Photodynamic therapy does not prevent cutaneous squamous-cell carcinoma in organ-transplant recipients: results of a randomized-controlled trial.

A randomized-controlled trial with paired observations was performed with 40 organ-transplant recipients to assess the preventive effect of photodynamic therapy (PDT) on the development of new squamous-cell carcinomas and to evaluate the effect of PDT on the number of keratotic skin lesions. The treatment area consisted of a randomly assigned forearm and the corresponding hand, whereas the other forearm and hand served as the control area. After the initial visit, follow-up visits were scheduled at 3-monthly intervals during 2 years. No statistically significant difference was found in the occurrence of new squamous-cell carcinomas between the treated and untreated arms: after 2 years of follow-up, we observed 15 squamous-cell carcinomas in nine out of 40 PDT-treated arms and 10 squamous-cell carcinomas in nine out of 40 control arms. The number of keratotic skin lesions increased in both arms, but was less pronounced in the PDT-treated arm. After 1 year of follow-up, a trend in favor of the PDT-treated arm was observed, but statistical significance was not reached. Nearly 80% of the patients reported mild to severe adverse effects consisting of pain and a burning sensation, immediately after the treatment. No long-term adverse events were noted. In conclusion, PDT does not appear to prevent the occurrence of new squamous-cell carcinomas in organ-transplant recipients, but to some degree, reduces the increase of keratotic skin lesions.

The influence of painful sunburns and lifetime sun exposure on the risk of actinic keratoses, seborrheic warts, melanocytic nevi, atypical nevi, and skin cancer.

Painful sunburns are implicated in the pathogenesis of squamous cell carcinoma, basal cell carcinoma, and malignant melanoma. Chronic exposure to ultraviolet radiation is known as the most important risk factor for the development of actinic keratoses and squamous cell carcinoma. The purpose of the study was to assess the effect of painful sunburns and lifetime sun exposure on the development of actinic keratoses and seborrheic warts in relation to the development of squamous cell carcinoma and basal cell carcinoma, and on the development of melanocytic nevi and atypical nevi in relation to the development of malignant melanoma. We made use of a cohort of 966 individuals who participated in a case-control study to investigate environmental and genetic risk factors for skin cancer. Exposure measurements for sunlight were collected and actinic keratoses, seborrheic warts, melanocytic nevi, and atypical nevi were counted. Relative risks were estimated using exposure odds ratios from cross-tabulation. Multivariate logistic regression was used to adjust for potential confounders. The recall of painful sunburns before the age of 20 y was associated with an increased risk of squamous cell carcinoma, nodular basal cell carcinoma, and multifocal superficial basal cell carcinoma as well as actinic keratoses. Odds ratios with 95% confidence intervals adjusted for age, sex, and skin type were 1.5 (0.97; 2.3); 1.6 (1.1; 2.2); 2.6 (1.7; 3.8); and 1.9 (1.4; 2.6) for the three types of nonmelanoma skin cancer and actinic keratoses, respectively. Painful sunburns before the age of 20 y were also associated with an increased risk of malignant melanoma and the development of its precursors, melanocytic nevi and atypical nevi. Odds ratios with 95% confidence intervals adjusted for age, sex, and skin type were 1.4 (0.86; 2.1); 1.5 (1.1; 2.0); and 1.4 (0.88; 2.3) for malignant melanoma and the two types of precursors, respectively. Lifetime sun exposure was predominantly associated with an increased risk of squamous cell carcinoma (p-value for trend=0.03) and actinic keratoses (p-value for trend <0.0001) and to a lesser degree with the two types of basal cell carcinoma. By contrast, lifetime sun exposure appeared to be associated with a lower risk of malignant melanoma, despite the fact that lifetime sun exposure did not diminish the number of melanocytic nevi or atypical nevi. Neither painful sunburns nor lifetime sun exposure were associated with an increased risk of seborrheic warts.

Effect of smoking and sun on the aging skin.

Smoking and ultraviolet radiation are known to have a detrimental effect on human skin. Important characteristics of the aging skin are elastosis and telangiectasia. The purpose of the study was to assess the relative importance of age per se, and the detrimental effects caused by sun exposure and smoking on the development of cutaneous elastosis and telangiectasia in a well-defined group of individuals. We made use of 966 individuals who participated in a case-control study to investigate environmental and genetic risk factors for skin cancer. Exposure measurements for sunlight and smoking were collected and the amount of elastosis and telangiectasia in the face and neck was recorded according to a four-graded score varying from none to severe. Relative risks were estimated using exposure odds ratios from cross-tabulation and logistic regression. Multivariate logistic regression was used to adjust for potential confounders. Among both sexes a strong association was observed between increasing age, sun exposure, and amount of elastosis. The association between increasing age, sun exposure, and amount of telangiectasia was strong among men, but less apparent among women. Smoking was also associated with elastosis among both sexes, and with telangiectasia predominantly among men. Intrinsic differences between men and women (e.g., hormones) or behavior differences (e.g., more frequent use of creams and cosmetics among women) could account for this apparent difference in the occurrence of telangiectasia. In contrast to elastosis, telangiectasia may not be a good marker of the aging skin, specifically not in women.