Bone cancer develops in the skeletal system and destroys tissue. It can spread to distant organs, such as the lungs. The usual treatment for bone cancer is surgery, and it has a good outlook following early diagnosis and management.
The two main types are primary and secondary bone cancer. In primary bone cancer, cancer develops in the cells of the bone. Secondary bone cancer occurs when cancers that develop elsewhere spread, or metastasize, to the bones.
According to the National Cancer Institute, primary bone cancer accounts for less than 1% of all cancers. Secondary bone cancer is more common.
In this article, we will discuss the survival rates, types, causes, and symptoms of bone cancer, as well as possible treatments.
There are several types of bone cancer.
Primary bone cancers
Tumors in the bone are either benign (noncancerous) or malignant (cancerous). Benign tumors do not spread beyond their original site. Malignant tumors are more aggressive and have a higher risk of growing and spreading.
Examples of benign bone tumors include:
- osteoid osteoma
- aneurysmal bone cyst
- fibrous dysplasia of the bone
Osteoblastoma and giant cell tumor of bone may become malignant after starting as benign. They will usually become aggressive without spreading to distant sites and cause damage to the bone near the tumor.
Examples of malignant primary bone tumors include:
- Ewing’s sarcoma
- malignant fibrous histiocytoma
- other sarcomas
Multiple myeloma is a blood cancer that may lead to one or more bone tumors.
Certain bone cancers develop in specific bones. For example, teratomas and germ cell tumors mainly occur in the tailbone.
This type of cancer develops in osteoblasts, which are the cells that form bones.
Osteosarcoma is the most common type of bone cancer. According to St. Jude’s Children’s Research Hospital, children and adolescents aged 10–19 years have the highest risk of osteosarcoma, and it is the third most common cancer among teens in the United States.
Having Paget’s disease of the bone, which is a disease that causes excessive bone growth, also increases the risk of osteosarcoma.
Ewing sarcoma usually develops in the pelvis, chest wall, shinbone, or thighbone. However, it might also develop in supporting soft tissue, such as fat, muscle, or blood vessels.
This is a rapidly growing tumor that often spreads to distant sites in the body, such as the lungs. It is most common in adolescents between 10–19 years of age. Although it is the second most common type of bone cancer in children and teenagers, it is very rare.
Chondrosarcoma usually develops in adults. It starts in cartilage, a type of connective tissue that lines the joints, and then spreads to the bone.
Most commonly, it develops in the upper leg, pelvis, and shoulders. Chondrosarcoma usually grows slowly.
This is most common in adults over the age of 40 years.
This is a very rare cancer of the spine. It usually develops at the bases of the spine and skull in older adults.
Children and adolescents can also develop chordoma. When this occurs, chordoma usually begins to grow at the base of the neck and skull.
Secondary bone cancers
These are the most common bone cancers in adults.
They develop when a cancer spreads to the bone from elsewhere in the body. Most cancers can spread to the bones. However, people with breast and prostate cancer have a particularly high risk of developing secondary bone cancer. Doctors know this as bone metastases.
The type of treatment for bone cancer depends on several factors, including:
- the type of bone cancer
- its location in the body
- how aggressive it is
- whether it has spread
There are several approaches to treating bone cancer.
Surgery aims to remove the tumor and some of the bone tissue that surrounds it. It is the most common treatment for bone cancer.
If a surgeon leaves some of the cancer, it may continue to grow and eventually spread.
Limb sparing surgery, or limb salvage surgery, means that surgical intervention occurs without having to amputate the limb. However, for a person to use the limb again, they may need reconstructive surgery.
The surgeon may take bone from another part of the body to replace lost bone, or they may fit an artificial bone.
In some cases, however, a doctor may need to amputate a limb to remove the presence of cancer altogether. This is becoming increasingly rare as surgical methods improve.
Radiation therapy is common in the treatment of many cancers.
A specialist targets cancer cells with high-energy X-rays to destroy them.
A person may receive radiation therapy alongside surgery. People who do not need surgery for bone cancer might also be candidates for radiation therapy.
It is a standard treatment for Ewing sarcoma and a regular part of combination treatment for other bone cancers.
Combination therapy is radiation therapy combined with another type of treatment. This may be more effective in some cases.
Chemotherapy involves using medications to destroy cancer cells.
People with Ewing sarcoma or a new diagnosis of osteosarcoma usually receive chemotherapy.
A doctor may also recommend a combination of chemotherapy and radiation therapy.
This technique sometimes replaces surgery to remove tumors from bone tissue. A surgeon targets cancer cells with liquid nitrogen to freeze and destroy them.
This treatment uses a drug that scientists have designed to interact specifically with a molecule that causes cancer cells to grow.
Denosumab (Xgeva) is a monoclonal antibody that doctors use in targeted therapy. The U.S. Food and Drug Administration (FDA) have approved it for use in adults and adolescents with fully developed skeletons.
Denosumab prevents osteoclasts, which are a type of blood cell, from destroying bone tissue.
Staging and grading a bone tumor allows doctors to decide on the best course of treatment and the most likely outlook.
Grading involves looking at the cells of the tumor under a microscope and assessing how they differ from healthy bone tissue.
A grade 1 tumor has cells that resemble bone tissue, while a grade 3 tumor has more abnormal cells that suggest a more aggressive cancer.
Staging a tumor indicates its size and spread. Several different characteristics can constitute the different stages, so each stage has two substages apart from stage 3.
The tumor measures either less or more than 8 centimeters (cm) across and has not spread from its original site. It is low grade, or the doctor has not been able to determine the grade through testing.
Stage 1 is the most treatable stage of bone cancer.
A stage 2 tumor can be the same size as a stage I tumor, but the cancer is a higher grade. This means that it is more aggressive.
Tumors have developed in at least two places in the same bone have not yet spread to the lungs or lymph nodes. A stage 3 bone tumor would have a high grade.
This is the most advanced form of bone cancer.
A stage 4 tumor will appear in more than one location and will have spread to either the lungs, lymph nodes, or other organs.
The stage of the cancer will dictate the method of treatment and the overall outlook.
While scientists need to carry out more research into the precise cause of bone cancer, the American Cancer Society state that there is a range of risk factors for bone cancer, including genetics. They also indicate that people with long term inflammatory diseases, such as Paget’s disease, might be at a slightly higher risk of developing bone cancer later in life.
However, it is not yet clear why one person gets bone cancer while another does not.
Other risk factors for developing bone cancer include:
- being under 20 years of age
- exposure to radiation, such as receiving radiation therapy for a different cancer
- a previous bone marrow transplant
- having a close relative with bone cancer
- individuals with hereditary retinoblastoma, a type of eye cancer that most commonly develops in children
The first symptom for a person with bone cancer is nagging, persistent pain in the affected area. Over time, the pain gets worse and more continuous.
For some people, the pain is subtle. An individual experiencing this pain may not visit a doctor for several months.
The progression of pain with Ewing sarcoma tends to be faster than in most other bone cancers.
- swelling in the affected area
- weak bones that lead to a significantly higher risk of fracture
- unintentional weight loss
- a lump in the affected area
Although much less common, a person with bone cancer might also experience fever, chills, and night sweats.
A doctor may order a blood test to rule out other possible causes. They will then refer the person to a bone specialist. An individual may need the following diagnostic tests:
- Radionuclide bone scan: This can show whether cancer has spread to other bones. It can identify smaller areas of metastasized cancer than X-rays.
- CT scans: These can indicate whether the cancer has spread and how far.
- MRI scan: This type of scan can provide an outline of the tumor.
- PET scan: This can be useful for scanning the whole body for cancer.
- X-rays: Bone cancer will show on most X-rays. A chest X-ray can also show if the cancer has spread to the lungs.
To grade and stage a tumor, as well as assessing whether it is benign or malignant, a doctor may request a biopsy.
Several different types are available for people with bone cancer, including:
- Fine needle aspiration: The doctor extracts a small amount of fluid and cells from a bone tumor and sends it to a laboratory for viewing under a microscope. They may need a CT scan to guide the needle.
- Core needle biopsy: The doctor uses a larger needle to extract more tissue.
- Incisional biopsy: The doctor cuts through the skin under general anesthesia to remove a small amount of tissue for analysis.
- Excisional biopsy: The doctor removes the whole tumor under general anesthesia for analysis.
The outlook for a person with malignant bone cancer depends mainly on whether it has spread to other parts of the body.
The 5-year survival rate is the percentage of people with bone cancer (reported by stage) who are likely to survive to at least 5 years after diagnosis.
For example, a person with chondrosarcoma that has not spread has a 91% chance of surviving for 5 years after diagnosis.
However, if the cancer spreads to distant sites, such as the lungs, the 5-year survival rate reduces to 33%. Taking all stages into account, the American Cancer Society puts the 5-year survival rate at 80%.
Early detection and treatment is key to improving the outlook.