Staying on hormone therapy when it is hard
Tamoxifen, aromatase inhibitors and androgen deprivation are taken for years, and a large minority stop early without telling anyone. What can be changed before stopping is the option.
5 min read · Part of Long-Term Effects
Written by The LifeAfterward editorial team from the sources listed at the end of this page.
Not individually reviewed by a clinician. This page is written from published clinical guidance, listed in full at the end, and is general information rather than medical advice — your own team knows your case. See our editorial standards.
Last checked against its sources · Last updated · Next check due
In short
- Hormone therapy is one of the most effective recurrence-reducing treatments there is, and its benefit depends on actually taking it.
- A large minority of people stop early or take it irregularly, and most do not tell their team — which removes the chance to fix the problem.
- Almost every common side effect has an approach: switching agent, changing timing, treating the symptom directly.
- Stopping should be a decision made with your oncologist, not one made alone at 3am after a bad week.
What this means
Taking a tablet every day for five to ten years, which makes you feel worse in order to reduce a risk you cannot see, is genuinely hard — and the difficulty is not a character flaw. What matters is that the alternatives are not "endure it" and "stop". There is a large middle ground that most people are never offered because they never say how bad it is.
What you are taking, and what it buys
- Tamoxifen
- Blocks oestrogen’s effect on breast cancer cells. Used before and after menopause, typically for five to ten years.
- Aromatase inhibitors
- Anastrozole, letrozole and exemestane lower oestrogen levels after menopause. The three are different drugs and are often tolerated differently.
- Ovarian suppression
- Injections that switch off the ovaries, used alongside other hormone therapy in some situations.
- Androgen deprivation therapy (ADT)
- Lowers testosterone in prostate cancer, by injection or tablet, sometimes for years.
Ask your oncologist for your own numbers: how much this reduces your risk of recurrence, over what period, and what is known about stopping early. A vague sense of "it helps" is much harder to hold on to at year four than a figure that applies to you.
What can be changed before you stop
- Joint and muscle pain
- The most common reason people stop an aromatase inhibitor. Switching to a different one often helps, because the three are not interchangeable in how they feel. Regular exercise has evidence here, and specific medications are sometimes used — ask.
- Hot flushes and night sweats
- Non-hormonal prescription options exist, and cognitive behavioural therapy has good evidence. Some antidepressants must be avoided with tamoxifen (see below), so this must be prescribed by someone who knows what you are on.
- Vaginal dryness and painful sex
- Moisturisers and lubricants first, and low-dose vaginal oestrogen is prescribed in some situations even on hormone therapy, in discussion with your oncologist. See sex and intimacy.
- Sleep and mood
- Both are treatable in their own right — see sleeping better and mental health after cancer.
- Timing
- Taking a tablet in the evening rather than the morning shifts where the worst of the effects land for some people. It is a free thing to try.
- Bone and heart
- Aromatase inhibitors and ADT both thin bone; ADT affects metabolic and cardiovascular risk. These need monitoring rather than tolerating — see heart and bone health.
- A planned break
- In some situations a supervised pause is a legitimate option, including for people hoping to conceive. That is a conversation to have, not a decision to take unilaterally.
Interactions worth knowing
- Some antidepressants strongly inhibit the enzyme that activates tamoxifen and are generally avoided with it. Always say you take tamoxifen before any antidepressant is prescribed, including by a family doctor.
- St John’s wort interferes with several cancer drugs, including hormone therapy — do not take it.
- Tell your pharmacist everything you take, including supplements. They will check the combination faster than anyone.
- Report new leg swelling or pain, breathlessness, or abnormal vaginal bleeding while on tamoxifen — see the advice section below.
Making five to ten years survivable
- Attach it to a fixed daily habit and use a phone alarm. Missing occasional doses is common; a system beats intention.
- Keep a note of side effects with dates rather than trying to summarise "it has been bad" in clinic — My Journey does this on your device.
- Book a specific appointment about tolerability rather than raising it in the last thirty seconds of a follow-up.
- Use the sentence that gets action: "I am finding this hard enough that I have thought about stopping. What are my options?"
- If you have already stopped, say so. Teams would far rather restart something than discover it three years later.
What to ask your healthcare team
- How much does this reduce my risk, and for how long do I take it?
- Could I try a different drug in the same class?
- What can be done about the joint pain, flushes, sleep or mood?
- Do I need bone density or cardiovascular monitoring while I am on this?
- Is a supervised break ever an option in my case?
- I have been missing doses — can we talk about that honestly?
Save questions to My Journey so you have them in the room, or use a ready-made list.
When to seek medical advice
Contact your healthcare team if you have:
- Side effects that have you considering stopping — this is the moment to say so, not after.
- Any vaginal bleeding after menopause while taking tamoxifen.
- New joint pain that is severe, or a fracture after a minor injury.
- Low mood or anxiety that started or worsened after beginning treatment.
Get emergency help the same day if you have:
- Calf pain and swelling, sudden breathlessness or chest pain — possible clot, which is a recognised risk with tamoxifen.
- Sudden vision changes, severe headache, or one-sided weakness.
If you are worried and unsure, contact your team anyway — they would far rather hear from you unnecessarily than late. What to do in an emergency.
Common questions
What happens if I stop hormone therapy early?
Stopping early reduces the protection the treatment gives against recurrence, and how much depends on your situation — ask your oncologist for your own figures. The important point is that stopping is not the only alternative to enduring it: switching drug, changing timing and treating the specific side effect all keep more people on treatment.
Can I switch aromatase inhibitors if the joint pain is bad?
Often yes. Anastrozole, letrozole and exemestane are different drugs and people frequently tolerate one considerably better than another, so a switch is a standard response to joint pain rather than a last resort. Exercise also has evidence for this specific side effect.
Sources
This page was written from the guidance below and checked against it on . Links are re-checked at each review — see our editorial standards.
- ASCO (Cancer.Net). Survivorship
- American Society of Clinical Oncology. Survivorship clinical practice guidelines
- National Comprehensive Cancer Network. NCCN Guidelines for Patients
- National Cancer Institute (US). Late effects of cancer treatment
- Macmillan Cancer Support. After treatment finishes