Combination hormone replacement therapy (HRT) has long been associated with risks of stroke, blood clots, and breast cancer. Now researchers have linked combination HRT to an increased risk of dying of non-small cell lung cancer.
Rowan Chlebowski, M.D., Ph.D., of Harbor-UCLA Medical Center in Los Angeles, and his colleagues report the findings from the Women's Health Initiative which show using estrogen and progestin led to a 59% increase in the risk of death if a woman developed non-small cell lung cancer.
The Women's Health Initiative study of combined hormone therapy enrolled 16,608 postmenopausal women ages 50 through 79 and randomized them to get placebo or the two hormones. The study was stopped early when some of the findings began to show harms outweighing the benefits. These harms included the researchers noticing a significant increase in both fatal and non-fatal malignancies among those who took the hormones. This lead to specifically looking at the effect of the hormones on lung cancer in an effort to understand the increase.
There were 67 deaths among the 8,052 women on hormones and 37 among the 7,678 women in the placebo group. For small cell lung cancer, there was no difference in incidence or mortality, but for non-small cell lung cancer, analysis showed:
* A significant increase in the risk of dying if a woman taking the hormones developed cancer.
* Women who got lung cancer in the placebo group lived almost twice as long as the ones who took HRT. Median survival of 9.4 months in the hormone arm, compared with 16.1 among women in the placebo arm.
* A trend to more cases of the disease in the hormone arm.
Many postmenopausal women still use the combined hormone therapy. Between 25 and 30 million prescriptions are written every year with 15% of postmenopausal women still using the combination. If a woman does choose to take combined HRT, then it would be in her best interest to not smoke.
Non-small cell lung cancer and estrogen plus progestin use in postmenopausal women in the Women's Health Initiative randomized clinical trial; J Clin Oncol 2009; 27(15S): Abstract CRA1500. ; Chlebowski RT, et al