INTRODUCTION
Squamous cell carcinoma (SCC) represents the second most common skin cancer in Europe.1,2 This may arise from precancerous lesions such as actinic keratosis (AK), actinic cheilitis, oral leukoplakia, and chronic radiodermatitis. Although the risk of progression from an AK to an invasive SCC is low, it is estimated that 60% to 97% of the SCCs originates from AKs.3,4
AK is a pre-malignant lesion that affects more than 60% of the elderly population in Europe.1 Once developed, AK can follow different evolutionary courses, from spontaneous involution, stable persistence, to progression into intraepithelial carcinoma (IEC) or invasive SCC. Although the actual risk of progression cannot be exactly measured, rates can vary from 5 to 20% in 10 to 25 years.5,6,7,8,9 IEC can progress to invasive SCC in 3 to 5% of cases10 with a potential risk for metastasis of up to 10%.11
Patients with multiple AKs in a particular region have this affected area called the cancerization field. Cancerization field is a region containing subclinical and multifocal pre-neoplastic abnormalities with genetic mutations that may constitute the site of multiple primary tumors.7,12,13
AK is a pre-malignant lesion that affects more than 60% of the elderly population in Europe.1 Once developed, AK can follow different evolutionary courses, from spontaneous involution, stable persistence, to progression into intraepithelial carcinoma (IEC) or invasive SCC. Although the actual risk of progression cannot be exactly measured, rates can vary from 5 to 20% in 10 to 25 years.5,6,7,8,9 IEC can progress to invasive SCC in 3 to 5% of cases10 with a potential risk for metastasis of up to 10%.11
Patients with multiple AKs in a particular region have this affected area called the cancerization field. Cancerization field is a region containing subclinical and multifocal pre-neoplastic abnormalities with genetic mutations that may constitute the site of multiple primary tumors.7,12,13