Women have long been told if they take the contraceptive pill they may be at higher risk of cervical cancer or breast cancer. But according to the new research from the University of Aberdeen (Scotland), those women who have taken the oral contraceptive pill are protected from three common cancers for as long as 30 years.
Researchers at the University of Aberdeen said those who have used the pill, which has been linked to depression, were about 34 percent less likely to develop ovarian and endometrial (lining of the womb) cancers, and 19 percent less likely to suffer bowel cancer than women who had never taken the oral contraceptive.
The world’s longest running study led by the team of Aberdeen University in the UK into the effects of taking the contraceptive pill also looked that using the pill during their reproductive years and found it does not increase the risk of other cancer risks later in life, disappearing completely five years after they stopped taking the contraceptive pill. (the time when more cancers occur).
By the time women have gone through the menopause, those who have taken the Pill in the past are at no additional risk of any types of cancer. The protective mechanism is believed to be because women on the contraceptive pill are not producing any eggs. The normal process of egg release triggers cell damage and repair that raises the risk of tumor development.
The Oral Contraception Study was established by the Royal College of General Practitioners in 1968, seven years after the pill was first introduced into Britain on the NHS. The Oral Contraception Study has followed 46,000 women for up to 44 years. This has created more than 1.2 million ‘woman-years’ of observation to investigate the long-term health effects of oral contraceptives. They were also about a fifth less likely to develop lymphoma, a less common cancer of the immune system.
Lead researcher, Dr Lisa Iversen, from Aberdeen University said: “If you have used the pill during your reproductive life, you will get this protective effect.”
“What we found from looking at up to 44 years’ worth of data, was that women are less likely to get colorectal, endometrial and ovarian cancer.”
“So the protective benefits from using the pill during their reproductive years are lasting for at least 30 years after women have stopped using the pill.”
The researchers calculated that taking the contraceptive pill for any length of time lowered the cases of endometrial cancer by 34 percent, ovarian cancer by 33 percent and bowel cancer by 19 per cent. It means that for every three women who would have developed ovarian or endometrial cancer, one has been protected by taking the pill. And for bowel cancer around one fifth of cases were prevented through oral contraception.
Around 35,000 women are diagnosed with the three conditions each year. And out of those, around 18,000 women a year are diagnosed with bowel cancer, killing almost half. Endometrial or womb cancer affects more than 9,000, claiming over 2,000 lives annually and 7,400 women are diagnosed with ovarian.
“These results from the longest-running study in the world into oral contraceptive use are reassuring,” said lead author Dr Lisa Iversen.
“They provide strong evidence that most women do not expose themselves to long-term cancer harm if they choose to use oral contraception; indeed, many are likely to be protected.”
“Because the study has been going for such a long time we are able to look at the very long-term effects, if there are any, associated with the pill.”
“Specifically, pill users don’t have an overall increased risk of cancer over their lifetime and that the protective effects of some specific cancers last for at least 30 years.”
The combined contraceptive pill works by artificially raising the levels of the two sex hormones oestrogen and progesterone, which cause changes in the reproductive system and stop the ovaries from ovulating. Scientists say this “reduction in ovulation” activity may explain the drop in ovarian and endometrial cancer risk. Another theory is the hormones in the pill limit cell growth and division, which can result in mutations that trigger cancer.
Professor Helen Stokes-Lampard, Chair of the Royal College of GPs, said: “Millions of women who use the combined oral contraceptive pill should be reassured by this comprehensive research that they are not at increased risk of cancer as a result – and that taking the pill might actually decrease their risk of certain cancers.
The new research, which has received funding from bodies including the Imperial Cancer Research Fund, Medical Research Council and the British Heart Foundation, published its latest findings online in the American Journal of Obstetrics and Gynaecology.