Do Oral Contraceptive Pills Cause Cancer? The link between Oral Contraceptives and Cancer


The link between Oral Contraceptives and Cancer – And of course Angelina Jolie…

Oral contraceptive pills have always been a subject of discussion. They have been defined as a revolution for women sexuality and feminist movement while it is also claimed that they cause infertility, increase the risk of cancer in long term use.

This last claim has been discussed for long years in the entire world.

Then can we use these long time speculated oral contraceptives in purpose of birth control? The answer may be “noo why did you think that” briefly and clearly.

In fact, according to TNSA 2008 data, only %5 of married women use these pills in purpose of prevention of getting pregnant (1).

Although our vice president said that “we will break the games on birth control” (2), but our people still use the ancient method we call “pulling out”. As you may understand, birth control is managed by an understanding of “fend for yourselves”

Therefore, it is very arguable which game we will break, in what grounds and environment.

Anyway, let’s focus on the subject and try to seek answers to the question why we use these pills apart from this purpose.

We gynecologists love oral contraceptive pills as they are the safest harbor in certain topics related to gynecological diseases that put us in trouble. They are very simple and efficient drugs.

Doğum Kontrol Hapları ve Kanser Riski Prof. Dr. Süleyman Engin Akhan

For example, we use these pills for regulation of irregular menstrual bleedings, relieving patients of the problem called endometriosis, curing hairiness and acne problems, stabilizing menstrual cycles with the purpose of IVF treatment.

Actually my friends, we use these pills for deceiving the hormone called FSH whicj is secreted from the hypophysis in the brain which invokes your ovaries and saying “dude you do not need to be secreted, these places are filled with estrogen” thus stopping the function of your ovaries for a while.

As a result, your ovaries stop working for a while and go to sleep. How deceptive we are aren’t we?

Do not worry, your ovaries get back to normal functions in approximately 3 months when you quit using the drug. “Oral contraceptives cause infertility” is just a false legend.

However, %1 of all women get into early ovarian failure (early menopause as you know it). I am sorry but this rate is valid for the entire world and %1 is a serious rate. As a result, women in this group who use oral contraceptives face the bitter reality when they quit using the pills. The word spreads quickly and the claim that oral contraceptives cause infertility spreads out.

Then all those things said for these pills, are they all lies? Let me answer this with famous quote of Winston Churchill; “A lie gets halfway around the world before the truth has a chance to put its pants on”.

As a result, they do not cause cancer, period.
But the link between cancer and oral contraceptives exists. There it is, another “period”.

One way or another, there is a relation between oral contraceptives and breast and genital cancers (cervical, ovarian and uterine cancers). What you need to understand is the size of this relation. Are they lovers? Are they enemies? Or are they just friends?

I. The relation between Breast cancer and oral contraceptives: Tough topic

It is very difficult to evaluate the risk factors that cause breast cancer. They are too many and those many factors which are related to each other play a role in development in breast cancer, thus making it very difficult to evaluate the effect of oral contraceptives by isolating them from all those factors.

Firstly, cancer does not develop suddenly. Development of breast cancer is a process that takes long years.

For example; weight is a risk factor on its own. After the age of 18, being above 27 kg increases your risk for breast cancer in menopausal period is increased two times while being above the age of 35 and having no births increases your risk 3 times in social basis (3,4).

I know, what does social basis mean? Is it increased or not? Just say what you have to say. Then lpelase the long note at the end of the article in order to understand numeric plays before I jump in the subject. I put the statistical knowledge you should know for understanding the subject in order to keep the topic from distraction.

At this point, I want you to know that these rates I told below are in the categorization of “relative risk” and this risk does not reflect your actual personal risk rates.

Briefly, it is very difficult to evaluate the relations between oral contraceptives and cancer in academic point of view. In the duration until development of cancer, woman is exposed to many factors which increase the risk of breast cancers more than oral contraceptives.

The problem is not just these factors. In the same time, in this long process, the containments, doses etc. of these drugs are all changed. Therefore, it is very important to select the studies for learning if oral contraceptives increase the risk of breast cancer.

As I told you, the duration is long. Then, the studies investigating the risk of breast cancer after the age of 50 including the women who use oral contraceptives after 1972, but 1974 is better, would be ideal.

In fact, the estrogen doses in these pills are reduced to 30 – 35 pg, which is the level of today. The age is also important, as our triangulation point should be the cancers which occur after the age of 50. Because, the cancers which develop in early ages occur in different events and familial, genetic risk factors get into play.

For example, the study of Suzan Folger published in 2007 is an important research at this point of view. Researcher investigated the question if the breast cancer risk increases in women who use oral contraceptives in shorter durations (5).

At the end of the study, it had been found out that the risk of breast cancer in those who use oral contraceptives in durations shorter than 6 months does not increase, but if breast cancer occurs before the menopause, the risk of breast cancer is increased, if it occurs in menopause, the risk is not increased but reduced. I will get back to this reduction subject later.

The answer to the question “Why do they increase the risk in those who develop breast cancer in early ages?” lies in the risk factors.

In those who develop breast cancer in early ages, there are many risk factors which are more dominant than oral contraceptives. These factors are; history of breast cancer in first degree relatives, having menstruation before 12, having no childbirths and this list goes on and on.

Our aim for evaluating the relation between oral contraceptives and breast cancer would be the study which gives the right information, “the study investigating the risk of breast cancer after the age of 50 including the women who use oral contraceptives after 1974”, right?

Is there any study like that? Yes there is! Only one, which is only published in 2007. This is a metaanalysis, which means many studies are investigated and the qualified ones are evaluated, after that the data is shared (6).

Let’s give all the numbers then. Gierisch et al. read and evaluated 6476 studies which investigate the relations between oral contraceptives and breast cancer and found only 44 of them valuable!! How? Studies are many but the number of real and valuable researches is too few.

AS a result, as I told before, use of oral contraceptives increase the relative risk of breast cancer in limits. Relative risk of women who use is only 1.08! This is the amount of the risk.

However, in the series of Prof. Dr. Vahit Özmen including the data of Turkish women which is I believe the largest in our country, RR was found to be 1.46 in women who have BMI above 25 while RR was 3.06 (three times more) in women who gave birth after the age of 35 (4).

Interestingly, in the same study, it was found out that not using the oral contraceptives reduces the risk of breast cancer to half (RR 0.59) just as in Folger’s study. Really, the studies are towards this direction. The reasons for this are not the subject of this article, therefore I do not want to talk about it more.

Last words; the risk increase in our girls who use oral contraceptives is such low that when you consider other factors it is very meaningless. It is in a level that would not affect me prescribing and you using these pills.

I get very sad when I see the expression of mothers when I give these drugs to young girls in order to suppress the ovaries, not as a contraceptive methods

Let’s get to other genital tumors with the wish that this writings relieved the mothers a bit.
I promise others won’t be as long and boring.

II. Oral Contraceptive Pills and Cervical Cancer

Oral contraceptives increase the risk of cervical cancer! But, a very biiiiig “but”; this increase depends on two basic rules:
1. Woman who uses oral contraceptives MUST carry the HPV virus.
2. She must use these pills for AT LEAST 5 years.

HPV yakışıklı Prof. Dr. Süleyman Engin Akhan

If the woman does not carry HPV, there is no capability of oral contraceptives for increasing the risk of cervical cancer. Besides, she must use them for at least 5 years (6).

The answer to why they increase the risk is unclear. Namely, the mechanisms are not known. There were some theories about E2 gene location in genetic structure of HPV around 2004-2005 but they were not proven. As a result, if you do not carry the virus there is no problem, if you carry it you can use it for 2-3 years.

By the way, there is no relation between oral contraceptives and precursors of cervical cancer (CIN1, CIN2). At least, keep your mind at ease in this point. If you ask me what I do in my practice; I ask my patients to quit using the drugs if she have been using them for over 5 years and I determined CIN1/CIN2.

As you can see, we are very clear about the relation between oral contraceptives and cervical cancer.

III. Oral Contraceptives and Uterine Cancer

I will be shocked if I ever see our great professors saying that oral contraceptives prevent cancer in the media. Yes, the risk of uterine cancer is REDUCED TO HALF compared to those who do not use them (6).

The rates of prevention increase as the duration of use increases. Although it is reduced a bit when the drug is quit, it keeps on for at least 15 years.

Another topic we are clear about

IV. Oral Contraceptives and Ovarian Cancer

There is another organ in which cancer is prevented by oral contraceptives. Use of oral contraceptives REDUCES the risk of ovarian cancer for sure, depending on the duration of use. This preventive power of oral contraceptives increases proportional to duration of use and keeps on for at least 20 years (7).

An exception to this effect is the ovarian cancers we call mucinous type and borderline type. The effect is less clear in these cellular types. There is no preventive effect in the sub cellular type of ovarian cancer called borderline mucinous, which is very rare.

Therefore, in those who have BRCA 1 and 2 genetic mutation who have the highest risk for breast and ovarian cancer, they must be used in order to protect the individual in ovarian cancer! (8)

Let’s detail this last word a bit and get to the title.

I think you all know Angelina Jolie. The actress, who became an idol of sexuality with her marvelous breasts, got her breasts removed without hesitation!
The reason was that she was carrying BRCA 1 mutation.

The risk of a woman who carries BRCA 1 mutation for breast cancer is %80, which is not relative risk. Additionally, the risk of ovarian cancer in those with BRCA 1 is %60. Clear as that.

“Protective mastectomy”, advised for those who carry this mutation, is the surgery for removing the mammarial tissue in order to prevent cancer. Then what are we going to do for the ovaries?

Hypothetically she is married, 30 years old. She wants children but has BRCA 1. In that case, we ask her to have children right away. If she is not married and does not want children yet, we make her use oral contraceptives for sure.

Besides, the risk of these pills causing cancer is meaningless clinically as I told before, more importantly the risk of a woman with BRCA mutation is that high, the preventive risk of oral contraceptives against ovarian cancer becomes very important.

As a result, oral contraceptives provide certain preventive effects against ovarian cancer.

shutterstock_96168842 Prof. Dr. Süleyman Engin Akhan

I hope this information becomes useful; because such information is shared in life, for example in TV or radio, people cannot evaluate where the talk is going to whoever is talking about it.

That information may become very devastating for ordinary people especially psychologically.

It is very important to share true knowledge understandably in my job.
I believe that the lines above may be very useful for you.

Happy Sundays

With love and respect
Glad to have you…

A very looong footnote

Relative Risk
It is defined as this in Wikipedia: “relative risk (RR) is the ratio of the probability of an event occurring (for example, developing a disease, being injured) in an exposed group to the probability of the event occurring in a comparison, non-exposed group. It is calculated as the rate of occurrence risk between those who are exposed and who are not (9).”

Now let me try to make it clear. In the studies conducted for finding out if a factor is increasing the cancer risk in a certain community, two groups are compared called study group and control group.

As a classical example, you are trying to understand the cancerous effect of radiation. You observed 100 people who were exposed to radiation and you found out that 20 of them got blood cancer 10 year later. Let’s pretend that 1 person got blood cancer in the control group which were not exposed to radiation in the same duration. Then we can say that radiation caused 20 times more risk for cancer in that society from the ratio 20/1=20.

However, this is not a personal risk of someone. Namely, it does not mean that you will have 20 times more risk for blood cancer in personal basis just because you are exposed to radiation. 20 times risk is a social based risk.

Let’s explain this with a real example. WHI study is an important study investigating the relation between hormone therapy and breast cancer in menopausal women. According to this study, the relative risk in women in menopause who use estrogen+progesterone drugs for 5 years is 1.24. Thus, the risk is increased %24.

Now is you are having hormone therapy, does this mean your personal risk is increased %24? NO. In 2003, some of our professors got up to main news programs of television and said that one out of four women who uses hormones in menopause get breast cancer. Shame!

Then how much does your risk increase according to WHI? In case of 1000 women using estrogen + progesterone combination for 5 years, only 1, yes only one woman gets breast cancer due to this drug. In fourth year, this risk is the same with a woman who do not use this drug!

4. Ozmen V. Breast cancer risk factors in Turkish women–a University Hospital based nested case control study. World J Surg Oncol. 2009; 7:37.
5. Folger S.G. Risk of breast cancer associated with short-term use of oral contraceptives.Cancer Causes Control. 2007 Mar;18(2):189-198
6. Gierisch J.M. Oral contraceptive use and risk of breast, cervical, colorectal, and endometrial cancers: a systematic review. Cancer Epidemiol Biomarkers Prev. 2013; 22(11):1931-1943.
7. Havrilesky L.J. Oral contraceptive use for the primary prevention of ovarian cancer.Evid. Rep. Technol Assess (Full Rep). 2013; (212):511-514.
8. Cibula D. Hormonal contraception and risk of cancer. Hum Reprod Update. 2010; 16(6): 631-650.
9.öreceli risk