Tamoxifen does not reduce the risk of lung cancer in women

Abstract

7212 Background: Mounting evidence indicates that women have a different susceptibility to lung cancer than men. In particular, female never-smokers are more likely than male never-smokers to develop lung cancer. Moreover, women are more likely to be diagnosed with adenocarcinoma than are men. Coupled with the localization of estrogen receptors alpha and beta to lung cancer cells, gender differences in incidence point to a possible role for circulating estrogens in lung tumorigenesis. We sought to determine if use of the anti-estrogen tamoxifen decreases the risk of lung cancer. Methods: We examined incidence rates of second primary lung cancers by categories of tamoxifen treatment among women enrolled in randomized ECOG adjuvant breast cancer trials. Overall, there were 15,875 women in 14 studies from 1978–2002. The duration of tamoxifen treatment varied by study and was alternately categorized as ≤ 1, ≤2 or ≥5 years. Results: We identified 55 second-primary lung cancers over 97,225 person-years of follow-up. 27 second-primary lung cancers occurred among 6,478 women who did not receive tamoxifen versus 28 lung cancers among the 9,397 women who received tamoxifen of any duration. Compared to women without tamoxifen treatment, those treated for fewer than two years had an age-adjusted relative risk for lung cancer of 1.13 (95% CI 0.52–2.32). Similarly, among women treated with tamoxifen for ≥5 years the relative risk for subsequent lung cancer was 0.80 (95% CI 0.40–1.57). Conclusions: We did not observe a strong association between tamoxifen treatment and the risk of second-primary lung cancer in a sample of women who had received tamoxifen as adjuvant therapy for breast cancer. The results are similar to those previously reported (Fisher, JNCI 1998). However, the potential estrogenic activity of tamoxifen may argue for evaluating adjuvant breast cancer trials of aromatase inhibitors for incident second primary lung cancers. No significant financial relationships to disclose.