Lung Cancer & Bone Health: What You Need to Know

When lung cancer spreads, your bones are one of the most likely places for it to go. Cancer cells release substances that can cause pain in the bones, weaken the bones, and increase the risk of fracture. The cancer cells can also grow within the bone, and this causes bone damage as the cancer cells enlarge and remove calcium from the bones.

"A major issue with lung cancer is bone metastasis and fracture," says Sandip Patel, MD, a medical oncologist who specializes in lung cancer at UC San Diego Health.

Cancer cells can also make your bones release calcium into your bloodstream faster than they should. Your bones need to hold onto this calcium to stay strong. Letting go of too much calcium, which is called hypercalcemia, weakens your bones, and may cause other systemic symptoms throughout your body when blood calcium levels become higher than normal. Hypercalcemia can be dangerous, but there are effective treatments if your calcium level becomes too high.

One crucial thing to keep in mind is that there's a difference between bone metastasis and bone cancer. The former refers to the spreading of cancer to the bones that may have originated elsewhere (from the lungs to the bones), and the latter refers to cancer that has primarily originated in the bones.

Diagnosing bone metastasis

If your doctor suspects your cancer has metastasized to the bones, they will prescribe one or more of the following tests to get an accurate diagnosis:

• Imaging tests (X-ray, MRI, PET scan, bone scan)
• Blood tests (Complete blood count (CBC) or Comprehensive metabolic profile (CMP))
• Tissue biopsy to examine the cells of your tumor under the microscope

Signs and symptoms

The most common sign and symptom encountered by bone metastatic patients is pain. Apart from that, they may experience a wide range of symptoms that result from where the tumor is lodged. For instance, if the tumor is on or near the spinal cord, it can affect mobility and cause numbness and weakness. Cancer in the bone causing compression of the spinal cord is a medical emergency and requires treatment right away.

Other common symptoms include the fragility of bones and susceptibility to fractures and breaks even during normal activities like walking, sitting, getting out of a car, etc.

A less common symptom patients with bone metastasis may experience is increased thirst, reduced appetite, constipation, and feeling lethargic. This happens because one of the complications of bone metastasis is calcium increase in the blood, which can lead to the previously mentioned symptoms, or cause nausea and fatigue as well.

Causes of bone metastasis

To this day, there's no known reason why some cells decide to migrate and spread to other organs while other cells stay localized. It's also not clear why some lung cancer cells spread to the liver or bone while other lung cancers metastasize to the brain.

Complications

As bone metastasis progresses into advanced stages, some complications need to be taken into consideration so that they don't pose further discomfort or danger to your health as a patient. These complications include the following:

Hypercalcemia

As the calcium levels in the blood keep increasing, it can cause many discomforting symptoms like we previously mentioned, but when that level keeps rising, it can also cause several serious health conditions. Hypercalcemia is often a late manifestation of bone metastasis but it can be serious and your treatment team should monitor you for any signs or symptoms of high calcium levels.

Anemia

Occasionally, in patients with extensive disease, the bone marrow may be effected leading to anemia. Anemia is a condition where your red blood cell count is decreased. Signs and symptoms of anemia include fatigue, shortness of breath, tiredness, and pallor.

Pathological Fractures

Pathological fractures are a type of fracture that happens randomly without any reason. It can occur during everyday life. This is caused when the bones become weakened. Pathologic fractures can cause significant pain, reduced mobility and negatively impact quality of life. Most pathologic fractures are treated with a combination of surgery to stabilize the damage and radiation to kill the remaining cancer cells.

Cauda Equina Syndrome and Cord Compression

This is considered one of the most serious complications of bone metastases. In fact, it's so serious that it requires immediate medical intervention. This condition happens as a result of metastatic spinal cord compression that can develop spinal cord injury, necrosis, vascular injury, and irreversible damage.

If not treated, cauda equina syndrome and cord compression can result in loss of reflexes in the legs and loss of bladder and bowel control. It can also cause severe pain and difficulty with walking. Some patients may also have issues with sensation and may note numbness or tingling in an extremity or other part of the body.

Be sure to follow up with your doctor and share any symptoms that you may experience so they can put the best plan of treatment suitable for your needs.

What is the treatment for lung cancer that has spread to bones?

When lung cancer patients develop metastatic diseases, there's typically no cure. However, doctors can attempt to help manage symptoms and make patients as comfortable as could be. This is known as palliative treatment which aims to improve the quality of life for lung cancer patients and alleviate the symptoms.

Dr. Ishwaria Subbiah, a medical oncologist and palliative care physician at the MD Anderson Cancer Center, shared a fascinating experiment from 2009 (published in 2011): rather than trying to eliminate the deeply ingrained end-of-life connotations of the term "palliative care," Dr. Subbiah's colleagues at MD Anderson decided to change the name altogether, rebranding their palliative care center as the "Supportive Care Clinic."

"We found out that the name was a big barrier to referrals," Dr. Subbiah said. "The name itself was a barrier to accessing our services."

Nevertheless, it's important to note that not all patients are the same; some cases of bone metastases have a better prognosis than others. In these cases, doctors may try some aggressive approaches to fight off cancer and increase patients' overall survival.

Treatment options are categorized into localized treatments and systemic treatments. These potential treatments include:

• Pain killers. Analgesics or opioids include non-steroidal anti-inflammatories (NSAID), morphine, or hydrocodone, among many others. These medications work through different mechanisms to stop pain on many fronts. Often, doctors will combine pain medications to achieve the best control for each patient.
• Corticosteroids. These are used to treat inflammation and ease the pain. Examples include dexamethasone and prednisone.
• Radiation therapy. Radiation therapy is very effective in reducing pain in patients with metastasis. Approximately 70-80% of patients treated with radiation will have improvements in their pain and close to half may have complete relief from pain. Radiation can also help in reducing the pressure of spinal cord compression or other more serious sites of involvement. Side effects from radiation therapy include fatigue and possible skin irritation.
• Osteoclast inhibitors. These include a class of drugs known as bisphosphonates that stop bones from breaking down and protect them from being destroyed or fractured. Side effects include fatigue, reduced appetite, vomiting, and fever. Another serious side effect of this treatment is a condition called osteonecrosis of the jaw (ONJ), which results in cutting the blood supply to the jaw rendering it susceptible to infections.
• Surgery. Surgery is typically used to increase bone stability by adding screws to prevent them from breaking down and improve physical function. Doctors can also try and remove some or all of the tumor if it's accessible. Oftentimes patients will also get radiation after surgery.
• Chemotherapy. Toxic drugs can help in shrinking the tumor or slowing its progression. But there are some side effects associated with this treatment like losing hair, tiredness, infections, nausea, reduced appetite, vomiting, diarrhea or constipation, and sores in the mouth.
• Targeted therapy. Include specific proteins that can target certain markers on cancer cells and binds to them to either inhibit their growth or cut off their nutrition source. Before using this treatment method, your doctor will probably conduct biomarker testing first to assess the presence of these markers. Side effects of this treatment can vary from patient to patient, and they depend on the type of drug used.
• Immunotherapy. This class of medications works with the immune system cells and stimulates them to find cancer and attack it. The most serious side effects included with this treatment are autoimmune reactions and allergic reactions.

Palliative treatment. These include practices that focus only on easing your symptoms and managing your pain. Here are some examples of these practices:

• Physical therapy
• Acupuncture
• Relaxation and stress-relief techniques
• Exercise
• Eating healthily

What can you do to improve bone health?

According to the American Lung Cancer Association (ALA), the 5-year-survival rate for lung cancer that has spread to other parts of the body is low. However, it all depends on the state of the patient and treatment response.

Some things can weaken your bones and lead to breaks that are simply out of your control. But there are other things you can control that have a big impact on bone health.

"Weight-bearing exercise and vitamin D supplementation help maintain the bone health of people who have lung cancer," Dr. Patel says.

Weight-bearing exercise is a physical activity that requires you to support your body weight, such as brisk walking, running, and dancing. That helps your bones hold on to the strength they need to support you. If you quit making this demand on your bones, they can become weak, brittle, and prone to breaks. Swimming and biking are good for your heart, but they don't help your bones.

"Exercise using your body weight is generally fine as long as it doesn't cause you any pain," Patel says.

Vitamin D helps your body absorb calcium. Your bones need calcium to stay strong. You can get vitamin D from the sun, from certain foods, and from supplements. Adults from ages 51 to 70 should get 600 IUs a day from food or supplements. (The sun isn't a great source of vitamin D if you wear sunscreen to avoid skin cancer or don't get outdoors much.) After age 70, you need 800 IUs of vitamin D a day.

Here are other things you can do to keep your bones healthy and strong:

• Maintain a healthy weight; underweight people have a greater risk of bone breaks
• Limit drinking to no more than two drinks a day
• Quit smoking; smokers have a higher risk of osteoporosis

The bottom line

Lung cancer, along with breast and prostate cancers, is among the cancers most likely to spread to the bones. When cancer cells spread to your bones, it can cause pain, bone weakening or breaks, and overall damage to your bone health. But there are treatments to help slow the growth of cancer as well as treatments for your bone symptoms.

You can take steps to maintain your bone health with lung cancer, too. Aside from following treatments, there are some recommended practices that you can undertake that can significantly change the outlook of your response.

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