Author: Molly Lindquist
Medically reviewed by Dr. Doug Blayney on September 12, 2024.
Aromatase inhibitors are a type of drug that some breast cancer patients take either after to help prevent breast cancer from coming back, or to stop the growth of breast cancer metastases. These medicines help fight cancer by lowering the amount of estrogen in the body. Estrogen can make some breast cancers grow, so reducing it can slow down or stop cancer growth. While these medicines are important for treating cancer, they can have side effects. One worry is that they might cause bone loss, which can make bones weaker and more likely to break.
Today, we're going to explore whether all aromatase inhibitors cause bone loss and how we can manage this side effect.
What Are Aromatase Inhibitors?
Aromatase inhibitors are medicines that help lower the amount of estrogen in the body. They do this by blocking an enzyme called aromatase, which the body needs to make estrogen. By reducing estrogen, these medicines can slow down or stop the growth of some types of breast cancer. Estrogen is made in the ovaries, the fat cells, and the breast tissue. After menopause, the ovaries no longer make estrogen. Because the Aromotase Inibitors are not strong enough to overcome the ovaries’ manufacture of estrogen, another method of halting estrogen production – ovarian suppression – is used in pre menopausal women to stop estrogen production.
There are different aromatase inhibitors, used in the US:
- Anastrozole
- Letrozole
- Exemestane
Each of these medicines works in a similar way to block the aromatase enzyme and reduce estrogen levels. They're important tools in fighting breast cancer, but like all medicines, they can have side effects. One of the main concerns is that they might cause bone loss.
Read more about side effects of AIs here:
How Do Aromatase Inhibitors Affect Bones?
To understand how aromatase inhibitors might affect bones, we first need to know a bit about how bones stay healthy. Bones are living tissue that's always changing. Our bodies are constantly breaking down old bone and building new bone to replace it.
Estrogen plays a big role in keeping bones strong. It helps balance the process of breaking down old bone and building new bone. When estrogen levels drop, the body might break down bone faster than it can build new bone. This can lead to bone loss over time.
Since aromatase inhibitors work by lowering estrogen levels, they can upset this balance. This is why doctors are concerned about bone health in people taking these medicines.
Do All Aromatase Inhibitors Cause Bone Loss?
Now, let's address the big question: do all aromatase inhibitors cause bone loss? The short answer is that all of them can potentially cause some degree of bone loss, but the amount can vary.
Studies have shown that most people taking aromatase inhibitors often experience some bone loss. However, the amount of bone loss can be different for each person. It can depend on things like:
- Which specific aromatase inhibitor you're taking
- How long you've been taking the medicine
- Your overall health
- Your diet and lifestyle, including the amount of upright exercise you get each day
- Other medicines you might be taking
Some studies have found that different aromatase inhibitors might affect bones slightly differently. For example, some research suggests that exemestane might have a bit less impact on bones compared to anastrozole or letrozole. However, all of them can potentially cause some bone loss.
It's important to remember that while bone loss is a concern, these medicines are still very important for treating breast cancer. The benefits of taking them often outweigh the risks for many people.
How Can We Prevent Bone Loss While Taking Aromatase Inhibitors?
If you're taking an aromatase inhibitor, there are several things you can do to help keep your bones healthy:
- Get enough calcium and vitamin D: These nutrients are important for bone health. You can get them from foods like dairy products, leafy green vegetables, and fatty fish. Your doctor might also recommend supplements.
- Exercise regularly: Weight-bearing exercises like walking, jogging, or dancing can help keep bones strong. Resistance exercises with weights or bands can also be helpful.
- Don't smoke: Smoking can make bone loss worse, so it's best to avoid it.
- Limit alcohol: Drinking too much alcohol can also harm your bones.
- Have regular bone density tests: Your doctor might recommend regular tests to check your bone health. This can help catch any problems early.
- Consider other medicines: In some cases, your doctor might prescribe medicines to help protect your bones. These could include drugs called bisphosphonates or some monoclonal antibodies, which help slow down bone loss.
What About Long-Term Bone Health?
Taking aromatase inhibitors for a long time can affect your bones, but it doesn't mean you'll definitely have serious problems. Many people take these medicines for years without major issues. However, it's important to keep an eye on your bone health.
Some people might experience joint pain while taking aromatase inhibitors. This can be uncomfortable and might make you want to stop taking the medicine. If you're having side effects like this, it's important to talk to your doctor. They might be able to suggest ways to manage the pain or consider other treatment options.
New Research and Future Treatments
Scientists are always working on new ways to treat breast cancer and manage side effects. Some recent research has looked at:
- New types of medicines that might have less impact on bones
- Ways to use existing medicines more effectively
- Treatments that could help protect bones while still fighting cancer
While we don't have all the answers yet, this research gives us hope for even better treatments in the future.
Stories from People Like You
Many people have shared their experiences with taking aromatase inhibitors. Here are a few things we've heard:
"I was worried about bone loss when I started taking anastrozole, but my doctor helped me come up with a plan. I started taking calcium supplements and doing more weight-bearing exercises. My latest bone scan showed that my bones are staying strong!" - Sarah, 62
"The joint pain was tough at first, but working with a physical therapist really helped. Now I can manage the pain and keep taking my medicine." - Maria, 58
"I switched from one aromatase inhibitor to another because of side effects. It took some time to find the right one for me, but now I'm doing well. Don't be afraid to speak up if you're having problems!" - Lisa, 55
These stories show that while taking aromatase inhibitors can be challenging, many people find ways to manage the side effects and stay healthy.
Where to Find Support
The Manta Cares team is composed of cancer survivors, caregivers and oncologists - so we truly understand the challenges that come with a cancer diagnosis because we’ve been there. We are here to walk with you as you go through your own cancer experience. Please don’t hesitate to reach out with any questions. We are even developing disease-specific step-by-step maps to show you all the paths you might face during your cancer experience and connect you with relevant support and resources. Sign up for access to our Manta Maps here.
Be sure to subscribe to our newsletter and check out our free resources like our Chemotherapy Checklist for Caregivers, Financial Checklist for Cancer Treatment and more. We also put out a bi-weekly podcast called the Patient from Hell to educate, empower and hopefully inspire you as you go through this crappy experience. You can listen on Spotify, Apple Podcasts, YouTube or anywhere you listen to podcasts. Dealing with cancer as a patient or caregiver can feel really lonely. Just know that you are not alone in this experience.
Wrapping Up
Aromatase inhibitors are important medicines for treating some types of breast cancer. While they can cause bone loss, there are ways to manage this side effect and keep your bones healthy. All aromatase inhibitors can potentially affect bone health, but the impact can vary from person to person.
The key things to remember are:
- Work closely with your healthcare team to monitor your bone health.
- Take steps to keep your bones strong through diet, exercise, and other healthy habits.
- Don't hesitate to speak up if you're having side effects or concerns.
- Remember that there are resources and support available to help you through your treatment journey.
By staying informed and proactive, you can take care of your overall health while fighting cancer. Always talk to your doctor about any questions or concerns you have about your treatment.
Also Read:
- Tips for Finding Balance After Early Stage Breast Cancer
- Life After Early Stage Breast Cancer: Your Survivorship Care Plan
- Why Diet and Nutrition Are Important for Cancer Patients
FAQs: Do All Aromatase Inhibitors Cause Bone Loss
Q: Do all aromatase inhibitors cause osteoporosis?
Ans - All aromatase inhibitors can lead to bone loss and increase the risk of osteoporosis because they lower estrogen levels, which help keep bones strong. Osteoporosis develops after osteopenia or low bone density. Bone density tests can help detect both osteoporosis and its precursor, osteopenia, to help decide when treatment to prevent bone loss might be helpful.
Q: How to prevent bone loss while taking anastrozole?
Ans - To prevent bone loss, take calcium and vitamin D supplements, exercise regularly against gravity (that is walking, jogging, running and resistance training), avoid smoking and alcohol, and talk to your doctor about medicines that can help protect your bones.
Q: What percent of patients discontinue aromatase inhibitors due to adverse effects?
Ans - Around 20-30% of patients stop taking aromatase inhibitors because of side effects like joint pain, bone loss, or other discomforts. Many people find that switching to another aromatase inhibitor will reduce or eliminate their symptoms, and allow them to continue to benefit from the anti cancer effects of aromatase inhibitors.
Q: Do all aromatase inhibitors cause joint pain?
Ans - Many people taking aromatase inhibitors experience joint pain, but not everyone will have this side effect. The joint pain can go away after several months on its own.
Q: What are aromatase inhibitors, and why are they used in breast cancer treatment?
Ans - Aromatase inhibitors (AIs) are medications used to lower estrogen levels in the body by blocking the enzyme aromatase, which converts androgens into estrogen. They are commonly prescribed for postmenopausal women with hormone receptor-positive breast cancer to reduce the risk of cancer recurrence.
Q: How do aromatase inhibitors cause bone loss?
Ans - AIs reduce estrogen levels in the body, and estrogen plays a crucial role in maintaining bone density. Lower estrogen levels can accelerate bone resorption (the process by which bone is broken down), leading to decreased bone density and an increased risk of osteoporosis and fractures.
Q: Which aromatase inhibitors are most likely to cause bone loss?
Ans - All three main aromatase inhibitors—anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin)—can cause bone loss. However, the extent of bone loss can vary among individuals, and some studies suggest slight differences in bone loss rates between the different AIs.
Q: What are the signs and symptoms of bone loss or osteoporosis in patients taking aromatase inhibitors?
Ans - Early-stage bone loss may not have obvious symptoms. However, over time, patients may experience bone pain, fractures (particularly in the spine, hip, or wrist), loss of height, or a stooped posture. Routine bone density scans can help detect bone loss before symptoms appear.
Q: How is bone health monitored in breast cancer patients taking aromatase inhibitors?
Ans - Bone health is typically monitored through regular bone mineral density (BMD) tests, such as dual-energy X-ray absorptiometry (DEXA) scans. Healthcare providers may recommend these tests at baseline (before starting AI therapy) and periodically thereafter to assess bone loss and guide treatment decisions.
Q: What steps can breast cancer patients take to prevent or minimize bone loss while on aromatase inhibitors?
Ans - Patients can take several steps to protect bone health, including:
- Taking calcium and vitamin D supplements as recommended by their healthcare provider.
- Engaging in weight-bearing exercises like walking, jogging, or resistance training.
- Avoiding smoking and excessive alcohol consumption.
- Considering medications, such as bisphosphonates or denosumab, that help strengthen bones.
Q: Are there any alternative treatments for hormone receptor-positive breast cancer that do not cause bone loss?
Ans - Tamoxifen, another type of hormone therapy, may not cause as much bone loss in postmenopausal women and might even help maintain bone density. However, it has other side effects and risks. The choice between tamoxifen and aromatase inhibitors depends on various factors, including the patient’s menopausal status, risk of recurrence, and personal health profile.
Q: Can bone loss from aromatase inhibitors be reversed after stopping treatment?
Ans - Some degree of bone density recovery may occur after stopping AI therapy, but it is often incomplete, especially if significant bone loss has occurred. Ongoing management and preventive strategies may still be needed after discontinuing AIs.
Q: Who is at the highest risk for bone loss while taking aromatase inhibitors?
Ans - Factors that increase the risk of bone loss in AI users include older age, a history of fractures, low baseline bone density, a family history of osteoporosis, early menopause, low body weight, smoking, and lack of physical activity.
Q: Should I discuss bone loss concerns with my oncologist before starting aromatase inhibitors?
Ans - Yes, it is important to discuss potential side effects, including bone loss, with your oncologist before starting AI therapy. Your healthcare provider can assess your individual risk, recommend preventive strategies, and monitor your bone health throughout treatment.
Disclaimer: All content and information provided in connection with Manta Cares is solely intended for informational and educational purposes only. This content and information is not intended to be a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.