There are more than 50 subtypes of sarcoma that develop in the connective tissues – bone, muscle, tendons, nerves, fat, cartilage and blood vessels – each requiring different treatment and needing highly specialised multidisciplinary care.
In most cases, the cause of sarcoma is unknown. Increased risk includes exposure to radiation and chemical carcinogens, including radiation and chemotherapy for treatment of a previous cancer.
Several genetic disorders that run in families can also predispose a person to sarcoma, including Li-Fraumeni syndrome, neurofibromatosis, Gardner syndrome and retinoblastoma. There is also a heightened risk if other family members have had sarcoma.
Sarcomas are usually noticed when a lump appears on the leg, arm or elsewhere on the body, but can also be found during examinations of other symptoms, or during a routine operation. The earlier sarcoma is diagnosed the better the chances of successful treatment.
A specialist doctor may also diagnose sarcoma through a number of tests, including:
- Clinical examination
- Internal scans using ultrasound, x-ray, CT, EUS, PET or MRI
- Biopsies to test tissue samples
- A bone scan to investigate primary bone sarcomas.
Surgery to remove the tumour is the main form of treatment for most sarcomas. In osteosarcomas, for example, limb sparing surgery, as opposed to amputation, can now be used in at least 90% of cases.
Radiation and chemotherapy also have important roles to play prior to, and after, surgery, or may be the main treatment option. Newer treatments use drugs or man-made versions of antibodies from the immune system to block the growth of cancer cells while leaving normal cells undamaged.
Treatment can be long and hard, lasting about a year for many patients. Young patients also often need ongoing rehabilitation and a range of expensive prostheses throughout their growing years.
About 60% of patients diagnosed with a soft tissue sarcoma are cured by surgery with or without radiotherapy if the cancer has not spread to other parts of the body. Cure rates are much lower once sarcomas have spread to other sites.
The survival rate for bone sarcomas is about 70% if the cancer has not spread and surgery is vital if the cancer is to be cured. However, chemotherapy is used for the most common subtypes of bone sarcomas – Ewing sarcoma and osteosarcoma – and is critical to curing the patient.
One in five sarcoma survivors will develop a second cancer, including a second sarcoma, within 10 years. Radiation therapy itself can be a risk factor for a recurrence. Even though patients are monitored closely the risk of recurrence is a great source of anxiety for patients and their families and is devastating when it happens.
Identifying those at increased risk may lead to early detection, more effective treatment and better survival. This is why Garvan’s Professor David Thomas is searching for new ways to predict who is at increased risk and what individualised therapies and surveillance might offer the best outcomes.