(NaturalNews) Women who take the hormone replacement therapy (HRT) drug Prempro not only increase their risk of breast cancer, but their risk of death from lung cancer as well, according to a study conducted by researchers from the Medical Center at the University of California-Los Angeles and presented at a meeting of the American Society of Oncology.
"This is a new finding that tells us women who smoke shouldn't take estrogen and progestin for menopause symptoms," said study author Rowan Chlebowski.
Prempro, manufactured by Wyeth, was a best-selling treatment for the symptoms of menopause until 2002, when the Women's Health Initiative study revealed that HRT significantly increased women's risk of breast cancer and cardiovascular disease. Sales of the product plunged, although it still generated $1.1 billion for the company in 2008.
Menopause can lead to unpleasant symptoms such as hot flashes, fatigue, dizziness, headaches, muscle weakness, nausea and rapid heart beat.
The current study was based on an analysis of 16,608 participants in the original Women's Health Initiative study. The researchers found that current and former smokers who took Prempro were significantly more likely to die from lung cancer than women who received a placebo pill instead. This pattern held for non-smokers as well, although there were significantly fewer deaths than among smokers.
Nearly 80 percent of lung cancer cases in women are caused by tobacco use.
There were also more cases of lung cancer diagnosed in women taking HRT than those taking a placebo, but this difference did not achieve statistical significance.
The type of cancer in the study is known as non-small cell lung cancer, and accounts for 85 to 90 percent of all lung tumors. Both worldwide and in the United States, lung cancer kills more people than any other form of cancer. Roughly 200,000 new cases are diagnosed and approximately 160,000 people die from the disease in the United States each year.