title: Risk of skin cancer development in 672 patients affected by actinic keratosis.
abstract: BACKGROUND
  Actinic keratoses (AKs) are the most common type of keratinocytic lesions worldwide. The skin areas affected by the so-called "field cancerization" harbor mutagenetic risks for the development of squamous cell carcinoma (SCC).
  
  
  METHODS
  We retrospectively investigated the histopathological reports and clinical charts of 672 patients affected by multiple AKs, presenting at least 5 years of follow-up. The frequency of non-melanoma skin cancers (NMSC, namely SCC and basal cell carcinoma [BCC]) and malignant melanomas (MMs) in patients affected by multiple AKs were analyzed.
  
  
  RESULTS
  More than 40% of patients with a previous diagnosis of multiple AKs developed an NMSC (SCC or BCC), or an MM, during a follow-up period of 5 to 11 years. The risk of developing another skin malignancy appeared to be higher in the age range between 61 and 80 years. The relative risk of developing a BCC and/or an MM in patients with a previous AK diagnosis was found to be 4.52.
  
  
  CONCLUSIONS
  The presence of multiple AKs and "field cancerization" seems to be associated with a high risk not only of NMSC such as SCC and BCC, but also of MM. An adequate follow-up is required in these groups of patients.
authors.affiliation: Section of Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy - alessiabarisani@gmail.com.
authors.forename: Emi
authors.initials: E
authors.lastname: Dika
authors.forename: Pier A
authors.initials: PA
authors.lastname: Fanti
authors.forename: Cosimo
authors.initials: C
authors.lastname: Misciali
authors.forename: Sabina
authors.initials: S
authors.lastname: Vaccari
authors.forename: Giuliana
authors.initials: G
authors.lastname: Crisman
authors.forename: Alessia
authors.initials: A
authors.lastname: Barisani
authors.forename: Carlotta
authors.initials: C
authors.lastname: Baraldi
authors.forename: Simone
authors.initials: S
authors.lastname: Ribero
authors.forename: Annalisa
authors.initials: A
authors.lastname: Patrizi
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002280:Basal Cell Carcinoma / Q000453:epidemiology / Q000209:etiology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055623:Keratosis, Actinic / Q000150:complications* / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology