Endometrioid cancer of the ovary and womb

Endometrioid describes tissue that looks like the endometrium, the womb lining. In the womb itself it is by far the most frequent form. In the ovary it forms a minority of epithelial cancers, often linked in origin to endometriosis, a condition in which womb-lining-type tissue grows outside the womb.

Cancer Research UK also lists endometriosis and diabetes among conditions that raise ovarian cancer risk, and NHS information on causes names endometriosis as well. Having endometriosis does not mean cancer will follow; the great majority of people with it never develop ovarian cancer.

The leading symptom is abnormal bleeding: spotting or bleeding after the menopause, heavy periods that are unusual for you, bleeding between periods, or a change in discharge. The NHS asks anyone with these to see a GP, and an urgent referral may follow, which does not mean cancer has been confirmed.

Tests normally include a pelvic ultrasound and a biopsy of the womb lining, often with a camera (hysteroscopy). Surgery is the main treatment: removal of the womb and cervix, usually with the ovaries and tubes. Lymph node assessment, radiotherapy, chemotherapy or immunotherapy follow according to risk. Cancer Research UK notes that recovery is usually a few days in hospital followed by a few weeks at home, with full recovery taking several months.

Symptoms match other ovarian cancers: persistent bloating, pelvic pain, feeling full quickly and urinary changes. The pathway is a CA125 blood test, an ultrasound, a hospital referral where indicated, then CT and tissue diagnosis.

Ovarian endometrioid cancers are often diagnosed at an earlier stage than high-grade serous cancer. Treatment is surgery, with carboplatin-based chemotherapy depending on stage and grade. Low-grade disease confined to the ovary may need surgery alone, while high-grade or advanced disease follows the same route as other epithelial ovarian cancers, including genetic testing and consideration of maintenance treatment.

Macmillan describes four molecular groups used in womb cancer: MMRd, p53abn, POLE and NSMP. Endometrioid tumours can fall into any of them, and the group helps predict behaviour and whether extra treatment after surgery is needed.

Mismatch repair testing also screens for Lynch syndrome, an inherited condition that raises the risk of womb, ovarian and bowel cancers. If a tumour shows loss of mismatch repair proteins, further tests may lead to a referral to clinical genetics, with implications for relatives.

Occasionally, endometrioid tumours are found in the womb and the ovary at the same time. In many people these are two early, separate cancers, which has a better outlook than one cancer that has spread. Pathologists compare the tumours in detail, including molecular features, to decide.

The answer changes treatment: two low-stage cancers may need surgery alone, whereas a single metastatic disease would be managed as higher stage. This is one reason review by a specialist gynaecological pathologist and an MDT discussion are standard.