ORLANDO, Florida (Reuters) - Use of menopausal hormone-replacement therapy increases the risk of death from lung cancer by 60 percent after five years, U.S. researchers reported on Saturday.

For smokers, the trial found that use of Prempro, Wyeth’s combined estrogen/progestin hormone-replacement therapy, caused an extra death from non-small cell lung cancer for each 100 women during the study.

Doctors once thought that hormone therapy, or HRT, could protect women from chronic diseases, especially heart disease.

But use of the drugs plunged after 2002 when the large Women’s Health Initiative study found that HRT could raise the risk not only of breast and ovarian cancer, but of strokes and other serious conditions.

“Women almost certainly shouldn’t be using hormone replacement therapy and tobacco at the same time,” said Dr. Rowan Chlebowski, a medical oncologist Harbor-UCLA Medical Center in Los Angeles and lead author of the study, which analyzed data from the WHI trial.

Since 2001, sales of Wyeth’s hormone-replacement products have plunged by about 50 percent to around $1 billion a year, and the bulk of sales are now estrogen-replacement drug Premarin and cream formulations, said Joseph Camardo, head of medical affairs at Madison, New Jersey-based Wyeth.

“Practice has already changed significantly,” he said. “Guidance and the label have changed ... use has shifted toward much shorter duration and lower doses.”

The Wyeth official noted that the average age of women in the WHI study was 63, and the participants used high doses of Prempro over long periods of time.

Chlebowski said previous research suggested that hormones play a role in non-small cell lung cancer, the most common form of the disease, because women tend to have higher survival rates than men and respond better to certain therapies.

His study, presented here at a meeting of the American Society of Clinical Oncology, was the first to show a correlation in a randomized clinical trial setting.