New research has shown that hormonal therapy for menopause already linked to an increase in breast cancer and strokes, also strongly increases the risk of death among women who develop lung cancer.
The findings are based on secondary analyzes of a study of 16,608 menopausal women in good health by the US government known as the Women's Health Initiative.
Researchers sought to evaluate the effects of Prempro, a combination of estrogen and progestin (a synthetic form of progesterone), sold by the US pharmaceutical Wyeth.
The analysis focused on the incidence of the most common form of lung cancer and its mortality rate over a period of nearly 5.5 years comparing women who followed the hormonal treatment and another group that took placebos.
There was no significant difference between the two groups in the rate of lung cancer, but the mortality rate after the diagnosis was two times higher among the women that were following hormonal therapy.
But menopausal woman who got lung cancer and followed hormonal treatment had a 61 percent higher chance of dying from the disease than the other women in the study.
Researchers headed by Rowan Chlebowski, an oncologist at the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, presented the findings here at the 45th annual meeting of the American Society of Clinical Oncology (ASCO), the biggest global cancer conference.
While breast cancer is the most common cancer in US women, lung cancer is the leading cause of cancer death among US women.
"We already know that combined hormone therapy has more risks than benefits," said the study's lead author Chlebowski.
The increase of risk of death among women who smoke and then follow hormone therapy "raises particular concerns," added Chlebowski.