Tretinoin: lasting results, lingering doubts.

Tretinoin: Lasting results, lingering doubts

The latest study of tretinoin (Retin-A) shows the drug continues to reduce wrinkles, age spots and roughness for at least 22 months in patients with sun-damaged skin. Yet despite the good reviews, scientists still voice skepticism. Tretinoin "is somewhat controversial," says Edgar B. Smith, president-elect of the American Academy of Dermatology. He and others worry that doctors and patients are rushing to embrace the drug without waiting for the long-term research needed to prove its safety and efficacy.

In a follow-up study of 21 patients, John J. Voorhees and his colleagues at the University of Michigan Medical Center in Ann Arbor found sustained skin improvement when patients used the drug for 22 months. "I think the future of this particular agent is substantial," Voorhees said this week at the Academy's 47th annual meeting in Washington, D.C.

The 21 patients were among the original 30 participants in a study conducted by Voorhees, Jonathan S. Weiss and their colleagues, described earlier this year in the Jan. 22/29 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION. Patients treated with tretinoin in that study showed dramatic improvements that researchers documented with before-and-after photographs. But many doctors wondered whether these early effects would last (SN: 9/24/88, p.200). The new study suggests the drug continues to improve skin as long as it is used.

Smith, however, says the follow-up study is flawed because the 21 patients knew they were getting tretinoin treatment. He notes that the original study used a double-blind method of assigning patients to a control or treatment group. "If a study is not blinded," he asks, "can you really be objective about your results?"

In addition, some dermatologists have faulted the Michigan team for using photographs to measure tretinoin's efficacy. Many scientists regard pictures as a crude way to show skin improvement.

A new, coputerized method of measuring wrinkles may help dispel such criticism. "The system takes some of the subjectivity out of evaluation and gives us, for the first time, and objective method of measuring the drug's effect," says James J. Leyden of the University of Pennsylvania School of Medicine in Philadelphia, who helped develop the technique. Researchers make a rubbery cast of the skin, and a computer compares wrinkle dimensions before and after treatment. Leyden has used the system to analyze skin imprints from 40 people in a double-blind study. Those who received tretinoin for six months showed significant improvement compared with controls who were given a cream without the drug, he says.