Patient deaths that led to a clinical trial being halted early may have had nothing to do with the anti-cancer cream being tested, U.S. researchers say.

The trial was testing a cream containing tretinoin, a retinoid commonly used to treat acne and other conditions, to prevent skin cancer.

A total of 1,131 veterans -- 97 percent male -- with an average age of 71 years were randomly assigned to apply either a cream containing 0.1 percent tretinoin or an unmedicated cream daily to their face and ears. They were examined by a dermatologist every six months.

When a report identified a statistically significant increase in the number of deaths among study participants using tretinoin, the trial was stopped six months early in May 2004.

A team led by Dr. Martin A. Weinstock of the VA Medical Center and Brown University in Providence, R.I., assessed the data and concluded analyses did not support tretinoin as a cause of death. They said participants' smoking status had not been verified, but many of the treatment group deaths were smoking associated and some studies suggest smoking may interact with certain compounds.

"We do not conclude that this trial provides appropriate grounds for hesitating to use topical tretinoin in clinical practice in the absence of additional evidence," the study authors said in a statement.

The findings are published in the Archives of Dermatology.