winter. It is not surprising therefore that data on AK prevalence among the Swiss population is an important public health issue.
In this study outpatients in general patients were screened
-This prospective study enrolled 2844 consecutive patients of whom around 55% were females.
-A total of 49 General Practitioner offices were involved
Results
–a quarter of all patients (n=718) were diagnosed with AK. Men were affected more than females (58% of the diagnosed patients were males)
-The increase of AK prevalence was age-dependent
-Most of the AK developed on the head, arms and forearms.
-Half of the AK patients declared recreational UV exposure, while only 23 % declared occupational UV-exposure (15.74% of the patients were exposed UV exposed both occupationally and during leisure.
-AK distribution among sun-exposed body sites and extent of disease varied by sex.
-In Switzerland, AK is a common diagnosis in the general practitioner’s setting. Since it has been estimated that about 5% of AK may progress to invasive SCC, the prevention of AK, as well as patients’ and general practitioners’ education may play a critical role for subsequent SCC development.
Conclusion
This pilot study shows that AK could affect up to a quarter of individuals in Switzerland
This high number can be related to age as there is an age-related accumulation of sun exposure, an thus sun damage related to depletion of “sun capital”.
Take home message
These results shows the importance of educating Swiss Physicians about the screening of AK, along with the management strategies in coordination with dermatologists. A review of treatments in AK is available HERE (open access)
Comment
There is a variation which does not only depend on geographical factors (urban vs rural areas), but mostly to age, genetics (Fitzpatrick type) and behavioral factors of a given population
References: Poster 2401 – Piotr Dziunycz, Hofbauer G et al – Prevalence of actinic keratosis in general practice in Switzerland. AAD Annual Meeting 2016, Washington DC, USA (United States of America)
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