Is There a Link Between Endometriosis and Cancer?

So after potentially years of physical and mental struggle, fighting through unexplained pain and countless doctor appointments, you have received your endometriosis (endo) diagnosis. Finally, you have some of the answers you’ve so desperately been waiting for. But wrapping your head around this condition can feel like coming up against one brick wall after another, given the amount of false information and rumours that have been spreading for generations. A quick google of the condition or words passed from a friend of a friend could leave you feeling more overwhelmed than you were to start with.

One particularly daunting word that comes up when researching endometriosis is cancer. Given the serious nature of the topic, it’s important to understand from the get-go that having endo does not necessarily increase your risk of cancer. Furthermore, there is no research to suggest that a genetic link between endometriosis and cancer exists. Still, it’s reassuring to be clued in on any potential association the two could have.

Let’s debunk the rumours and get to the bottom of some of the most intimidating questions together. Are endometriosis and cervical cancer kind of the same thing? To clear up any confusion between the two conditions, we can quickly break down what an endo diagnosis actually means. Endometriosis is a common gynaecological condition, affecting 1 in 10 women of reproductive age in the UK. The condition involves cells, very similar to endometrium (the tissues that line the uterus and break down to shed during your period), which grow elsewhere in places they shouldn’t. The cells typically form on or around areas in the pelvic region and can spread to the stomach, bladder, and bowel. Just like the endometrium, the cells respond to the hormonal changes, also breaking down during your period. But, unlike the endometrium, they aren’t able to shed as they have no exit out of the body.

This causes symptoms like chronic pain and inflammation, bowel and urinary problems, cysts and lesions, and in some cases, infertility. It is understandable that some might jump to conclusions about endometriosis, especially when they hear the words ‘cells’ and ‘hormones’. But the tissue-like cells that form due to endo are not cancerous and there is no research to suggest they have any relation. To set the record straight: endometriosis is not a form of cervical cancer. But what about endometrial cancer – are the two not related? While it’s true that the names sound very similar, endometrial cancer is only called this because it starts in the endometrium and not because of any link with endometriosis. Endometrial cancer is also known as uterine cancer and it is the most common cancer affecting women in the UK.

Symptoms of this type of cancer include abnormal vaginal bleeding, such as bleeding between periods and bleeding after menopause, pelvic pain or pressure, and pain during sex. Endometrial cancer is when cells of the endometrium grow out of control and form tumours, which can also spread to other parts of the body. While both endometriosis and endometrial cancer cause cells to grow where they shouldn’t, the process and result are very different. There is some early research to suggest that people with endometriosis may have a very slight increased risk of developing endometrial cancer. A study published in the International Journal of Gynaecological Cancer examined the association between the two conditions, tracking participants over a ten-year period.

The results were that 0.7% of participants who had endometriosis developed endometriosis, while in the control group (participants without endometriosis), 0.2% were diagnosed with endometrial cancer. The development of endometrial cancer is also far more likely to happen later in life, with the average age of diagnosis being 60 years old. This association may be due to the shared oestrogen stimulation and chronic inflammation that is caused by both conditions. However, more research is needed to fully understand this. It’s really important to remember that while there appears to be a subtle increased risk, the cancer was seen in less than 1% of those with endometriosis. While it might sound alarming you really don’t need to live in fear of endometrial cancer.

Are there increased risks with other types of cancer?

This is where the waters get a little murky. As of right now there is no conclusive evidence to confirm any more increased risks associated with cancer and endometriosis. There have been some studies done investigating a possible increased risk of developing breast cancer, however the results of these have been inconclusive.One study, published to the journal of Obstetrics and Gynecology, involved tracking 11,630 women in Denmark. No significant link was found overall between endometriosis and breast cancer. However, another study, published to the Oncology Letters journal, found that people diagnosed with endo at a younger age had a lower risk of breast cancer than the general population, but those diagnosed after the age of fifty may have a higher risk. The limited number of studies and the constraints of each means that any association found between breast cancer and endo is a weak one and no definite conclusion can be made.

There is a shocking lack of research into endometriosis, with less than 2.5% of UK publicly funded research going into reproductive health research overall. More clinical trials with long-term follow up are desperately needed to make sure an endo diagnosis answers your questions, and doesn’t pile on even more. Considering that 10% of women worldwide have endometriosis, it’s unquestionable that more needs to be done to not only research potential cancer risks, but to understand endometriosis better in the first place.

Most importantly, no matter what crazy story Dr Google might come up with, endometriosis is not a death sentence. In fact, doctors are recommended by the European Society for Human Reproduction and Embryology to inform those diagnosed with endo that endometriosis does not cause cancer – so there really is no cause for concern.If you have endometriosis, take the time to get to know what is normal for you. Tracking your symptoms is the best way to know when something isn’t quite right, which you can do with the log feature on our Syrona app. While it’s easy to get caught up in all the unknowns of endometriosis, put your focus on managing your symptoms and taking care of yourself as best as you can.

This article was written exclusively for Syrona by Niamh MacDonald