The endometrium is the lining of the uterus. It is subject to a process of cyclical change during the fertile years of a woman’s life. The majority of cancers that occur in the body of the uterus (womb) are endometrial cancers, mostly adenocarcinomas.
Incidence and survival rates
Endometrial cancer is the sixth most common cancer in women worldwide (and the 14th most common cancer overall). Around 320,000 new cases were recorded in 2012.
It is mainly a disease of high-income countries, where the highest incidence of endometrial cancer is in North America, and Central and Eastern Europe; and the lowest incidence in Middle and Western Africa.
Age-adjusted rates of endometrial cancer are increasing in countries undergoing transition from low- to high-income economies; although there is no clear, overall trend in high-income countries.
Endometrial cancer often produces symptoms at relatively early stages, so the disease is generally diagnosed early. The overall 5-year survival rate is relatively high, although it is lower in middle- than in high-income countries. For example in the US, the 5-year relative survival rate (which compares the 5-year survival of people with the cancer to the survival of others the same age who don’t have cancer) for all endometrial cancer cases is about 69%.
Endometrial cancer accounts for just under 1 per cent of all cancer deaths (2 per cent of cancer deaths in women).
Lifestyle factors and endometrial cancer risk
In this report from our Continuous Update Project (CUP) – the world’s largest source of scientific research on cancer prevention and survivorship through diet, nutrition and physical activity – we analyse global research on how certain lifestyle factors affect the risk of developing endometrial cancer. This webpage forms part of the World Cancer Research Fund/American Institute for Cancer Research Third Expert Report Diet, Nutrition, Physical Activity and Cancer: a Global Perspective.
Findings on endometrial cancer
There is strong evidence that:
- being overweight or obese INCREASES the risk of endometrial cancer
- being tall INCREASES the risk of endometrial cancer
- glyceamic load INCREASES the risk of endometrial cancer
- physical activity DECREASES the risk of endometrial cancer
- consumption of coffee DECREASES the risk of endometrial cancer
There is some evidence that:
- sedentary habits might increase the risk of endometrial cancer
Other causes of endometrial cancer
In addition to the findings on diet, nutrition and physical activity outlined above, other established causes of endometrial cancer include:
- life events
Not bearing children and a late natural menopause (after the age of 55) both increase the risk of endometrial cancer. The reverse also applies: bearing children and early menopause reduce the risk of endometrial cancer.
Oral contraceptives, which contain either a combination of oestrogen and progesterone, or progesterone only, protect against endometrial cancer. Oestrogen-only hormone replacement therapy is a cause of this cancer and is normally only prescribed to women who have had a hysterectomy. Tamoxifen, a hormonal therapy used for breast cancer, can also cause endometrial cancer.
- family history
Women with a family history of endometrial or colorectal cancer have a higher risk of endometrial cancer. Lifetime risk of endometrial cancer in women with Lynch syndrome mutations MLH1 or MSH2 is approximately 40 per cent, with a median age of 49. Women with MSH6 mutations have a similar risk of endometrial cancer but a later age of diagnosis.
Type 1 endometrial tumours are oestrogen driven, account for around 80 per cent of endometrial cancers, and have a favourable prognosis. They follow a clear development pathway, starting with endometrial hyperplasia (an increase in the number of cells), and are relatively well differentiated. Type 2 tumours are less common, accounting for around 10 per cent of endometrial cancers. Most are associated with endometrial atrophy (wasting), tend to metastasise, and have a less favourable prognosis.
Many cases of endometrial cancers are reported in women who have no recognised risk factors – such as those that might disrupt endocrine (hormone) processes. Some studies have shown that polycystic ovary syndrome and insulin insensitivity (or resistance), which are both components of metabolic syndrome, may play a role in the pathogenesis of endometrial cancer, perhaps through hormonal disruption. The tumour-suppressor gene PTEN is also involved in the development of endometrial cancers.
Full references and a summary of the mechanisms underpinning all the findings can be found in the endometrial cancer report.
How the research was conducted
The global scientific research on diet, nutrition, physical activity and the risk of endometrial cancer was systematically gathered and analysed, and then independently assessed by a panel of leading international scientists in order to draw conclusions about which of these factors increase or decrease the risk of developing endometrial cancer.
Published findings in peer-reviewed journals
Selected findings from this report have been published in peer-reviewed journals. Details of the papers and links to the abstract in PubMed are below:
Anthropometric factors and endometrial cancer risk: A systematic review and dose-response meta-analysis of prospective studies. Aune D, Navarro Rosenblatt D, Chan DS, Vingeliene S, Abar L, Vieira AR, Greenwood DC, Bandera EV & Norat T. Ann Oncol. 2015; 26(8): 1635-8. Abstract
This webpage is a summary.
For much more, download the full chapter.