CHICAGO5 (Reuters) – A cream used to treat the early signs of skin cancer may erase wrinkles and leave behind younger-looking skin, US researchers said yesterday.

They said Valeant Pharmaceuticals' cream Efudex, which is used to treat actinic keratoses, a precancerous form of squamous cell carcinoma, improved the appearance of skin, smoothing out rough spots and wrinkles, improving skin colour, and erasing brown spots.

Sachs said the cream appears to be causing a wound healing response that leads to an increase in collagen production, which is improving the appearance of wrinkles.

"The drug has been around for many years," said Dr. Dana Sachs of the University of Michigan, whose study appears in the Archives of Dermatology.

Sachs said it has been used for four decades to treat actinic keratoses, which appear as a scaly or crusty bump on the skin. They most commonly appear on sun-exposed areas such as the face, neck, forearms or lips.

Treatment with Efudex, known generically as fluorouracil, is not trouble-free. Soon after the cream is applied, the skin becomes red and inflamed.

"Patients look really bad," Sachs said in a telephone interview. "Their skin is red. I've heard people describe it as looking like raw hamburger meat."

But after the treatment, patients have said their skin looks younger. "People have commented for years that they look better. Not only are their pre-cancers gone but the quality of their skin seems to be improved," Sachs said.

Sachs and colleagues wanted to see if they could actually measure a difference in the appearance of skin.

They studied 21 people aged 56 to 85 with actinic keratoses and sun damage. The volunteers used the cream twice daily on the face for two weeks and the team measured changes in the skin, taking facial biopsies over a six-month period.

The drug had a significant effect.

"People's skin was much softer," Sachs said. "The texture was improved. There are fewer wrinkles around the upper cheek and eyes."

The researchers also noticed skin appeared less yellow and more even toned with fewer brown spots.

Sachs said for patients with precancerous spots, the findings may be an added inducement to finish treatment. It may be useful at treating the signs of sun damage in other patients as well, she said.

Actinic keratoses are caused by years of sun damage and can lead to squamous cell carcinoma, one of the two most common types of skin cancer that represent more than one million new cases each year. They are easily treated and rarely kill unless completely neglected.