Menopause after breast cancer, or when your breast cancer risk is high

You've finished your treatment, you're on tamoxifen or letrozole, and you haven't slept properly in months. Or somebody told you to stop your HRT in the same week they told you that you had DCIS. Or your mother had breast cancer, and you've been told HRT isn't for you — and nobody has said why.

This could possibly also be you.

Having had breast cancer, or being at high risk of it, doesn't mean nothing can be done about your menopause. There are treatments without hormones that work for hot flushes, sleep and vaginal symptoms. For some women, hormone therapy is still part of the conversation — that depends on your own pathology report, your own risk, and how much your symptoms are affecting your life. I'm a breast specialist and a menopause specialist, so we can look at both sides of that together.

Who this appointment is for

You've had breast cancer or DCIS, whether treatment finished last month or ten years ago.
You're on tamoxifen, an aromatase inhibitor (letrozole, anastrozole or exemestane) or ovarian suppression, and struggling with flushes, sleep, mood, joint aches or vaginal dryness.
Your menopause came early because of chemotherapy, ovarian suppression or surgery to remove your ovaries.
You've been diagnosed with breast cancer or DCIS while on HRT and you're not sure whether to stop.
You carry a BRCA gene change or have a strong family history, including after risk-reducing surgery.
You've been told your breast cancer risk is high and you want to know what that means for HRT.

Why a breast specialist who is also a menopause specialist

Most women in this position see one doctor for the breast and another for the hormones. The question of what you can take for your menopause sits between the two, and it often falls down the gap. I do the operations, I explain the pathology reports, and I look after the menopause afterwards.

I work alongside your oncology team, not instead of it. If you'd like, I'll send a letter to your oncologist or GP after your appointment, and you always get a copy of the letter yourself.

Treatments without hormones

For hot flushes and night sweats there are several options that don't involve oestrogen.

Venlafaxine, often at a low dose. It usually works within one to two weeks.
Gabapentin at night, if night sweats are the main problem.
Oxybutynin, which works well but can give you a dry mouth.
Newer tablets that act on the brain's temperature centre: fezolinetant (Veoza) and elinzanetant (Lynkuet). Elinzanetant has been tested in women on tamoxifen and aromatase inhibitors. Neither is approved in New Zealand yet.
Cognitive behavioural therapy (CBT), which has the best evidence of the non-drug options.
A cooler bedroom, layers, and avoiding alcohol.

If you're on tamoxifen, paroxetine and fluoxetine need to be avoided, because they block the enzyme in the liver (CYP2D6) that switches tamoxifen on.

Flushes are one of the commonest reasons women quietly stop their endocrine therapy. Treating them protects the treatment. Please don't stop your tamoxifen or aromatase inhibitor on your own — talk to your team, or to me.

Vaginal dryness, pain with sex and bladder symptoms

Vaginal moisturisers used regularly, not only lubricant on the day, help many women and are under-used.

Vaginal oestrogen is a separate question from HRT. It's a much smaller dose, put where the problem is, and in my practice it is always an option after breast cancer, whichever endocrine therapy you're on. A 2025 review of more than 38,000 women on endocrine therapy found no increase in deaths with vaginal oestrogen, and no increase in recurrence on tamoxifen. For women on an aromatase inhibitor it couldn't completely rule out a small increase in recurrence, though the certainty of that finding was graded low, and we can talk it through.

Hormone therapy (HRT or MHT)

For some women after breast cancer, hormone therapy is still worth discussing. For others it isn't. What decides it:

Whether it was DCIS or invasive cancer. DCIS that has been fully removed is a different situation from invasive cancer, although women are often given the same answer for both.
Your receptor status — ER, PR and HER2, on your pathology report.
Your own risk of the cancer coming back, as a number. Your oncology team can calculate this.
How much your symptoms are affecting your life.

What the evidence shows. Pooled across four randomised trials of about 4,000 women, HRT after breast cancer was linked to more recurrences (hazard ratio 1.46). In hormone-receptor-positive cancers the increase was larger (1.8). In hormone-receptor-negative cancers it was smaller (1.19) and not statistically significant.

What these numbers don't tell you. The trials were small and old, several were stopped early, and some used preparations we no longer use. And a percentage increase means nothing until you know your own starting risk: about 46% more on a risk of 5 in 100 is a very different thing from 46% more on a risk of 25 in 100.

After treated DCIS, if your symptoms are badly affecting your life, I lean towards supporting HRT rather than refusing it automatically. Not every specialist holds this view, and that's worth knowing. If HRT is right for you, I usually prefer oestrogen through the skin, as a patch or gel, with micronised progesterone (Utrogestan). Tibolone isn't used after breast cancer.

If you're diagnosed while on HRT

Please don't stop your HRT in a panic at the biopsy. Stopping suddenly brings a wall of menopause symptoms within two to three weeks, and it changes nothing about the DCIS. A core biopsy is a keyhole, not the whole room — the final pathology after surgery tells us whether it's pure DCIS or whether there's an invasive part.

In my practice, pure DCIS is not on its own a reason to stop your HRT. If it turns out to be invasive, the conversation changes. It becomes an individual decision with your breast team and your oncologist, with the facts in front of everyone.

If your risk is high but you haven't had breast cancer

A family history doesn't automatically rule out HRT. We look at your own risk — your family history, your breast density, any gene test results — and decide together, with good follow-up imaging.

If you carry a BRCA gene change and have had your ovaries removed to lower your risk, the studies so far are mostly reassuring. A 2018 meta-analysis of 1,100 women found no increase in breast cancer with HRT after the surgery (hazard ratio 0.98). A 2026 study of 919 women found no increase with oestrogen-only HRT or with combined HRT.

Bones and heart

If treatment brought your menopause on early, you have more years without oestrogen ahead of you, and that matters for your bones and your heart. Where HRT is an option, it protects both. Tamoxifen helps too: after menopause it protects bone density, and it lowers cholesterol. Aromatase inhibitors work differently and can thin bones, so your bones need checking if you're on one.

What to bring

Your pathology report or the letter from your surgeon: whether it was DCIS or invasive, the size, the grade, whether lymph nodes were involved, and your ER, PR and HER2 status.
A list of everything you take, including your endocrine therapy and how long you've been on it.
Your three worst symptoms, and how many nights a week they wake you.

How to book

Fill in the request form or phone Linda on 027 277 6239. Appointments are in person at Boulcott Specialist Centre in Lower Hutt, Wellington, or by phone or video call. You don't need a GP referral, though some health insurers ask for one. Fees are on the prices page.

Watch

When not to wait

Pain or swelling in one calf, or sudden breathlessness or chest pain: go to the emergency department now. Tamoxifen and HRT both raise the risk of clots.
Any vaginal bleeding after your menopause, especially on tamoxifen: phone your doctor the same day.
A new lump, or a change in the skin of either breast or in a scar: see your doctor within a day or two.

This page is general information, not personal medical advice. Talk to your own doctor about what's right for you.

Sources

Poggio F et al. Safety of systemic hormone replacement therapy in breast cancer survivors: a systematic review and meta-analysis. Breast Cancer Res Treat 2021. DOI
Kastora SL et al. Safety of topical estrogen therapy during adjuvant endocrine treatment among patients with breast cancer. Cancer Treat Rev 2025. DOI
Marchetti C et al. Hormone replacement therapy after prophylactic risk-reducing salpingo-oophorectomy and breast cancer risk in BRCA1 and BRCA2 mutation carriers: a meta-analysis. Crit Rev Oncol Hematol 2018. DOI
Regev-Sadeh S et al. Hormone therapy after oophorectomy and breast cancer risk in women with BRCA pathogenic variant. JAMA Netw Open 2026. DOI
Pogoda K et al. Neurokinin pathway antagonists for vasomotor symptoms in women with breast cancer: focus on elinzanetant and fezolinetant. Breast 2026. DOI