Estudio de los patrones de exposición solar en relación con el cáncer cutáneo

Abstract

ABSTRACT Skin cancer and aging, in addition to sharing similar etiopathological mechanisms, are two closely related processes with respect to their main external triggered factor, sun exposure. Last years, the model of studying this relationship has changed due to different involvement of sun exposure patterns in skin cancer development. The objetive of this study is to define the clinicopathological features, sun exposure patterns and photoaging of the three main skin cancers: squamous cell carcinoma, basal cell carcinoma and melanoma. It can be useful to compare this tumours, their solar exposure and skin aging, and to establish the relationship between them. We have studied 186 patients with skin cancer, 50 squamous cell carcinoma, 85 basal cell carcinoma and 51 melanomas. We used a validated questionnaire about sun exposure and we made a physical exam to collect all the information. With the first one were achieved the exposure variables (chronic, intermittent, acute and exposure during leisure activities outdoor) and about photoprotection (use of chemical or physical photoprotection measures); while with physical exam we studied the related variables with photoaging (actinic damage, periocular wrinkles and submentonian patterns, and glogau&apos;s classification of photoaging). Our results show that squamous cell carcinoma is related to high chronic sun exposure (> 50.000 hours), all signs of actinic damage, highest positions in photoaging classifications and the skin is more aged than expected for the age of patients. It appears in outdoor professions, located in head and neck, and it develops in older people than other tumors. Inttermitent sun exposure and burns are not related to this skin cancer. Melanoma is related to high intermittent sun exposure during childhood and adolescence (> 1.000 horas), in adults with exposures during maximum solar intensity time periods from 2.000 hours, low levels of chronic sun exposure (< 10.000 horas), as well as sun exposure pattern during leisure activities outdoor (> 10.000 horas) and burns, regardless of the age. We detect no relation with actinic damage and this tumor is located in lowest positions in photoaging classifications. Finally, basal cell carcinoma is related to a middle level of chronic sun exposure between melanoma and squamous cell carcinoma. With inttermitent sun exposure it appears from 2.000 hours, received between 10 am and 17 pm and above 20 years; and its location is related to burns anatomic regions. Basal cell carcinoma is located in chronic sun exposure areas (head and neck) and in the middle age between the other tumors. In conclusion, we have observed the differences in sun features between the three main skin cancers. While squamous cell carcinoma is a tumor related to photoaging and cumulative sun exposure during life, melanoma is hardly influenced for this factors, but it is related to intense sun exposure in a short term. Instead, basal cell carcinoma has dual behaviour, sharing features with two others.