Findings from the post-intervention period (mean, 2.4 years) of the Women’s Health Initiative trial suggested that combined hormone therapy might increase lung cancer mortality. In the present post-hoc analysis of the trial, Dr. Rowan T. Chlebowski and colleagues assessed lung cancers that were diagnosed during both the intervention and post-intervention periods—a total follow-up period of 7.9 years, on average.
The original trial included 16,608 postmenopausal women: 8506 who received conjugated equine estrogen 0.625 mg and medroxyprogesterone 2.5 mg once daily, and 8102 who received placebo.
During follow-up, 109 women in the hormone therapy group and 85 in the placebo group were diagnosed with lung cancer, Dr. Chlebowski, from Harbor-UCLA Medical Center, Torrance, California, and colleagues note. The corresponding annual rates were 0.16% and 0.13% (p = 0.16).
Non-small cell lung cancer accounted for 96 cases in the hormone therapy group and 72 in the placebo group. The corresponding annual rates were 0.14% and 0.11% (p = 0.12).
As noted, lung cancer-specific death rates were higher in the hormone therapy group. Overall, 73 deaths from the malignancy were seen in the hormone therapy group compared with 40 in the placebo group, which translates into annual rates of 0.11% and 0.06%, respectively (p = 0.01).
The lung cancer mortality difference, the authors note, was mainly due to a higher number of deaths from non-small-cell lung cancer in the hormone therapy group: 62 vs. 31 deaths. No significant difference in the incidence or mortality from small cell lung cancer was noted between the groups.
“Today’s results and previous analyses on lung-cancer-related outcomes provide sufficient evidence to recommend discontinuation of hormone-replacement therapy once lung cancer is diagnosed,” Dr. Apar Kishor Ganti, from the University of Nebraska Medical Center, Omaha, comments in a related editorial.
“Because the optimum safe duration of hormone-replacement therapy in terms of lung-cancer survival is unclear, such therapy should probably be avoided in women at high risk of developing lung cancer, especially those with a history of smoking,” Dr. Ganti adds.