Environmental factors’ contribution in skin cancer etiology
Skin cancers are the most frequent types of malignant tumors worldwide, being mostly found in light-skinned populations, with a ratio of 30%. Approximately 3 million non-melanoma skin cancers and 132000 melanoma cases are diagnosed globally each year. The most frequent skin cancers are the basal cell carcinoma, squamous cell carcinoma and malignant melanoma. The incidence, morbidity and mortality of skin cancers are on the rise and have become a major public health concern. We aim to review the most important environmental factors involved in the development of skin cancers, along with the incidence rates and preventive behaviors or strategies (including personal behavioral changes and public educational initiatives). Ultraviolet radiation (UVR) is a well-known physical hazard, responsible for photoaging, photoallergy and phototoxic reactions, being heavily involved in carcinogenesis, including melanoma development. Overexposure to natural and artificial UVR is a public health problem. Sunburns, especially in childhood, are an important risk factor for melanoma development. Excessive exposure causes cumulative damage which determines immune suppression and skin cancer initiation. Transplant patients and AIDS patients have an increased incidence of skin cancer. Some treatment methods, including radiotherapy, phototherapy and psoralen and ultraviolet A (PUVA) therapy can lead to skin cancer development. Viral infections such as those with human papilloma virus can trigger the initiation of squamous cell carcinoma. Patients with familial genetic syndromes are highly sensitive to certain types of skin cancers. Ionising radiation, environmental pollutants, chemical carcinogenic agents and work exposure have been associated with skin cancer. Artificial UV radiation exposure (tanning beds and lamps), aging, skin color, personal diet and smoking are important risk factors. Ultraviolet radiation is the main etiological agent in skin cancer development. A better understanding of the causative factors is an essential step in skin cancer prevention.