Can Cancer Treatments Cause Osteoporosis?

By Cheryl Guarna | January 17, 2022

At Oncology Rehab and Wellness, we believe that using physical therapy for Osteoporosis is the most effective treatment method for whole-body and long-term health.  To help explain why, let's take a look at what Osteoporosis is, how it affects women and men, why some cancer treatments can increase the risk of osteoporosis, and how physical therapy is unique in its low-risk and high-benefit results.

What is Osteoporosis?

Osteoporosis has begun when bone tissue in the body becomes too “porous” and therefore too fragile.  Bones are designed with pores, like a dense sponge, to give them some flexibility.  But when the pores grow too large, fracture becomes more likely.

Bones are alive and active.  Bone tissue contains both “osteoclasts”—cells that break down and recycle other bone cells—and “osteoblasts”—which build new bone cells.  Both kinds are always at work.  In fact, about 5-7% of your bone mass is broken down and rebuilt each week.  The body is constantly repairing and strengthening.  

In your younger years, the osteoblasts are more active, building bone density until about age 30.  Later on in life, for a variety of reasons (especially menopause, in women), the osteoblasts tend to be less active than the osteoclasts, which leads to a slow decrease in bone density.  This is normal and not particularly dangerous on its own; but risk increases with other contributing factors such as: 

  • Smoking
  • Alcohol use
  • Insufficient intake of calcium, magnesium, vitamin D, and vitamin K
  • A diet that creates too much acid in the body 
  • Too little physical activity

Bone Remodeling (source)

For additional information on what osteoporosis is and what causes it, see the recent blog article “Physical Therapy for Reversing Osteoporosis.”

Are Men at Risk for Osteoporosis?

While osteoporosis is more common in women (especially post-menopausal), this is not just a “female problem.”  One in four osteoporosis patients is male.  As EverydayHealth.com reports: “The reality is that 80,000 men experience osteoporosis-related fractures every year, and close to 23,000 die as a result of fracture-related complications.”  The misperception among doctors that it’s a “woman-only thing” actually results in underdiagnosis in men, which can lead to delayed intervention.

What Male Cancers Lead to Osteoporosis?

Although bone cancer itself is rare (less than 1%), other cancers may sometimes metastasize into bone tissue.  This can cause a host of issues.

But the more common concern is cancers in other parts of the body that steal minerals from bones or in some other way result in bone loss.  Many cancers and their treatments are linked to sex hormones.  Testicular and prostate cancers (among others) are boosted by sex hormones (in men, this means testosterone and other androgens).  

Therefore, many cancer treatments work to reduce levels of these hormones, either through drugs or sometimes even via surgical removal of a testicle.  While this can slow the cancer growth, the impact on the skeletal system is not good—because these same hormones also play a major role in bone rebuilding.  

So, if your sex-hormone-producing glands or tissues are compromised, either by a cancer itself, or by the treatments applied to that cancer, there’s a good chance your bones will pay the price.

What Cancer Treatments Increase Risk of Osteoporosis?

Believe it or not, the issue is even more complex than just hormones.  Even apart from how they impact hormone production, many cancer treatments contribute to bone loss because they tend to slow down the osteoblasts and ramp up the osteoclasts.  For more detail, see this Futurity article on “cell senescence,” which says bluntly that after cancer therapy, “bone-building cell activity slows down, and the activity of cells that remove old bone actually accelerates.”  

Another study shows that following radiation therapy for colorectal cancer, patients were about 40% more likely to experience a hip fracture 2-4 years after treatment.  So, unfortunately, many conventional cancer treatments can contribute to osteoporosis, and in multiple ways.

The list of cancer treatments that can negatively affect bone mass density (BMD) is long, but some of them include:

  • Hormonal therapy such as androgen deprivation therapy
  • Chemotherapy with doxorubicin or cisplatin
  • Glucocorticoids and certain kinds of steroids
  • Aromatase inhibitor (AI) therapy (source) – drugs such as exemestane, letrozole, and anastrozole
  • Gonadotropin-releasing hormone (GnRH)
  • Bone marrow transplant
  • Stem cell transplant
  • Radiation therapy (localized to radiation site; worst effects often delayed by several years)
  • Any treatment that requires or creates reduced movement & physical activity

Finally: loss of appetite is a common side effect of chemotherapy, which makes maintaining a good diet that much harder.  And various cancer-related drugs, such as nausea-reducing medications, can also cause loss of bone density (source).

Osteoporosis (source)

A Word of Caution

While osteoporosis is an issue, and under-diagnosis/under-treatment is real, it is also possible to over-diagnose and over-treat, which causes opposite sorts of problems.  Here are a few facts to consider:

  • “Bone mineral density” is not necessarily the same thing as, nor the sole measure of, “bone health.”
  • A modest decrease in bone mass is a normal part of the aging process and is not highly risky.
  • In women, “low bone mineral density is associated with a lower local and distant rate of [breast cancer] recurrence” whereas high bone density correlates with a higher likelihood of breast cancer recurrence (PubMed).  
  • So, pursuing high bone density by artificial means will likely have unintended side effects, which may impact heart health, etc.  For example:
    • Taking too much calcium, using a type with low bioavailability, or taking calcium out-of-balance with other vital minerals, can lead to risk of calcified arteries and other cardiovascular issues.
    • There are many drugs that are “proven” to increase bone mass density—such as Fosomax and similar bisphosphonates—but there are costs that may not be worth paying.  Side-effects can include gastrointestinal toxicity, a suppression of bone-tissue turnover, and even osteonecrosis (bone death) in the jaw (PubMed).  So, while bone density may be increased by these drugs, bone health (and heart health!) can actually be harmed.

In short: getting a DEXA scan, worrying that your bone density is less than when you were 30 years old, and running out to get prescription meds or mega-doses of cheap calcium supplements is NOT the course you want to take!

So then, what is?

Using Physical Therapy to Treat Osteoporosis

For a basic list of dietary and lifestyle adjustments that can help prevent/reverse bone problems (see the blog article “Using Physical Therapy for Treating Osteoporosis in Cancer Patients.”)  And in a later blog post, we’ll talk more about specific dietary considerations that will be beneficial for bone health and for combating cancer.  You can also review our page about the nutrition services that we provide at ORW.

But here, we want to talk specifically about the benefits of using physical therapy for osteoporosis.

Targeted physical therapy is perhaps the best first response against osteoporosis, for multiple reasons:

  • It is lowest-risk—much lower risk than bone-density drugs, and almost zero-risk under the care of a qualified physical therapist.
  • It is inexpensive, when compared against the multiple costs of a fracture.
  • It provides holistic care by strengthening the cardiovascular system, the musculature, and the brain, in addition to the skeletal structure.  Proper exercise also builds balance, improves mood, and activates the lymphatic system and other detox pathways in the body.

At ORW, our licensed PTs will assess your specific condition and assemble the best regimen for your specific needs and concerns.  At various points in our four-Phase BEST program, we will carefully calculate the best exercises for you, and train you in some or all of the following types of exercises:

  • Resistance – working bones and muscles against an opposing weight or force—because stress on bone builds bone mass, just like stress on muscle builds muscle mass.
  • Weight-bearing – walking, using an elliptical machine or stair-climber, or using a rebounder (mini trampoline) daily can help exert positive stresses on the bones, triggering rebuilding.  NASA has used these types of exercises to help astronauts recover from the “deconditioning” experienced in zero-gravity (study).
  • Balance – these exercises are not focused on building bone mass as such, but rather on improving balance to avoid falls and breaks.
  • Cardiovascular exercises - Not only is the heart strengthened through sustained, rigorous movement, but these activities also harden the bones.  Cardiovascular endurance can be built with or without exercise equipment and include walking briskly, running, cycling, swimming, and bodyweight exercises. We can create a plan for the cardiovascular exercises that are safest for you.
  • Postural exercises - Improving the strength of the body's trunk will increase the ability to balance and decrease the risk of falling.  These exercises can be done at home without equipment, and we can create a daily core strengthening routine for you.

At Oncology Rehab and Wellness, our team helps cancer patients with condition-appropriate PT.  To learn more, schedule a free 15-minute consultation.

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