A Trial to Compare the Incidence of Squamous Cell Carcinoma (SCC) and Other Skin Neoplasia on Skin Areas Treated With Ingenol Disoxate Gel or Vehicle Gel for Actinic Keratosis on Face and Chest or Scalp

Inclusion Criteria: * Signed and dated informed consent has been obtained. * The subject has been treated in one of the trials LP0084-1193, -1194, -1195, or -1196 and has been evaluated at the end of follow-up visit (month 14) of that trial. Exclusion Criteria: * The subject is in need of treatment with ingenol mebutate or ingenol disoxate in the selected treatment area . * The subject is enrolled in any other interventional clinical trial. For subjects where there is a gap between end of follow-up visit (month 14) in one of the trials LP0084-1193, -1194, -1195, or -1196 and participation in the current trial: * The subject has been treated with ingenol mebutate or ingenol disoxate in the selected treatment area after end of follow-up visit (month 14) in one of the trials LP0084-1193, -1194, -1195, or -1196 and until participation in the current trial. * The subject has been enrolled in any other interventional clinical trial after end of follow-up visit (month 14) in one of the trials LP0084-1193, -1194, -1195, or -1196 and until participation in the current trial.