Understanding Skin Cancer Risk and Prevention : with Emphasis on Actinic Keratosis Patients

Sammanfattning: The rising incidence of skin cancer globally makes it important to emphasize preventive measures that promote sun protection, particularly among individuals with phenotypic predisposition and/or risky sun habits. Actinic keratosis (AK) is the predominant actinic lesion observed in fair-skinned populations, recognized as a sign of actinic skin damage and as an occasional precursor to squamous cell carcinoma (SCC).   The aim of this thesis was to explore, from a primary care perspective, how an enhanced understanding of risk factors for skin cancer development can aid in identifying individuals for patient education on prevention and early detection of skin cancer.  Paper I suggests that personalized sun protection advice delivered in person by the GP can result in both short-term and long-lasting improvements in sun protective behaviour. Paper II demonstrated that individuals diagnosed with AK face a significantly elevated risk of developing SCC, basal cell carcinoma (BCC), or malignant melanoma (MM) in the following decade compared to sex- and age-matched controls. Paper III highlighted the fact that the presence of chronic lymphocytic leukaemia, and to a lesser degree hypertension and Parkinson's disease, independently raises the risk of skin cancer. This underscores the importance of providing tailored preventive guidance to individuals with these conditions. Paper IV showed that both age and male gender were factors found to be associated with an increased risk of developing skin cancer in AK patients while no risk increase was identified for any of the other variables studied.  In conclusion, personalized sun protection advice from general physicians (GPs) can bring about lasting improvements in sun protective behaviour. Reinforcing this advice during medical consultations, such as nevi checks, is important to sustain this effect over a long period. This is encouraging for the accepted practice of giving sun protection advice to patients with MM, SCC and BCC. A diagnosis of AK not only indicates an increased risk of skin cancer but also serves as a readily identifiable criterion for implementing personalized preventive measures. The presence of AK substantially increases the likelihood of developing future skin cancer, even more pronouncedly when combined with specific comorbidities such as chronic lymphocytic leukaemia, hypertension, and Parkinson's disease.   Future research should investigate how sun protection advice interacts with other behavioural counselling and evaluate its effectiveness over time. Additionally, exploring other factors influencing skin cancer risk in individuals with AK would facilitate the provision of comprehensive preventive interventions.