“Sometimes we see involvement of one or two bones at initial diagnosis of non-small-cell lung cancer,” says Amy Cummings, MD, a thoracic oncologist at the David Geffen School of Medicine at the University of California in Los Angeles. “Bone metastasis can also occur later on as a progression event.” Unlike bone cancer, which originates in the bones, bone metastases from lung cancer happen when cells break off from the original tumor in the lungs and travel through the bloodstream or lymph system to the bones. Once there, the NSCLC cells turn on osteoclasts, which are bone cells that normally dissolve small bits of bone to help remodel them and keep them strong. When osteoclasts become overactive, though, they create tiny holes or pockets in the bone, where the cancer cells can then take up residence, explains Dr. Cummings. This can lead to pain and weakness in the bone. While NSCLC can travel to any bone in the body, it most commonly spreads to large, centrally located bones, such as the spine, ribs, and pelvis. It may also spread to the long bones of the arms and legs. For most patients, metastatic NSCLC can’t be cured, but new advanced treatments can significantly lessen symptoms and lengthen life. In addition, finding and treating bone metastases early can prevent problems, such as fractures, from occurring later on.
Signs that Metastatic NSCLC Has Spread to the Bones
While it’s possible to have bone metastases without experiencing any symptoms, these are some common signs. Bone pain “The most common symptom of bone metastases is an achy pain, often coming from the chest, back, or hips, that tends to be worse in the morning after you first wake up,” says Cummings. Over time, the pain may become severe. While not all pain means metastasis, it’s important to tell your cancer care team about any new, unexplained pain that doesn’t get better with rest. Broken bones Bones weakened by metastatic cancer can break or fracture. This might happen from a fall or injury or what doctors refer to as a pathological fracture, which happens during ordinary activities, such as coughing, stepping out of a car, or bending over. A fracture often causes sudden, severe pain that doesn’t let up and can sometimes make it hard to move. Numbness and weakness Cancer growth in the spine can squeeze or press on the spinal cord, called spinal cord compression, and can be serious. The spinal cord has nerves that allow you to move and feel what happens to your body. If the nerves are compressed, it can cause numbness and weakness in the area of the body below the tumor. Spinal cord compression can also cause difficulty urinating and controlling your bowel movements. If you have any of these symptoms, let your team know right away. Left untreated, spinal cord compression can result in paralysis. Extreme thirst, loss of appetite, or sluggishness As cancer cells damage the bones, calcium is released into the blood. This can lead to high blood calcium levels, or hypercalcemia, according to the American Cancer Society (ACS), which can cause you to make more urine, leading to dehydration. It can also cause extreme fatigue or sleepiness, nausea, and loss of appetite. If you experience any of these symptoms, alert your medical team right away. Left untreated, hypercalcemia can lead to complications such as osteoporosis, kidney stones or kidney failure, difficulty thinking or concentrating, and even coma. If you report any of the above symptoms to your doctor, they will likely order imaging tests, such as a CT (computed tomography) or PET (positron emission tomography) scan, to look for bone metastases, says Cummings. Depending on the results, your doctor may also order an MRI (magnetic resonance imaging) or tissue biopsy to confirm the diagnosis.
How Are Bone Metastases Treated?
Current treatments typically don’t cure metastatic NSCLC, but they can help shrink tumors, stop or slow the spread of the cancer, and relieve pain and discomfort. “Treating non-small-cell lung cancer that has spread to the bones involves a two-pronged approach: treating the cancer itself and also stopping the breakdown of bone and strengthening any areas of bone that have been weakened,” explains Cummings. Your treatment plan may include the following. Systemic cancer treatment Some of the same methods your doctor uses to treat NSCLC in your lungs can also shrink bone tumors and relieve the pain of bone metastases. Depending on the particular characteristics of your cancer, this may include immunotherapy drugs, chemotherapy, or targeted medications. You should also consider clinical trials if you have advanced lung cancer with metastases, particularly if your current therapies aren’t adequately controlling the disease, notes Cummings. Bone-modifying medications Drugs called osteoclast inhibitors can treat cancer that has spread to the bones. They do so by slowing down the action of osteoclasts, thereby slowing or preventing tumor growth in the bones. This can reduce bone damage and pain as well as hypercalcemia, notes the ACS. Ablation A technique done by interventional radiologists — doctors who use imaging, such as fluoroscopy, MRI, CT, and ultrasound, to guide minimally invasive surgical procedures to diagnose and treat diseases — ablation involves putting a small needle or probe right into the bone tumor and then using heat or cold to destroy it. Ablation is often used if only one or two bone tumors are causing problems, according to the ACS. After the cancer tissue is destroyed, the space left behind may be filled with bone cement. Surgery If a bone has fractured or is very weak and at risk of fracturing, you may be referred to an orthopedic surgeon, who can insert a rod or pin to stabilize the bone, says Cummings. Spinal fractures or compression are sometimes treated with an outpatient procedure called vertebroplasty, in which a quick-setting bone cement is injected into a collapsed vertebra to build it back up and help relieve symptoms. Palliative care This type of specialized medical care focuses on relieving symptoms, mitigating any side effects of treatment, and improving overall quality of life. It may include pain medications, radiation therapy, physical therapy, exercise, relaxation and stress-relief techniques, and acupressure or acupuncture. Talk to your team about all the palliative care options available at your center. Information and support for people with lung cancer and their families is also available at the ACS, the Go2 Foundation for Lung Cancer, and the Global Resource for Advancing Cancer Education (GRACE).
