Although relatively rare, sarcomas are devastating cancers that arise in the connective tissues – bone, muscle, tendons, nerves, fat, cartilage and blood vessels – and can occur anywhere in the body. There are more than 50 subtypes of sarcoma, each requiring different treatment and needing highly specialised multidisciplinary care. The two main kinds of sarcoma are soft tissue sarcomas, affecting mainly adults, and bone sarcomas which are much more common in children and young adults.
Sarcoma Risk Factors
In most cases the cause of sarcoma remains unknown. Increased risk includes exposure to radiation and chemical carcinogens – including radiation and chemotherapy for treatment of a previous cancer. But several genetic disorders that run in families can predispose a person to sarcoma. These include Li-Fraumeni syndrome, neurofibromatosis, Gardner syndrome and retinoblastoma. There is also a heightened risk if other family members have had sarcoma or if a person suffers from Paget’s disease.
Surgery to remove the tumour is important in the treatment of most sarcomas. In osteosarcomas, for example, limb sparing surgery, as opposed to amputation, can now be used in at least 90 per cent of cases. Young patients, however, often need ongoing rehabilitation and a range of expensive prostheses throughout their growing years.
Radiation and chemotherapy also have important roles to play prior to and after surgery or may be the main treatment option. Nevertheless, treatment can be long and hard, lasting about a year for many patients. 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.
About 60 per cent 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 per cent 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 along with surgery 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 Prof David Thomas is searching for new ways to predict who is at increased risk and what individualised therapies might offer the best outcomes.
Garvan's research into sarcoma
Garvan’s sarcoma research is diverse. In liposarcomas (sarcomas of fatty tissue), scientists have been investigating a massive mutation called the neochromosome where a chromosome shatters and its remnants rearrange themselves to form a ‘giant’ cancerous mutation. There is ongoing research into how the immune system works in osteosarcomas and how sarcomas develop resistance to drugs.
Prof David Thomas is working to understand why sarcoma happens to some people, and at such a young age. He has created the International Sarcoma Kindred Study (ISKS) to address this important question, with study sites around the world collecting data and samples on 3000 families over the next three years.
This is the largest study of sarcoma risk ever undertaken and a unique resource globally. The second wave of this research, the Surveillance in Multi-Organ Cancer Syndromes+study, is developing and testing approaches to modifying the risk of cancer in families carrying an excess of genetic risk and offers a new generation of cancer risk management.
World First Whole Genome Sequencing of Sarcoma
Garvan recently became one of the first in the world to acquire technology that can sequence a whole human genome at a base cost of around US$1000. This will give Professor Thomas and his team the unprecedented ability to undertake whole genome sequencing on each member of the 3000 families in the ISKS study in order to comprehensively map the genetic basis of developing these rare diseases of the young – leading to better prevention and safer, more effective personalised therapies.