Breast Cancer and Osteoporosis Risk

If you’re visiting this site, you probably already know what breast cancer is.  And if you’ve glanced over our blog lately, you know that in several recent articles we’ve been educating our readers about osteoporosis.  Once you read this article, you’ll know how breast cancer and osteoporosis risk are linked, and what to do about it.

Many Breast Cancer Treatments Contribute to Osteoporosis

As we’ve mentioned, many cancers are affected by sex-hormone levels.  Breast cancers, typically, are “estrogen-receptor-positive tumors,” which means their growth can be sped or reduced by increasing or decreasing levels of estrogen in the body.  Therefore, many modern cancer-treatments work to suppress estrogen or the glands (ovaries) or biochemical pathways that produce it.

That’s not all good news.  Cancer Therapy Advisor describes a 2018 study this way: 

“The researchers found that survivors of breast cancer had a 68% higher risk of osteopenia and osteoporosis compared with cancer-free women.”

Many studies have been done on this topic.  Here are a few extracts:

  • 2006 – “Monitoring and management of bone loss associated with AI [aromatase inhibitor] treatment are essential and are being addressed in ongoing trials.” (PubMed)
  • 2015 – in women receiving AI treatments and tamoxifen, 26% had osteopenia and 9.5% had osteoporosis. (PubMed)
  • 2018 – “Small but consistent declines in total hip and lumbar spine BMD [bone mass density] were present in breast cancer patients following AI therapy.”  Decline was around 1% per year, and higher in younger women than in older. (PubMed)
  • 2019 – “Of 1692 breast cancer survivors, 312 [18%] developed osteoporosis during a median follow-up of 5 years. … The natural, age-related reduction in bone density is exacerbated by breast cancer active AI treatment.” (PubMed)

So, it is well documented that certain hormonal treatments for breast cancer significantly increase risk of bone-mass problems within the next few years.  Radiotherapy has also been shown to decrease bone density near the radiation site.  If you are undergoing these types of treatments, your oncologist has probably already discussed this risk with you.

Since you also understand how high estrogen can be a risk factor for cancer recurrence, it should be clear that boosting estrogen in the hopes of increasing your bone mass density (BMD), once you’re in remission, is not a good solution.  In fact, increasing BMD “by any possible means” is unwise.  As one final study points out, “Elderly women with high BMD have an increased risk of breast cancer, especially advanced cancer, compared with women with low BMD.” (PubMed)

What about Osteopenia?

At the start of this article we mentioned osteopenia.  “Osteopenia” is a medical term for “low bone mass”—compared against an average.  Whether it is a problem for you depends on what is normal and healthy for your body.  Many slender (thinly built) people have always had “low” bone mass (compared to the average) and are perfectly strong and healthy.  So, osteopenia is:

  • not necessarily an indicator of your bone health
  • not necessarily a precursor to osteoporosis
  • not considered a disease

In other words: unless you are a large-boned person who has recently lost a lot of bone mass (but doesn’t yet have an “osteoporosis” diagnosis), don’t spend any energy worrying about “osteopenia,” but just continue to get your BMD checked if you are at risk of developing osteoporosis.

Detecting Osteoporosis

The current medical standard for detecting/diagnosing osteoporosis (and osteopenia) is an X-ray scan known as “Dual Energy X-ray Absorpiometry” (DEXA or DXA) scan.  This is a test using two low-power x-ray scans that together produce an assessment of bone mass density.  Any bone can be measured, but the test is often at the “femoral neck,” the thin portion of the ball joint in the femur, where it attaches to the hip socket, and a common fracture point.  

DEXA Scan Table (source)



Each DEXA report will show  scores for three areas: 

  1. Lumbar spine
  2. Femur
  3. Total hip

Physical therapists are able to use these scores to identify which areas have more bone loss, and therefore create a treatment plan that is appropriate to the specific needs of the patient.

Two DEXA scores can be shown on the report: T-score and Z-score.  As American Bone Health explains:

  • The T-score compares your bone mass density against that of an average 30-year-old adult (when bone density is about at its peak). 
    •  A T-score of "0" indicates bone density that is average. 
    • "Osteopenia" is defined as a T-score between –1.0 and –2.5 (10%-25% below an average healthy 30 year old adult). 
    • “Osteoporosis” is defined as T-score lower than -2.5 (25% or more below an average healthy 30 year old adult).  
  • The Z-score compares your bone mass density against adults your own age and weight.  

Understandably, these two scores diverge as you get older, and the T-score gets farther and farther away from what is actually a healthy normal.  And neither score accounts for what your bone density was when you were age 30.

Preventing Osteoporosis

“But,” you say, “this doesn’t work!  First you tell me that cancer treatments cause osteoporosis; then you tell me it’s quite hard to know if I really have it, and that if I do, I probably don’t want the treatments!  So what now?”

Fair question.  Consider these facts:

  • Your cancer isn’t a localized issue; it is a stressor on your body as a whole.
  • Conventional cancer treatments (surgery, radiation, chemo) target the cancer as best they can, but all of them are also stressors on your body, as a whole.  Many of these treatments are detrimental to the bones specifically.
  • Anything you do to strengthen your body, as a whole, will also (a) fight cancer, and (b) strengthen the bones.

So, it’s kind of obvious (and even circular), but the true answer here is to not focus on where you fall on some arbitrary scale (Do I have osteopenia or is it osteoporosis now? How bad is my osteoporosis? etc.).  

Instead, ask positive questions, such as:

  • What can I realistically change in my diet, this year, to be more healthy overall for the rest of my life?
  • What exercise routines—of those I am able to do right now—give me the most return on my time investment, in terms of bone-building, de-stressing, and the other goals that are most important for me?
  • What daily habits can I implement (or trim out) to be more relaxed, self-aware, joyful, and well-nourished, and to increase my exposure to what is natural and healthy?

Future blog posts will give some general ideas along these lines (and previous posts have already listed a few).  And of course, you need to take ownership of your health and do as much as you’re able on your own.

But where you need individualized counsel, training, encouragement, tools, and expertise, come talk to us.  At Oncology Rehab and Wellness, we can help you create a plan to maintain (or improve) your bone health and ongoing general wellness after cancer treatments have been completed. 

Please schedule a free 15-minute consultation to learn how we can specifically help you.