Women who have ever used the Pill face a slightly increased risk of developing breast cancer, according to one of the largest studies on oral contraceptive use, the 3rd European Breast Cancer Conference heard on Friday, March 22.
The women’s risk rose by just over a quarter (26%) compared with women who had never used the Pill. Women who were still using the Pill had an increased risk of just over a half (58%) compared with never-users. The highest increased risk was amongst women aged 45 or over who were still using the Pill – their risk of developing breast cancer was nearly one and a half times (144%) the risk of never-users.
However, Dr Merethe Kumle, the epidemiologist leading the research said that it was important not to over-state this risk. “Oral contraceptives have a lot of advantages as well as disadvantages,” she said. “The total number of deaths from any cause amongst women who use oral contraceptives is likely to be lower than women who have never used the Pill – just as we have seen with hormone replacement therapy. The Pill has made it possible for women to decide when and how many children they will give birth to – something which has revolutionised women’s lives and is an important issue in women’s rights.”
The study revealed no increased risk among women who used oral contraceptives before the age of 20 or before their first full-term pregnancy.
Dr Kumle, from the Institute of Community Medicine in Tromso, Norway, collaborated with researchers in Sweden and France to study data from the “Women’s Lifestyle and Health Study” carried out in Norway and Sweden.
At the start of 1991/1992, 103,027 women, aged between 30 and 49, completed a questionnaire that included questions on hormonal contraceptive use and other lifestyle characteristics. The researchers followed them through to December 1999 and found that in that time 1,008 cases of breast cancer had been detected. Most of the women who had taken the Pill, had used the more modern brands that are currently prescribed by doctors.
Dr Kumle said: “I think the results from this study of Norwegian and Swedish women are very interesting and confirm results from earlier studies of oral contraceptive use. Although the rate of women participating in the study was not very high at 55%, our follow-up is complete and the women we were studying were relatively young. It is clear that oral contraceptives increase a woman’s risk of developing breast cancer, particularly when they are used in the later period of reproductive life.
“It is important to remember that the absolute risk of a woman developing breast cancer under the age of 40 is very low. Modern oral contraceptives have much lower hormone doses in them than the older ones which did cause an unacceptably high number of adverse effects.
“The incidence of breast cancer in Western countries has been increasing in the past 30 years, but there appear to be a number of reasons for this. The use of oral contraceptives is one reason, but girls tending to start their periods earlier, women having fewer and later births, later menopause and overweight after the menopause are all reasons too.
“We found a slightly increased risk of breast cancer among users of the Pill, but it is important to underline that young women using the Pill are not playing hazard with their health. As contraception, the Pill should still be the drug of choice for young women.”
Materials provided by Federation Of European Cancer Societies. Note: Content may be edited for style and length.
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