Nonmelanoma skin cancer primary prevention

Metastasis is a process by which malignant cells leave their primary site and spread to distant locations throughout the body. It is the formation of metastasis that makes cancer such a lethal disease. The presence of metastasis is therefore the main cause of morbidity and mortality in patients with cancer. While primary tumors are potentially resectable, most metastases are resistant to all current forms of cancer treatment. Approximately 30% of patients with newly diagnosed solid cancers (excluding nonmelanoma skin cancers) have clinically detectable metastases, while another 30% may have occult micrometastases (L2). Clearly, to reduce mortality from cancer, we have to be able to prevent or treat metastasis. 

Frieling, U.M. et al., A randomized, 12-year primary-prevention trial of beta carotene supplementation for nonmelanoma skin cancer in the physician s health study, Arch. Dermatol., 136, 179, 2000. 

Secondary prevention defined as subjects with documented cancer including nonmelanoma skin cancer (although some of the primary prevention trials did not exclude those with nonmelanoma skin cancer at baseline). 

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