Endometrial Cancer and Obesity
Cancer of the womb lining is the cancer most strongly linked to excess weight, because fat tissue makes extra oestrogen - and losing weight lowers that risk.
Plain English
Patient-Friendly Explanation
Endometrial cancer is cancer of the lining of the womb (uterus), the part that sheds each month during a period. Body fat is not just storage: it can turn other hormones into oestrogen, and the more fat tissue you carry, the more oestrogen circulates. The womb lining grows in response to oestrogen, so a steady drip of extra oestrogen, especially without the balancing effect of progesterone, makes the lining thicken and raises the chance of cancer developing. That is why carrying excess weight is the strongest lifestyle-related risk factor for this cancer, and why the risk also rises with polycystic ovary syndrome and with years of irregular or missed periods. The warning sign that matters is any bleeding after menopause, or bleeding between periods or after sex before it - that always needs to be checked, not watched. The encouraging part is that this risk is modifiable: weight loss, treating irregular periods and using progesterone when appropriate all lower it, and weight-loss surgery has been shown to cut the risk substantially in women with severe obesity.
Medical
Clinical Definition
Endometrial cancer is the gynaecological malignancy most strongly associated with adiposity; pooled analyses place the risk of endometrial cancer at roughly 2 to 4 times higher in women with obesity compared with normal-weight women, with a dose-response relationship across BMI categories, and an estimated 40 to 50 per cent of cases attributable to overweight and obesity in high-income populations. The dominant mechanism is unopposed oestrogen: adipose tissue expresses aromatase and converts androgens to oestrone and oestradiol, while obesity lowers sex hormone-binding globulin, raising the free fraction of circulating oestrogen. Chronic anovulation, as seen in PCOS and in obesity-related menstrual dysfunction, removes the cyclical progesterone that normally restrains endometrial proliferation. Insulin resistance and hyperinsulinaemia contribute additionally by lowering SHBG further and by signalling through IGF-1 receptors, and obesity promotes a chronic inflammatory milieu in the endometrium. Most tumours are endometrioid adenocarcinomas of the oestrogen-driven type I pathway. Obesity also worsens outcomes independently of stage: it increases surgical and anaesthetic risk, lymphoedema and wound complications, and is associated with higher recurrence and mortality. Bariatric surgery is associated with a large reduction in endometrial cancer risk compared with medically managed obesity of equivalent BMI. Any post-menopausal bleeding, or abnormal pre-menopausal bleeding, requires prompt endometrial sampling.
Key Insight
Why It Matters
Because fat tissue makes oestrogen, weight is one of the few cancer risk factors you can actually change. If you have unexplained bleeding, irregular periods or a family history, tell us - and if you are carrying excess weight, the programme we build with you lowers this risk over time, not just the number on the scale.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: September 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
