Hormone Replacement Therapy as a Risk Factor for Non-Small Cell Lung Cancer: Results of a Case-Control Study

Abstract

Purpose: It was the aim of this study to assess the risk of lung cancer in postmenopausal women who received hormone replacement therapy (HRT). Experimental Design: This case-control study involves women who received medical services at Roswell Park Cancer Institute (RPCI) in Buffalo, New York, between 1982 and 1998, and who agreed to complete an epidemiological questionnaire. Participants with missing smoking data were excluded. The case group consisted of 595 women with primary lung cancer. Controls included 1,195 women, randomly selected from a pool of 5,845 eligible individuals, who received medical services at RPCI for non-neoplastic conditions; they had come to RPCI with a suspicion of neoplastic disease, but were diagnosed with neither benign nor malignant conditions. Controls were frequency matched 2:1 to cases on 5-year age intervals and exposure to smoking (ever/never). Cases and controls were comparable for age (means 61.3 and 61.0 years) and ever smoking (90%). Results: There were more former smokers among the cases (67 vs. 59% in controls); cases were less likely to be high school educated, were thinner, and were less likely to report HRT use compared with controls. Overall, hormone use was associated with a significant reduction in risk of lung cancer (adjusted odds ratio = 0.67; 95% confidence interval 0.53–0.85). Stratified analyses showed significant reductions in lung cancer risk in former smokers and women with normal to low body mass index. Conclusion: This study supports the hypotheses that there is a protective effect of HRT use on lung cancer risk in women.