Why Do My Joints Hurt on Hormone Therapy? A Physio Explains

If you are living with or recovering from breast cancer and taking hormone therapy medication, you may have noticed an unexpected side effect: your joints hurt. You might wake with stiff hands in the morning, or feel aching in your hips, knees, or wrists in a way you never have before. It’s easy to put this down to getting older, or assume it’s simply something you have to live with.

You are not alone – and it is not just ageing.

What you may be experiencing is a condition called Aromatase Inhibitor Musculoskeletal Syndrome (AIMSS). It affects up to half of all women taking aromatase inhibitor medications such as anastrozole, letrozole and exemestane and it is one of the most common reasons women consider stopping their medication early.

What are Aromatase Inhibitors & how do they Impact Joints & Tendons? 

Aromatase inhibitors (AI’s) are a type of hormone therapy commonly prescribed for oestrogen receptor-positive breast cancer, usually after surgery or chemotherapy. They work by blocking the production of oestrogen in the body, which helps prevent cancer from returning. For many women, they are a crucial part of long-term cancer management. 

But oestrogen does many things within the body. It plays an important role in keeping your joints, tendons and muscles healthy. When AI medication reduces oestrogen levels, some women experience a range of musculoskeletal symptoms – including joint pain, muscle aches, tendon problems, morning stiffness, reduced grip strength and even carpal tunnel syndrome. These symptoms usually begin within the first few months of starting AI therapy, though they can appear at any time during treatment.

What Does AIMSS Feel Like?

AIMSS can feel different for different people. Common symptoms include:

• Stiffness and aching in the hands, fingers, wrists, hips, knees or ankles – often on both sides of the body (but not always)
• Morning stiffness that takes more than 30 minutes to ease
• Tendon pain or swelling, particularly in the wrists, feet, or knees
• Reduced grip strength 
• Tingling or numbness in the hands at night
• A general feeling that your body is stiff or “seizing up”

Some women describe feeling like they have suddenly aged overnight. Others find that activities they used to do easily – gardening, playing sport, cooking or even opening a jar – have become genuinely painful.

Why It Matters Beyond the Pain

AIMSS is one of the leading reasons women stop taking their AI medication early, with studies suggesting up to 50% of women may discontinue treatment due to these side effects.

This matters enormously – because stopping your AI medication early can reduce its effectiveness in preventing cancer from returning. If your joint pain is making you consider stopping your medication, please speak with your oncologist or GP before making any changes. There are options available, including switching to a different AI or trialling a medication break under medical supervision, that may help ease symptoms. 

You do not have to simply push through the pain – but you also do not have to manage it alone.

How Can Physiotherapy Help?

The good news is that there is strong evidence that physiotherapy can make a real difference for women with AIMSS.

Physio Led Exercise at Inner Strength Bayside

Exercise therapy is the most well-researched treatment, with studies consistently showing that a combination of aerobic exercise (such as walking, swimming, or cycling) and resistance training (strengthening exercises, such as our Physio Led Group sessions) – significantly reduces joint pain and stiffness, improves physical function and importantly helps women stay on their AI medication for longer.

Research recommends aiming for around 150 minutes of moderate aerobic activity per week, combined with two resistance training sessions per week. Yoga and tai chi have also shown benefits for joint pain and quality of life.

A physiotherapist can also assess and treat specific problems such as tendinopathy, adhesive capsulitis (frozen shoulder), or carpal tunnel syndrome – all of which are more common in women taking AIs.

Beyond exercise, physiotherapy can help you understand why you are in pain, develop strategies to manage it day to day and work with your broader healthcare team to make sure your cancer treatment stays on track.

What Should You Do Next?

If you are taking an aromatase inhibitor and experiencing joint or muscle pain, do not dismiss it. Mention it to your oncologist, GP, or physiotherapist. Ask specifically about AIMSS.

At Inner Strength Bayside, our physiotherapists have experience working with women managing the side effects of breast cancer treatment. We take a whole-person approach – looking beyond the painful joint to understand how your cancer treatment, lifestyle, and overall health are all connected.

You have worked hard to get through cancer treatment. Let us help you feel like yourself again. Call 8555 4099 to book an appointment or follow the prompts to book with us online. 

References

Thiébaut, A., et al. (2024). Aromatase inhibitor–associated musculoskeletal syndrome: Clinical features and management. PM&R. Advance online publication.

Lombard, J. M., et al. (2024). Management of aromatase inhibitor–induced musculoskeletal symptoms: A critical review. Critical Reviews in Oncology/Hematology. Advance online publication.

Yennu, S., et al. (2023). Management of aromatase inhibitor–associated musculoskeletal symptoms: ASCO guideline. Journal of Clinical Oncology.

Felson, D. T., & Cummings, S. R. (2005). Aromatase inhibitor–associated musculoskeletal symptoms: Diagnostic considerations and clinical framework.

Irwin, M. L., et al. (2015). Randomized controlled trial of exercise for aromatase inhibitor–induced arthralgia (HOPE study). Journal of Clinical Oncology, 33(10), 1104–1111. https://doi.org/10.1200/JCO.2014.58.6608