Bone cancer is a rare type of cancer, contributing to less than 1% of all cancers. It can begin in any bone in the body, but commonly occurs in the long bones in the arms and legs.
In bone cancer, the cells in the bone start to grow uncontrollably, and destroy the normal bone tissue.
Based on the origin of the cancer, bone cancers can be categorized as follows:
Primary bone cancer
This cancer begins in a bone, either on the surface, in the outer layer or from the centre of the bone.
It is a rare type of cancer, which affects all ages, particularly in people aged 10-25 years and over 50 years. If primary bone cancer is not treated, it can spread to other parts of the body.
Certain types of bone cancer occur mostly in children, and the others affect the adults.
There are several types of primary bone cancers, the most common types are discussed below:
Osteosarcoma: This type of cancer arises in the bone forming cells called osteoblast. Usually, it occurs in the arms (upper arm) and legs (knee), but can affect any bone. This occurs commonly in children and young adults.
Chondrosarcoma: This type of cancer grows in the cartilage. It commonly occurs in the upper arms, shoulder blades, ribs, pelvis, and legs. It usually affects middle-aged and older people.
Ewing Sarcoma: This cancer usually arises in the bone or in the soft tissues around the bones. It commonly begins in the leg bones and in the pelvis, but it can occur in any bone. This type of cancer is common in children and young adults.
Secondary bone cancer
This type of cancer means that the cancer started in another part of the body (for example, breast or lung) and has spread to the bones.
Non-cancerous bone tumours
These do not spread to other parts and are more common than cancerous bone tumours.
What are the causes and risk factors?
The exact cause of most bone cancers is not known. However, some factors have been found to increase the risk of bone cancers. These are discussed below:
Inherited genetic syndromes
Rare genetic syndromes, can increase the risk of bone cancer. These syndromes include Li-Fraumeni syndrome and hereditary retinoblastoma.
Previous cancer treatment with radiation therapy or chemotherapy
Exposure to large doses of radiation, such as those given as a part of radiation therapy to treat other cancers, increases the risk of bone cancer. Certain chemotherapy drugs can also increase the risk of bone cancer.
Individuals who have Paget’s disease of the bone, are at a higher risk for developing bone cancer.
What are the signs and symptoms of bone cancers?
Pain is one of the most common symptoms of bone cancer, which gradually becomes constant and does not improve with pain killers. Other symptoms include:
- Swelling over affected part of the bone
- problems with moving around, such as an unexplained limp
- loss of feeling in the affected limb
- Weak bone leading to fracture
- unexplained weight loss
Stages and grades of bone cancer
Knowing the grade and stage of the bone cancer, helps your healthcare team select the treatment plan most suitable for you.
The grade of the cancer suggests how quickly the cancer may grow. This can be categorised as follows:
The cancer cells appear similar to the normal cells. These cancer cells grow slowly and are less likely to spread.
The cancer cells appear very different from normal cells. These cancer cells grow quickly and are more likely to spread.
The stage of a cancer indicates how far the cancer has spread in the body. There are different staging systems used for bone cancer.
The stages of bone cancer are indicated by Roman numerals, ranging from 0 to IV. The lowest stages indicate that the tumour is smaller and less aggressive and stage IV means the cancer has spread to other parts of the body.
How is bone cancer diagnosed?
These can help determine the location and size of the bone tumours, and evaluate if the tumours have spread to other parts of the body. Based on the signs and symptoms different imaging tests may be recommended, such as bone scan, computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), X-ray.
In this test, a sample of the tissue will be removed from the tumour, to determine whether the tumour is cancerous, its type and grade. The different types of biopsies used to diagnose bone cancer are:
- Needle biopsy: This involves inserting a needle through your skin and into a tumour to remove small pieces of tissue from the tumour.
- Surgical biopsy: During a surgical biopsy, your doctor makes an incision through your skin and removes either the entire tumour or a portion of it.
These may be recommended to determine the levels of alkaline phosphatase and lactate dehydrogenase. High levels of these enzymes may be present in individuals with osteosarcoma or Ewing sarcoma.
What are the treatment modalities?
The treatment for your case of bone cancer depends on the type and stage of the cancer, overall health and personal preferences. The following are the treatment options for bone cancer.
The aim of the surgery is to remove the entire tumour.
The most commonly performed type of surgery is called limb sparing surgery in which the tumour affected part of the bone along with a small portion of healthy tissue surrounding it is removed.
The bone that is removed is replaced with a metal implant (prosthesis) or a bone graft. A graft uses a piece of healthy bone from another part of your body or from a bone bank.
If the cancer is very large, or is located in a complicated region, all or a part of the limb may be removed. An artificial limb will be fitted in case of amputation.
In this treatment, anti-cancer drugs are delivered intravenously to kill the cancer cells.
Chemotherapy works better for osteosarcoma and Ewing sarcoma; it is not very effective for chondrosarcoma.
In this treatment, high-energy radiation, such as X-rays, are used to kill cancer cells.
It is used before surgery to shrink the tumour and make it easier to remove, and thereby reduce the need for amputation.
Radiation therapy can also be used to treat bone cancer in patients who cannot undergo surgery. It can also be used after surgery to kill any cancer cells that may be left behind.
What are the possible complications/side effects?
The side effects of the treatment depends on various factors, including the treatment received, the patient’s age, etc.
Some side effects of surgery include:
- surgical site infection
- implant failure.
Common side effects of chemotherapy include fatigue, risk of infection, nausea and vomiting, hair loss, loss of appetite, and diarrhea. Most side effects associated with chemotherapy should resolve once your treatment is completed.
The side effects of radiation therapy will depend on the type and location of cancer, the dose of radiation being given, general health of the patient, effect of other cancer treatments, such as surgery and chemotherapy. Also, the severity of side effects may differ from patient to patient.
Side effects may include mild skin reactions, tiredness, hair loss in the body part being treated. Most side effects go away soon after treatment is finished.
You can read more about the side effects of radiation therapy here.
What is the prognosis of bone cancer?
The prognosis or survival differs for every patient, and it is affected by several factors. One of the most important factors is whether it has spread to other parts of the body. For example, patients who have metastatic osteosarcoma or Ewing sarcoma have a 5 year survival rate of only 25% to 35%; on the other hand, it is 70% to 80% for localized disease.
You can watch Dr Satish Reddy explain the treatment for bone cancers here.