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The Women's Heath Initiative (WHI) trial was a double-blind randomised placebo-controlled trial that examined the health benefits and risks of combined oestrogen and progestin in 16 608 postmenopausal women in the USA. The study was stopped early as health risks were shown to exceed benefits. In this study, both the incidence and mortality from lung cancer during the treatment and follow-up phases of the WHI (mean 7.9 years) were determined in a posthoc analysis.
No statistically significant differences in the incidence of lung cancer were seen between active (n=109) and placebo (n=85) groups (incidence 0.16% vs 0.13%; HR 1.23, 95% CI 0.92 to 1.63). More women died from lung cancer in the active (n=73) compared with the placebo (n=40) groups, and more deaths were seen in non-small cell lung cancer in the active (n=62; 0.09%) compared with the placebo (n=31; 0.05%) groups. There were no statistically significant differences in deaths from small cell lung cancer in the active (n=11; 0.02%) compared with the placebo (n=9; 0.01%) group.
Although there was no increase in the incidence of lung cancer in those on combined treatment, there was an increase in deaths attributable to lung cancer, especially in non-small cell disease. The authors speculate that combined hormone therapy stimulates growth of existing non-small cell lung cancers. This should be discussed with women considering combined hormone therapy, in particular those in a high-risk group.
▶ Chlebowski RT, Schwartz AG, Wakelee H, et al, for the Women's Health Initiative Investigators. Oestrogen plus progestin and lung cancer in postmenopausal women (Women's Health Initiative trial): a post-hoc analysis of a randomised controlled trial. Lancet 2009;374:1243–51.