Sarcoma is a rare type of cancer that arises in the bone and soft tissue, which includes fat, muscles, blood vessels, nerves and fibrous tissue. Sarcomas can develop in any part of the body, though they are most commonly seen in the arms and legs.
Soft bone sarcoma occuring in the leg
Who is at risk?
There are very few known risk factors for sarcomas. These include:
- Previous radiotherapy treatment
- Family cancer syndromes
- A damaged lymphatic system
Some chemicals are also thought to be associated with sarcoma, though this has not been proven. Smoking, diet and exercise are not linked to developing sarcomas.
*People who think they may be at risk should discuss this with their doctor.
What are the signs and symptoms?
The signs of sarcoma depend on the site where they arise. Patients with bone sarcoma present with the following symptoms.
- Bone swelling and pain which tends to worsen at night
- Develop fractures after minor trauma as the bone is weakened by the tumour
- A new lump that may not necessarily be painful located anywhere in the body that increases in size, and may grow to a large size over time (patients experiencing soft tissue sarcomas)
*A doctor should be consulted should the above symptoms occur.
What can you do to prevent Sarcoma?
Given the limited risk factors, it is difficult to prevent sarcomas. There are no screening tests, and the best approach is for patients with new lumps, or lumps that are increasing in size, to seek medical attention early. This is especially so for patients who have a strong family history of cancer, or patients with previous radiation therapy treatment.
How is Sarcoma diagnosed?
If there are signs and symptoms of sarcoma, your doctor may order some imaging tests. These include, plain x-rays, CT scans, ultrasound scans, MRI scans or even PET or bone scans. The test selected depends on the location of the lump.
After the imaging tests are done, a biopsy is needed to confirm the diagnosis of sarcoma. This can either be done as a needle biopsy, or a surgical biopsy.
Needle biopsies are done using a core biopsy needle. These remove a 1mm core of tissue from the tumour, and can be done in the clinic or under by a radiologist in the radiology centre using imaging guidance. Multiple cores are often needed in order to obtain sufficient tissue for a diagnosis. Fine Needle Aspiration (FNA) biopsies are not used frequently for sarcomas because insufficient tissue is obtained.
Surgical biopsiesmay be required for some tumours, especially bone sarcomas and large soft tissue sarcomas.
Biopsies have to properly planned and should be performed by teams with experience in sarcoma treatment. An improperly performed biopsy may make subsequent removal difficult and may compromise outcomes of treatment.
The specimen taken during the biopsy is processed and reviewed by the pathologist. At times, further these using molecular tests may be required in order to establish the diagnosis.
Once a diagnosis of sarcoma is made, further imaging investigations may be required to complete the staging of the cancer. This helps to assess the prognosis for the patient.
What are the treatment options?
Based on the diagnosis and staging, the team will then recommend the appropriate treatment. The possible modalities for treatment include surgery, chemotherapy and radiotherapy. The treatment is decided by a multi-disciplinary team that includes specialists from all fields involved in patient management.
Radiation therapy makes use of ionising radiation to eradicate cancer cells. It is often used as an adjuvant treatment in support of surgery to further reduce local recurrences of sarcoma. When warranted, it is typically given after surgery when risk factors for recurrence are identified, though it can sometimes be given before surgery. After surgery, the operative and pathological findings are discussed at a multi-disciplinary tumor board to identify risk factors for recurrence and the need for adjuvant radiation therapy.
Chemotherapy is the use of drugs given systemically either into a vein (parenterally) or taken by mouth (orally) to treat cancer. These drugs enter the bloodstream and reach all areas of the body, making this treatment useful for cancer that has spread (metastasised) to other organs.
Depending on the type and stage of sarcoma, chemotherapy may be given as the main treatment, as an adjuvant (addition) to surgery or as neoadjuvant therapy (prior to surgery to downsize the tumor).
The choice of chemotherapy is highly dependent on the type of sarcoma , and usually consists of a combination of several anti-cancer drugs.
The need for chemotherapy will be discussed at a multi-disciplinary tumor board based on investigations and pathological reports available.