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Endometriosis - Management
Basis for recommendation

Seek specialist advice

  • CKS recommends seeking specialist advice as it is not clear what type of hormone replacement therapy (HRT) is best for women who have endometriosis, whether or not they have had a total hysterectomy or oophorectomy. The decision should be made on an individual basis taking the following into account:
    • The woman's family history.
    • Unopposed oestrogen may reactivate any residual disease and combined HRT may protect against this [RCOG, 2006].
    • Adenocarcinomas arising from pelvic endometriosis have been reported in women treated with unopposed oestrogen [Van Gorp and Neven, 2002]. Limited evidence suggests that combined HRT is associated with a lower risk of malignant change than treatment with unopposed oestrogens [Oxholm et al, 2007]. 
    • The risk of breast cancer appears to be increased by all HRT regimens (unopposed oestrogen, combined HRT, and tibolone) but seems to be greatest with combined HRT [Rees and Purdie, 2006].
    • Tibolone may slightly increase the risk of endometrial cancer [Rees and Purdie, 2006].
    • CKS expert reviewers stressed the importance of explaining the risks and benefits to the woman.

Women who have had bilateral oophorectomy

  • The Royal College of Obstetricians and Gynaecologists recommend HRT in young women who have had a bilateral oophorectomy, because of the overall health benefits and the small risk of recurrence of endometriosis whilst taking HRT [RCOG, 2006].
  • A Cochrane systematic review concluded that although there is a risk that HRT might cause recurrence of endometriosis in women who have had a bilateral oophorectomy for severe endometriosis, the available evidence (from two small randomized controlled trials) is not strong enough to deprive severely symptomatic women of treatment.
  • There is no good evidence on whether to recommend an unopposed HRT regimen, a combined-continuous regimen, or tibolone [Rees and Purdie, 2006].
  • Prescribing combined HRT after hysterectomy may protect against the unopposed action of the oestrogen on any residual disease [RCOG, 2006]. However the small risk of avoiding reactivation of the endometriosis or malignant transformation should be balanced against the increased risk of breast cancer reported with combined HRT regimens and with tibolone [RCOG, 2006].

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