A major study of women who use the contraceptive pill has found that it does not increase the risk of breast cancer, contradicting previous research findings.
The Women鈥檚 Contraceptive and Reproductive Experiences (CARE) study involved 9,200 US women aged between 35 and 65. This group includes the first generation of women to have access to oral contraceptives. Approximately half of these women had breast cancer.
All were questioned in detail about their past use of contraceptive pills. The team found no link whatsoever between the use of an oral contraceptive, whether an older or newer generation Pill, and breast cancer.
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The new findings conflict with the results of previous study, published in 1996, which showed that women taking the oral contraceptive had a slightly increased risk of breast cancer.
This earlier study was a meta-analysis of 54 epidemiological studies. In an editorial in the New England Journal of Medicine, accompanying the new work, cancer experts at Johns Hopkins University say the 1996 paper was of 鈥渓imited value鈥�.
Other cancers
鈥淭he studies varied in the quality of their design and lacked the follow-up needed to determine whether there were long term effects of oral contraceptive use. In addition, only 40 per cent of the women had ever used oral contraceptives,鈥� write Nancy Davidson and Kathy Helzlsouer.
Leslie Walker, head of information at Cancer Research UK, says: 鈥淪tandard current thinking is that the Pill does slightly increase risk of breast cancer but that this risk stops after 10 years of cessation.鈥�
Other studies have shown that the contraceptive pill is associated with an increased risk of cervical and liver cancers, but decreased risk of endometrial and ovarian cancers. Breast cancer kills 400,000 women each year worldwide and 800,000 new cases are detected annually.
Journal reference: New England Journal of Medicine (vol 346, p 2025).