June 3, 2009 (Orlando) -- The hormone replacement therapy taken by millions of women to relieve hot flashes and other symptoms of menopause may raise the risk of dying from lung cancer, researchers say.
New findings from the landmark Women’s Health Initiative study show that women with non-small cell lung cancer are 59% more likely to die from the disease if they take combined estrogen and progestin.
The risk was particularly high for smokers: There was one avoidable death from non-small cell lung cancer for every 100 women who both smoked and took hormone therapy over eight years, the study showed.
In light of the findings, “women almost certainly should not be using combined hormone therapy and tobacco at the same time,” says study head Rowan Chlebowski, MD, of the Harbor-UCLA Medical Center.
Hormone Therapy Linked to Host of Problems
The findings represent the latest in “a series of problems that work against widespread use of combined hormone therapy,” Chlebowski says.
He’s referring to the fact that previous analyses from the Women's Health Initiative showed that long-term use (at least five years) of hormone replacement therapy combining estrogen and progestin raises women's risk of heart disease, stroke, blood clots, and breast cancer.
In the WHI, more than 161,000 women were randomly assigned to take combined hormone therapy or a placebo. The trial was stopped prematurely in 2002, when it became apparent that the risks of combined hormone treatment outweighed the benefits.
Although fewer women are opting for the combination in light of those findings, about 25 million prescriptions are still written every year in the U.S., Chlebowski says.
Hormone Therapy and Lung Cancer
Since the WHI was stopped, researchers have observed a significant increase in both fatal and nonfatal cancers among women who took the hormones, Chlebowski tells WebMD.
The new analysis used data from the WHI to try to answer the question of whether the increase could be explained by the influence of combined hormone therapy on lung cancer, he says.
The researchers looked at lung cancer cases and deaths for the 5 1/2 years that the women took either hormones or placebo and for nearly 2 1/2 years afterward.
Among the findings, presented at the annual meeting of the American Society of Clinical Oncology:
- There were 67 deaths from non-small cell lung cancer among the 8,052 hormone users vs. 39 among the 7,678 women who took the placebo, a significant difference.
- After a diagnosis of non-small cell lung cancer, hormone users lived a median of 9.4 months, compared with 16.1 months for women taking placebo.
- Among smokers, 3.4% of those who took hormones died from non-small cell lung cancer, compared with 2.3% of those who took placebo.
- Among never-smokers, 0.2% of hormone users died from non-small cell lung cancer, compared with 0.1% of those on placebo.
- There was no link between hormone therapy and risk of developing or dying from small-cell lung cancer.
Bruce Johnson, MD, of the Dana-Farber Cancer Institute in Boston, tells WebMD that the new study was better designed and thus “likely more accurate” than previous studies that showed no link between lung cancer and hormone therapy.
Hormone Therapy: What Should Women Do?
Smokers should definitely quit the habit if they are taking or considering taking combined hormone treatment, Chlebowski says.
Also, talk to your doctor about other options for relieving hot flashes and symptoms of menopause, he says.
If hormone treatment is needed, heed the FDA’s advice to take estrogen and progestin at the lowest doses for the shortest duration to reach treatment goals, doctors say.