Cancer & HRT- HRT ABC

Cancer and HRT is one of the most controversial topics around menopause.

Endometrial Cancer

Endometrial Cancer (EC) is one of the most common types of cancer in western countries. It is cancer of the womb. One of the most effective treatments for this type of cancer is hysterectomy. This is the surgical removal of the uterus, fallopian tubes, and ovaries. This prevents oestrogen production which can lead to premature menopause. Surgically induced menopausal symptoms tend to be more severe than naturally occurring symptoms because the onset is so sudden.  

Whilst EC is usually a post-menopausal condition, in many cases, patients could be premenopausal. Because of this, symptoms post treatment feel even more extreme. Although no solid scientific data exists to demonstrate that an HRT treatment is detrimental to EC cancer survivors, many clinicians are still reluctant in prescribing them. (European Journal of Cancer, 2014).

This creates a lot of confusion between women. Some of the patients are too young to be going through natural menopause. An early induced menopausal state creates several hormonal imbalances. Also, the risk of other pathologies such as severe osteoporosis, cardiovascular diseases, deep vein thrombosis and many others increase dramatically. Some people suffer from such severe menopausal symptoms, that HRT seems like a valid alternative.

So, which is the best choice here – trying to prevent cancer recurrence or trying to alleviate the symptoms? What are the numbers? 

Up ‘til now, the clinical community seems to agree that HRT is not a safe option for EC cancer survivors. However, there is not a lot of strong data out there.

Endometrial cancer has been widely monitored in the Million Women Study (Lancet 2005). This study shows that oestrogen-only HRT is not safe after EC but that combined therapy seems to be well tolerated. Other available studies do not show a decrease in survival among women with endometrial, ovarian or cervical cancer who use HRT. (The Obstetrician and Gynecolgyst 2014).

Using combined HRT therapy after EC cancer seems to increase recurrence in breast cancer or even predispose to it. Let’s consider also breast cancer carefully.

Breast Cancer

Breast cancer can be classified as receptor-negative (tumour does not respond to hormonal therapy) or receptor-positive (tumour does respond to hormonal therapy). The HABITS study is the largest study done on this. After this Randomized Controlled Trial (RCT) in 2004, the medical community established that HRT treatment wasn’t a safe option in breast cancer survivors.

What emerges from all these studies is that there is a lack of consistency in data…

…and some studies are not designed properly. An example of this inconsistency – there are cases of a negative outcome in cancer survivors who used HRT treatments but there is no strong indication that this is more likely compared to patients without a history of cancer.

The HABITS study has been interrupted for safety reasons as has the Stockholm study – which failed to replicate HABITS study findings. The Stockholm study shows that HRT therapy seems to increase cancer occurrence in healthy women. But it makes little or no difference in cancer survivors. These two large studies would seem to contradict each other.

Women should be made aware that the increased risk of developing breast cancer through HRT is less than the risk of developing breast cancer from being overweight or having a glass or two of wine each night.

Benefits vs Risk

A review published in 2016 in Nature Reviews Endocrinology, aimed to analyse all the available data to give a precise overview of the situation. What emerged is that there are a lot of benefits of HRT as well as some risks. Benefits can include delaying the onset of cardiovascular diseases, reducing the risk of deep vein thrombosis, and osteoporosis. The study takes into account the increased risk of cancer, stating that personalised therapy should always be taken into account.

One of the last updates from the British Menopause Society declared that the risk of breast cancer recurrence in women undergoing HRT has been underestimated. This was supported by various scientific papers. This study considered most of the variables that weren’t calculated in the previous studies. It concluded that patients undergoing combined HRT therapy have a 2.7% higher chance of getting (or getting back) breast cancer and that the risk increases with the duration of HRT treatment.

There is no association between oestrogen-only HRT and an increased risk of breast cancer.

Cancer and HRT Conclusion

The only thing we can conclude with any certainty is that there is still not enough evidence provided by properly designed studies, to demonstrate that HRT treatment increases the recurrence of cancer to any great extent.

HRT can drastically improve the quality of life of a person. So this is also a big deciding factor. Cancer survivor patients should consider the lowest possible dose of HRT for the shortest period of time, once all alternatives have been explored, and taken under strict medical control.

People should make informed decisions about HRT. But for this to happen, they need to know all the risks and benefits. This should give them the knowledge to choose wisely what is best for them.

There is no one size fits all answer here. This treatment should be personalised to the person’s needs because there are so many contributing factors (age, genetics, lifestyle) that effect outcomes