MADRID — Regular use of a sunscreen prevented development of nonmelanoma skin cancer and reduced actinic keratosis counts in immunosuppressed organ transplant recipients in a 2-year, prospective, case-control study.
"I strongly believe, without being able to prove it, that sunscreen's protective mechanism involved blocking UV-induced impairment of cutaneous immunosurveillance. It's all about local immunity," Dr. Claas Ulrich said at the World Congress on Cancers of the Skin.
Dr. Claas Ulrich
The single-center study involved 60 organ transplant recipients in the active treatment arm—20 each with a donor heart, liver, or kidney—and an equal number of organ transplant recipient control patients.
Both groups received the same instructions regarding the importance of following a comprehensive photoprotection program including the avoidance of sun exposure between 11 a.m. and 2 p.m.; a strict prohibition on tanning beds; and routinely wearing long-sleeved shirts, trousers, and broad-brimmed hats.
The active treatment group also received a steady supply of a broad-spectrum sunscreen, free of charge, throughout the 2-year study. They were instructed to apply 2 mg/cm2 once daily to the head, neck, forearms, and hands, explained Dr. Ulrich, of the department of dermatology at Charité University Hospital, Berlin.
During the 2-year study, new invasive squamous cell carcinomas developed in 8 controls, but none of the sunscreen group. Nine controls developed new basal cell carcinomas, compared with two patients in the sunscreen group.
At baseline, patients in each group collectively had 191 actinic keratoses; after 24 months, the sunscreen group had 89 actinic keratoses, while the control group had 273.
Numerous studies have shown poor compliance with sunscreen use and other sun protection measures on the part of organ transplant recipients despite their markedly elevated rates of skin cancer.
In one study, for example, only 5% of 205 Canadian transplant recipients indicated they were committed to daily use of sunscreen. Thirty percent didn't use sunscreen at all. And 23% of the group continued to seek a tan (Am. J. Transplant. 2004;4:1852-8).
"When you ask patients why they don't use sunscreens, they say it takes too long to put on; they're messy, whitening, cosmetically unacceptable and very expensive if you buy high-quality sunscreens. We tried to optimize all those factors for the study," Dr. Ulrich said. "You need a good sunscreen. If we don't come close to their needs we've failed in our preventive strategies."
For the 2-year study, patients were supplied with Daylong Actinica, a broad-spectrum, once-daily, water-resistant lotion rated by the European Union as "very highly protective."
The study was sponsored by Spirig Pharma, which markets Daylong Actinica. Dr. Ulrich disclosed serving as a consultant to Spirig as well as Almirall, Novartis, and Wyeth (now part of Pfizer).