Cancer that arises from the endometrium (innermost lining of the uterus)

Aetiology

• Peak incidence: 50-60 years, uncommon under 40
• In young women, consider underlying predisposition e.g. PCOS or Lynch syndrome

Risk factors

• Prolonged period of anovulation e.g. early menarche/late menopause, low parity, PCOS
• Obesity
  • Excess risk is associated with the endocrine and inflammatory effects of adipose tissue

Pathophysiology

Endometrioid and mucinous carcinoma (type 1 tumours) - 80%

• Atypical hyperplasia is the precursor, related to unopposed oestrogen
• PTEN, KRAS, PIK3CA mutations
• Can occur in association with Lynch syndrome (defective DNA mismatch repair gene)

Serous and clear cell carcinoma (type 2 tumours) - 20%

• Serous intraepithelial carcinoma is the precursor, not associated with unopposed oestrogen
• Affects elderly post-menopausal women
• TP53 mutation and overexpression
• Spreads along Fallopian tube mucosa and peritoneal surfaces so can present with extrauterine disease
• More aggressive than endometrioid/mucinous carcinoma

Spread

• Spread can be directly into the myometrium and cervix, through lymphatics, or haematogenous