You can quickly become worried by reading about the studies on how oral contraceptives affects the body and brain. A new Danish study shows that the pill increases the risk of breast cancer but reduces the risk of ovarian cancer. The researchers behind the studies conclude that it is equally important to remember that most things in life entail risk. However, in weighing up the pros and cons to make the right personal decision it is worth knowing what the risks are.
In recent years, such headlines as “Pioneering study: the pill can lead to suicide” and “Contraceptives increase the risk of blood clots” have been frontpage news in the media in Denmark. Recently, Danish researchers from Rigshospitalet revealed that using hormonal contraceptives such as the pill and the hormonal coil increase the risk of breast cancer.
“For all types of oral contraceptives as a whole, women have a 20% greater risk of developing breast cancer while using these products. As soon as they stop, the risk begins to fade and is typically gone after 5 years. However, this needs to be seen in a wider perspective associated with all the other risks and benefits associated with a drug. Then, it may well be reasonable to take a risk if several other benefits compensate for this,” explains a main author, Øjvind Lidegaard, Clinical Professor, Rigshospitalet, Copenhagen.
New products entail the same risk
The researchers from Rigshospitalet followed 476,000 women 15–49 years old an average of 8.3 years from 1996 to 2013 through the Danish National Prescription Registry and Danish National Patient Registry. In the population as a whole, 55 of 100,000 women 15–49 years old who have never used hormonal contraceptives develop breast cancer each year. Among the women who used hormonal contraceptives, 13 additional women per 100,000 (total 68 per 100,000) developed breast cancer.
“We can also see how much the risk increased in relation to how long women used the product. Women taking the pill for 1 year have a small percentage increase, and then it increases virtually linearly. So women who have used hormonal contraceptives for 10 years have a 46% increase in risk compared with the women who have never used them. The risk is therefore not several times greater, but this risk still has to be factored into the equation in relation to the benefits and disadvantages of these products.”
Breast cancer is the most common type of potentially fatal cancer among women, and since 40% of the women of reproductive age in Denmark use hormonal contraceptives, the study is important, especially since the existing studies were conducted in the 1970s and 1980s. Since then, many new drugs have been launched, and the researchers therefore wanted to determine whether the new drugs such as the mini-pill and hormonal coil have different effects than the older products.
In many areas, we have been able to find differences between the pill and the hormonal coil. If women switched from the pill to the hormonal coil, the additional risk of blood clots disappeared completely, so we were curious whether this would apply to the risk of developing breast cancer. Unfortunately, this was not the case, with the risk of breast cancer being pretty much the same for both the hormonal coil and the pill.
Reasons for concern
The new study was the latest of several studies by these Danish researchers. In 2015, they showed that women who took the newest types of contraceptive pills had twice the risk of developing a blood clot than those who took a slightly older pill. Finally, another study showed that women who use hormonal contraceptives have more than twice the risk of attempting suicide and three times the risk of carrying it out.
“I usually say to the patients I talk with that everything has a risk, also their impending operation, but that the greatest risk they have faced today was riding their bicycle to the hospital. When we cycle, the risks are compensated for by all the benefits of cycling: fun, health, getting there more quickly and the like. So we did not conduct these studies to scare people away but rather to make them wiser and provide them with a basis on which they can decide whether they think taking this product makes sense because the benefits outweigh the risks.”
Øjvind Lidegaard and his colleagues are collaborating with British researchers on studying the risk of developing cancer associated with using hormonal contraceptives. Denmark is unique because the researchers can link the Danish social security number (CPR number) – without identifying the individual person – with the information in the Danish National Prescription Registry, Danish National Patient Registry and other registries. This means that they can study the whole population at one time. The researchers are now mapping the risks associated with 20 types of cancer.
This is a work in progress, and breast cancer was the first. Fortunately, taking the pill reduces the risk of other types such as ovarian cancer. So we do not find an increased risk every time we examine something. Often one product can reduce the risk of developing one type of cancer while increasing the risk of another. This is not contradictory.
In addition to helping individual women make informed decisions about using hormonal contraceptives, Øjvind Lidegaard also hopes that the research may contribute to helping doctors in their daily practice.
“Clearly, since we find that the risk of depression and suicide increases as much as our study shows, someone sitting in front of you who has had depression recently or has attempted to kill themselves in the past 6 months may put this in perspective. If this is the case, then we could give some extra thought before handing her a prescription that might increase the risk of suicide by 100%.”
“Contemporary hormonal contraception and the risk of breast cancer” has been published in the New England Journal of Medicine. In 2014, the Novo Nordisk Foundation awarded Øjvind Lidegaard a grant for the project The Impact of Hormonal Contraceptives on Cancer Risk, on Survival after Diagnosis of Cancer, and on Total Mortality.