Background and Objective: To determine the incidence of new skin cancer formation in people who have had a nonmelanoma skin cancer (NMSC) removed. Methods: A prospective study of Australian outpatients with histologically confirmed nonmelanoma skin cancer (NMSC). Results: Four hundred eighty-one patients were entered in the study and 300 were followed for at least 10 years. Another skin cancer developed in 67.8% and multiple skin cancers (three or more) in 51.8%. A logistical regression analysis found that the main risk factors for new skin cancer formation were male sex and if the patient had multiple skin cancers. A squamous cell carcinoma (SCC) developed in 36% during the study and a melanoma in 4.7% of men and 2.1% of women. Men who had a NMSC were 8 times more likely than the general population to develop a melanoma while women with NMSC were 4 times more likely. Three patients died of metastatic SCC and one of metastatic melanoma during the followup period. A multivariate analysis showed that multiple skin cancer formation was the main risk factor for SCC or melanoma formation. Conclusion: Patients with NMSC require careful followup as they have an increased risk of new cancer formation. Those with multiple skin cancer merit particularly careful followup as all develop another NMSC within 10 years and have a significantly increased risk of developing SCC or melanoma.
A Prospective Study of Pain Control by a 2-Step Irradiance Schedule During Topical Photodynamic Therapy of Nonmelanoma Skin Cancer
