Purpose: Some epidemiological data suggest that sex hormones may influence lung cancer risk, and estrogen receptors have been found in human non-small cell lung tumors. We assessed the relation of the use of estrogen replacement therapy (ERT) to the risk of lung cancer in our hospital-based Case-Control Surveillance Study, conducted in four US centers during 1976 to 2001.
Methods: Cases were 662 women aged 40 through 74 years with lung cancer and controls were 4671 women admitted for conditions unrelated to ERT use. We used multivariate unconditional logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) for ERT use for at least 3 months compared to no use or use for less than 3 months.
Results: The OR for lung cancer among ERT users was 1.0 (95%CI 0.8-1.4), and it was 1.0 (95%CI 0.7-1.4) among users of conjugated estrogens only. Risk did not increase as the duration of use increased. Odds ratios for specific lung cancer cell types were not significantly increased or decreased for use of ERT or conjugated estrogens. There were non-significant increases for non-small cell types other than squamous, but there was no consistent pattern across duration of use.
Conclusion: Our data do not support an increased risk of lung cancer among women who use ERT.