If you have metastatic cancer (cancer that’s spread to other parts of your body beyond where it started) to the bones, or multiple myeloma, your healthcare team may have mentioned or recommended some medicines that can help protect your bones. There are a couple different types of bone strengthening injections for cancer patients, and there are some big differences between them.
This post will review two types of these bone strengthening injections, including how they work, how often they are given, and common side effects.
Two Important Types of Cells in Your Bones
Before going into how these medications help your bones, let’s first talk about some specific cells in your bones and how they work to keep your bones always changing.
On the surface of your bones are two types of cells that need to stay in balance to keep your bones healthy.
Osteoclasts break down old bone, and osteoblasts build bones back up.
Our bones are always in this breaking down and rebuilding process, we just don’t notice it.
When each type of cell is working correctly and your body has the right amounts of each, your bones remain healthy and strong.
Cancer and the Bones
Unfortunately, cancer can seriously damage your bones in a number of ways:
- Chemotherapy and radiation can weaken bones
- Some hormonal treatments, like some for breast cancer stop the body from producing estrogen, which typically protects bones. Without the estrogen hormone in your system, bones weaken.
- Cancer can spread, and develop tumors inside bones. This is called secondary bone cancer or bone mets, and these can be painful.
- Multiple myeloma, a cancer of the blood plasma cells, starts in the bone marrow and upsets the balance of the bone breakdown and growth cycle.
Myeloma cells kick osteoclasts into overdrive, which immediately starts to break down bone. At the same time, myeloma cells block
osteoblasts, which means the body can’t rebuild the damaged
bone.
When bones become too weak, they can break easily, even without a big fall or other injury to that part of the body.
This imbalance can also lead to high calcium levels in the body, which can lead to other serious health issues, including death.
Protecting the Bones
Medicines have been created to restore the balance in your bones. This can help prevent them from breaking as easily. These medications can also relieve bone pain from tumors in the bones.
Studies also show that these type of medicines can also fight some types of cancer.
These injections can be given alongside your regular cancer treatment.
There are two primary categories of meds used to prevent and treat serious bone problems in people with cancer:
Monoclonal Antibody
This is a type of targeted therapy that finds and attacks certain protein cells on a tumor. You may have heard of denosumab, or its commercial name, XGEVA®.
This medicine targets a protein called RANKL, which controls the activity of osteoclasts.
By stopping the osteoclasts from growing out of control, it stops the bone cells from being broken down and strengthens the bone.
Both people with multiple myeloma and bone metastases from other types of cancer, including metastatic breast cancer, prostate cancer, and other solid tumors can take this to restore the balance in the bones.
Bisphosphonate
This type of drug also works to restore and protect weakened bones.
Zoledronic acid, or Zometa, is the most well-known drug in this class for bones. It attaches itself to the bone cells to slow down the rate of bone change.
Aredia, or pamidronate disodium, is another bisphosphonate drug option. It works in the same way that Zometa does to reduce and prevent bone damage and bone loss.
Drug Interactions to Be Aware Of
When talking to your health care provider about bone strengthening injections for cancer mets or myeloma, you’ll want to be sure they are aware of all of the other prescription drugs, supplements and over the counter medications you are taking. This is because these bone-strengthening drugs can interact with other medications.
For example, Aredia may interact pain medicines, lithium, IV antibiotics and methotrexate.
Zometa may interact with those same medications, along with water pills and others.
Preparing for Your Injection
You’ll need to have a full dental check up and have any needed dental work, including dental surgery, completed prior to starting treatment.
This is so your dentist can have an idea of how your mouth and teeth look before starting treatment, and make sure you don’t have gum disease.
One of the rare, but very concerning side effects of these type of bone strengthening injections that we’ll review in just a bit affects your jaw, so a thorough dental exam is required to start with to make sure your mouth is healthy before starting the injections.
You’ll also need to have regular dental exams – every three months or so – the whole time you’re receiving treatment and for a while afterwards.
It’s often recommended to avoid any major dental surgeries during the time you’re on this type of injection, and even for a while afterward.
If you do need to have dental procedures, you may be prescribed antibiotics before the work is done to help prevent infections.
Your dentist should be made aware of the type of bone strengthening injections you are on as well.
Practicing good oral hygiene with regular brushing and flossing will be important to keep your mouth and teeth and healthy as possible.
Other Labwork
Additional exams that will be needed before your first injection will be blood tests to check your kidney function and levels of calcium in your blood. These blood tests will be repeated before each treatment too.
If you have low calcium levels, you may be prescribed Vitamin D and calcium supplements to help improve your low blood calcium.
Even if your calcium levels are fine, you may still be prescribed these supplements to help prevent calcium levels from dropping too low.
If you’re taking a bisphosphonate, your phosphate levels will be checked each time too, since these levels can also drop while on treatment.
Treatment Dosing and Scheduling
There are some differences in how and how often these injections are given.
For XGEVA, the typical dose is 120 mg. Injections are given subcutaneously, which is just below the skin. Possible injection areas can include your belly, upper arm, or upper thigh. You’ll go to the doctor’s office or clinic every 4 weeks for the injection.
Zometa’s typical dose is 4 mg. This is given intravenously so it goes straight into your bloodstream. It can be given through a port, a PICC line, a central line or even via a vein in your arm.
The drip usually takes about 15 minutes, but your healthcare provider may increase that time. You’ll go back to the clinic or office every 3-4 weeks for treatment.
Aredia is usually given as a 90 mg dose. This too, is given via an IV. The difference with this drug is that it is a much slower infusion time.
It is given over a minimum of 2 hours, and can sometimes be spread out over up to 24 hours.
For those with bone metastasis of a solid tumor, often a single treatment is given.
For those with myeloma, the standard treatment with this drug is an infusion over 4 hours, given every 4 weeks.
Side Effects
Both of these classes of drugs can cause minor to serious side effects.
While I can’t get into all of the possible side effects, I’ll touch on the ones that seem to be most common, and also a couple that can be of great concern.
Common side effects of bone strengthening injections for cancer mets and myeloma can also vary by drug used.
Side effects of all of these medicines include:
- fatigue (extreme tiredness)
- weakness
- nausea
- GI issues, including constipation or diarrhea
- headache
- bone, joint or muscle pain
- low calcium levels
- anemia (low red blood cell levels)
- kidney problems – your kidneys may not function as well as they used to
Other XGEVA side effects include:
- low phosphate levels
- pneumonia or upper respiratory tract infections
- shortness of breath
- rash
- swelling of legs and/or hands
Other bisphosphonate side effects include:
- flu-like symptoms, which often happen just during the first 1-3 days after the injection
- dizziness
- trouble sleeping
- loss of appetite
- low thyroid levels
- infertility (the ability to have children)
Other Serious Potential Side Effects
Both of these types of drugs can cause some serious side effects:
Broken Bones
It seems a bit backwards, doesn’t it? A medicine to help rebuild and strengthen the bone can lead to broken bones?
But this can happen. Bone fractures, especially in the thigh bone (femur) can happen, even with little to no impact.
After stopping these medicines, some may have a greater risk of fractures of the bones in the spine or spinal cord compression.
Osteonecrosis of the Jaw
Severe jaw bone problems can also occur. This is rare, but very serious. Osteonecrosis means the cells of the jawbone begin to die.
Osteonecrosis of the jaw is more likely to occur if the patient smokes, has dental implants, uses dentures, or has gingivitis.
If you are on these injections and notice gum redness and swelling, loose teeth, jaw pain, or infection, be sure to contact your medical team right away.
Treatment options for this condition include pain medicine, antibiotics and special mouth rinses.
Other Ways to Enhance Bone Health
There are other steps you can take to improve bone health and maybe even make these injections more effective. I’ve already mentioned that calcium and Vitamin D supplements may be recommended by your health care team.
You may also want to eat foods that are calcium rich, including leafy green vegetables, dairy products like milk, yogurt, cheese and cottage cheese, almonds, white beans and sardines.
Regularly engaging in light exercise has also been shown to strengthen bones. Be sure to check with your medical team first – they will have checked your bone density, and can tell you which exercises would be best depending on your current bone health, and which to hold off on until your bone mass has improved.
Which Bone Strengthening Injection for Cancer is Right For You?
Your healthcare team will give their medical advice on which injection is best for you.
This will be determined based on if you have any current kidney disease, how strong your immune system is, and even which parts of the body the cancer has spread to.
They’ll also review your risk factors for developing some of the more concerning side effects.
They’ll also consider any supplements or prescription medicine you might be taking, along with the type of cancer treatment you’re receiving.
This article can keep you informed about the different options and side effects, so that you can be an active participant in making decisions that are best for you.
