VANCOUVER - BC Cancer Agency (BCCA) researchers have determined that children who use a broad-spectrum, high-sun protection factor (SPF) sunscreen as a matter of routine, develop significantly fewer of the moles that can lead to melanoma. The three-year BCCA study involved hundreds of B.C. school children and is the first randomized study of its kind.

Melanocytic nevi - largely caused by sunlight - are the dark brown or black moles/blemishes that develop in childhood. Up to half of all melanomas arise from these pre-existing moles. And although it's widely accepted that lowering the number of new nevi a person develops can decrease the risk of melanoma, there has been debate on what role sunscreen can play in that process.

BCCA researchers, with the cooperation of the Vancouver School Board and its teachers, recruited 458 grades one and four elementary school children for this research. At the end of the three-year reporting period, data was collected and analyzed on the 309 children who completed the study.

At the beginning of the study each child's nevi, regardless of size, were counted. The children were then split into two groups.

The first group (222 children) received a supply of SPF 30 broad-spectrum (protects against both UV-A and UV-B radiation) sunscreen with instructions for parents to apply on their child if he/she was going to be in the sun for 30 or more minutes. After one month the sunscreen bottles were measured to determine how much sunscreen was used and a second bottle was issued for use during the July-August period. Parents followed this routine and recorded detailed information on sun exposure and sunscreen use over three summers, and during any family Christmas or spring break vacations that took place in sun destinations.

The other 236 children were given no sunscreen. The goal was to determine the number of new nevi acquired during the three years between the treatment and control groups.

Because of a strong general awareness of sun protection importance, substantial use of sunscreen was reported in the control group. However, the children whose parents received high-quality information and the broad-spectrum, high-SPF sunscreen, still developed fewer nevi than the other children did.

Moreover, the study results also indicate that sunscreen is of major importance for children with freckles or who freckle easily. In fact, the freckled-faced children in the treatment group developed 30-40% fewer new nevi than the freckled children who did not receive sunscreen.

Richard Gallagher, leader of Cancer Control Research at the BC Cancer Agency, and the study's principal investigator, says there was virtually no difference between the amount of sun each group was exposed to or the kind of clothing the kids wore. "This is what is so encouraging - the only significant behavioral difference was the amount and frequency of sunscreen use," he said.

"This is a true prevention study," Mr. Gallagher continued. "Parents need to know that if they intervene early they can probably significantly reduce their child's risk of skin cancer in the future."

The study, funded by the BC Health Research Foundation, is the first time nevus density has been measured in children and followed up years later. Gallagher says this is what sets this research apart from past studies that suggest there is no connection between sunscreen and nevus, or melanoma development.

"In those studies," he explained, "researchers used retrospective data. They spoke with patients already diagnosed with malignant melanoma and asked them to provide details about their childhood sun exposure, sunscreen habits, and mole history."

"There is just too much room for error when you rely on memory," Gallagher added.

Dr. Jason Rivers, a dermatologic oncologist (in practice at the BC Cancer Agency and the Vancouver Hospital) and co-principal researcher for the study, helped develop the nevus counting procedure. "There's been a lot of debate, but the results show that the kids who used sunscreen ended up with fewer moles. And fewer moles probably means less risk for melanoma when they grow up," Dr. Rivers said.

He is quick to point out however, that parents should not rely on sunscreen alone for protection. Children should always wear protective clothing (hats, tee shirts, sunglasses etc.,) and parents should carefully monitor how long they have been out in the sun.

"The rain and snow makes us pretty anxious to get out in the sunshine, but you have to be extremely careful," Dr. Rivers warned.

As the parent of two young children himself, Dr. Rivers outfits both his kids in "Australian-style" bathing suits that cover 60-70 per cent of their body surface. They also use a high-SPF sunscreen on the children's legs, arms and faces.

"Sure, we take it seriously in our house," Dr. Rivers continued. "But when you see people dying of skin cancer, you don't need much convincing it's the right thing to do. Adults should be doing the same thing for themselves."

Results of the study will be published June 14th, 2000 by the Journal of the American Medical Association in a paper entitled: Broad Spectrum Sunscreen Use and the Development of New Nevi in White Children.

For a copy of the paper, visit www.ama-assn.org