Oral contraceptives: not associated with lung cancer risk

8 Apr 2015

A large prospective study of lung cancer, the Women's Health Initiative Studies, found no strong associations between lung cancer risk and a wide range of reproductive history variables. It only revealed weak support for a role of hormone use in the incidence of lung cancer.

Given the gender differences in lung cancer prognosis and survival rates, there is a need to understand the potential role of reproductive factors and hormone use in determining lung cancer risk in women.

Clinical trial with more than 160.000 participants and a 14-year follow-up

The Women's Health Initiative Observational Study and Clinical Trials enrolled a geographically and ethnically diverse cohort of 161,808 postmenopausal women age 50-79 years between 1993 and 1998 at 40 centers across the United States. Reproductive history, oral contraceptive use, and hormone therapy replacement was evaluated in the 160,855 women eligible to be included in the analysis. Incident lung cancer was observed in 2,467 and the median follow-up was 14 years.The results show that:

  • Women with previous use of estrogen plus progestin (< 5 years) were at a slightly reduced risk for lung cancer.
  • Increasing age at menopause trended towards reduced risk whereas increasing number of children trended towards increased risk.
  • Those who were age 20-29 at the birth of their first child had reduced risk of non-small cell lung cancer (NSCLC), but not all lung cancer.
  • Risk estimates for hormone therapy usage and previous surgery to remove both ovaries varied with tobacco exposure history



Complex connection between cigarette smoking, estrogen, genetic susceptibility and lung cancer

The authors conclude «the overall results presented by our study suggest that oral contraceptives and hormone therapy use are not associated with risk of lung cancer." The lead author Ann G. Schwartz, Deputy Center Director, Karmanos Cancer Institute, Wayne State University and member of IASLC, cautions that "questions remain about estrogen and lung cancer risk that will not easily be answered by studies focusing on hormone use” and emphasizes that “the interplay between cigarette smoking, estrogen, genetic susceptibility and lung cancer is complex and continued study is necessary to tease apart these relationships."


Source: Science Daily
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