# Menopause brought on by cancer treatment, and the options for it

Source: https://onco.cc/technologies/menopause-after-cancer-treatment/  
OnCo record `menopause-after-cancer-treatment` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Treatment can bring on menopause in a week rather than a decade, and the usual answer, hormone replacement, is often unavailable. The non-hormonal options now have real trial evidence: elinzanetant cut moderate to severe hot flushes by three and a half episodes a day more than placebo in women on endocrine therapy, and venlafaxine and oxybutynin also beat placebo.

## Summary

Chemotherapy-induced ovarian failure, ovarian suppression, removal of the ovaries and aromatase inhibitors all produce menopausal symptoms, and the abruptness makes them worse than a natural menopause. Hot flushes are the symptom that drives women to stop endocrine therapy early, which is why treating them is not cosmetic.

Neurokinin-targeted drugs are the change. In a phase 3 trial of 474 women taking endocrine therapy for hormone-receptor-positive breast cancer or its prevention, elinzanetant 120 mg daily reduced the mean daily frequency of moderate to severe vasomotor symptoms from a baseline of about 11.4 episodes by 6.5 at week 4 against 3.0 on placebo, a difference of 3.5 episodes (95 per cent confidence interval 4.4 to 2.6), and by 7.8 against 4.2 at week 12. Headache, fatigue and somnolence were the commonest adverse events.

The older options still work. Venlafaxine, in 191 evaluable women with a history of breast cancer or a wish to avoid hormones, reduced median hot flush scores at four weeks by 61 per cent at 75 mg and 150 mg against 27 per cent on placebo. Oxybutynin, in 150 women of whom 65 per cent were taking tamoxifen or an aromatase inhibitor, reduced weekly hot flush score by 16.9 points at 5 mg twice daily and 10.6 at 2.5 mg twice daily against 5.7 on placebo. Behavioural approaches, including cognitive behavioural therapy, paced breathing and hypnosis, are recommended for both sexes by ASCO.

One interaction matters enough to say on its own. Paroxetine and fluoxetine inhibit CYP2D6, the enzyme that converts tamoxifen into its active metabolite. A population-based cohort of women taking tamoxifen found increased breast cancer mortality with overlapping paroxetine use. Venlafaxine is a weak inhibitor and is the usual choice for a woman on tamoxifen. This is a question for the prescriber, not a reason for anyone to stop a tablet on their own.

Bone loss, vaginal dryness and sexual difficulty travel with treatment-induced menopause and have their own records here.

What comes back, and when: it depends on whether the ovaries recover, which is covered in the record alongside this one. Where menopause is permanent, the symptoms themselves usually ease over several years, as they do after a natural menopause, and in the meantime the treatments above have randomised evidence behind them. Vaginal dryness is the exception: it does not improve with time and tends to worsen.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-10-02
- Tags: rejuvenation; survivorship; evidence:strong
- Principle: Oestrogen withdrawal narrows the thermoneutral zone in the hypothalamus, so small changes in core temperature trigger flushing and sweating. Neurokinin-3 receptor antagonists act on the hypothalamic KNDy neurons that drive that signal, which is why they work without oestrogen. Serotonin-noradrenaline reuptake inhibitors and anticholinergics act less directly and with smaller effects.
- Strengths: A large randomised trial of elinzanetant specifically in women on endocrine therapy for breast cancer; Venlafaxine and oxybutynin are cheap, generic and placebo-controlled; Treating flushes may keep women on the endocrine therapy that prevents recurrence
- Limitations: None of these restore oestrogen, and none help vaginal dryness; Paroxetine and fluoxetine interact with tamoxifen; Access and cost of the newer agents vary by country

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Menopause
- OASIS-4: elinzanetant for vasomotor symptoms from endocrine therapy for breast cancer (NEJM 2025): https://doi.org/10.1056/NEJMoa2415566
- Venlafaxine in management of hot flashes in survivors of breast cancer: randomised controlled trial (Lancet 2000): https://doi.org/10.1016/S0140-6736(00)03403-6
- Oxybutynin versus placebo for hot flashes in women with or without breast cancer (ACCRU SC-1603) (JNCI Cancer Spectr 2020): https://doi.org/10.1093/jncics/pkz088
- Selective serotonin reuptake inhibitors and breast cancer mortality in women receiving tamoxifen (BMJ 2010): https://doi.org/10.1136/bmj.c693
- Interventions to Address Sexual Problems in People With Cancer: ASCO guideline adaptation (JCO 2018): https://doi.org/10.1200/JCO.2017.75.8995

## Connected records

- cancers: [Cervical cancer](https://onco.cc/cancers/cervical/), [Endometrial cancer](https://onco.cc/cancers/endometrial/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- fronts: [Hormonal Therapy](https://onco.cc/fronts/hormonal/), [Recovery & Rejuvenation](https://onco.cc/fronts/rejuvenation/), [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- technologies: [Bone loss caused by cancer treatment, and what rebuilds it](https://onco.cc/technologies/cancer-treatment-bone-loss/), [Cognitive behavioural therapy for fatigue and distress](https://onco.cc/technologies/cbt-fatigue-distress/), [Endocrine therapy (SERMs, AIs, SERDs)](https://onco.cc/technologies/endocrine-therapy/), [Fertility in girls and young women treated for cancer, including ovarian tissue freezing](https://onco.cc/technologies/rejuv-paed-fertility-female/), [Fertility, growth and what total body irradiation costs](https://onco.cc/technologies/rejuv-tx-fertility-and-growth/), [Hormones, metabolism and the heart after transplant](https://onco.cc/technologies/rejuv-tx-endocrine-and-cardiometabolic/), [Mindfulness-based stress reduction and cognitive therapy](https://onco.cc/technologies/mindfulness-based-interventions/), [Ovarian function after chemotherapy: who recovers, and when](https://onco.cc/technologies/ovarian-function-after-chemotherapy/), [Sexual function and intimacy after cancer, for both sexes](https://onco.cc/technologies/sexual-function-after-cancer/), [Sleep after cancer: how common insomnia is, how long it lasts, and the treatment that works](https://onco.cc/technologies/rejuv-mind-sleep-after-cancer/), [The pituitary, puberty and the hypothalamic axis after cranial radiotherapy in childhood](https://onco.cc/technologies/rejuv-paed-pituitary-and-puberty/), [Vaginal oestrogen after breast cancer: what the evidence says, and where it disagrees](https://onco.cc/technologies/vaginal-oestrogen-after-breast-cancer/)
- drugs: [Anastrozole](https://onco.cc/drugs/anastrozole/), [Exemestane](https://onco.cc/drugs/exemestane/), [Goserelin / leuprolide (ovarian function suppression)](https://onco.cc/drugs/goserelin/), [Letrozole (and other aromatase inhibitors)](https://onco.cc/drugs/letrozole/), [Tamoxifen](https://onco.cc/drugs/tamoxifen/)
- terms: [Aromatase inhibitor](https://onco.cc/terms/aromatase-inhibitor/), [Late effects and survivorship toxicity](https://onco.cc/terms/late-effects/), [Menopause symptoms after chemotherapy for breast cancer](https://onco.cc/terms/menopause-after-chemotherapy-breast/), [Ovarian function suppression (OFS)](https://onco.cc/terms/ovarian-function-suppression/)
- trials: [A Study to Learn More About How Well Elinzanetant Works and How Safe it is Compared to Placebo for the Treatment of Hot Flashes Caused by Anti-cancer Therapy in Women With, or at High Risk for Developing Hormone-receptor Positive Breast Cancer](https://onco.cc/trials/nct05587296/)
- bottlenecks: [Survivorship and late effects are neglected](https://onco.cc/bottlenecks/b-survivorship/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/)
- key papers: [Elinzanetant for Vasomotor Symptoms from Endocrine Therapy for Breast Cancer](https://onco.cc/key-papers/paper-nct05587296-n-engl-j-med-2025/)

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