Abstract: Objective To study the characteristics of skin cancer and precancerous lesions and elucidate possible clues for the pathogenesis and provide feasible preventive measures. Methods The statistical analysis was performed based on the clinical dataset during 2013 to 2016, taken from the Dermatology Department of Peking University Third Hospital. Results The database summarized in-total 343 Non-melanoma skin cancer(NMSC) cases, in which the number of basal cell carcinoma(BCC) was 206, squamous cell carcinoma (SCC) 73 and actinic keratosis(AK) 81. The constituent ratio of BCC, invasive SCC and SCC in situ increased during the time. In general, no significant differences were found between the genders, where the elderly (over 60 years) dominate all types of NMSC. In details, BCC has a predilection to be found on the head and neck (79.6%), especially on the nose, similarly invasive SCC mainly occurred on the head and neck (61.1%). SCC in situ, on the other hand, mainly appeared on the trunk (34.6%). In addition, there were in-total 162 precancerous patients, in which the AK takes relatively big ratio. Conclusion The statistical analysis of NMSC from the database of our hospital was performed, indicating the constituent ratio of NMSC increased, in which BCC increased rapidly during the 4 years(2013-2016), involving mostly the elderly. The result suggests the environmental risk factors (UV, exhaust, PM2.5, etc.) which may induce the malignant skin tumors and further reveals the necessity to have early prevention education and early screening of skin cancer.

Key words: skin cancer, precancerous lesions, retrospective studies