A sarcoma is a type of cancer that starts in connective tissues, which are the structures in the body that support, protect, and hold other tissues together. Connective tissues include bones, muscles, fat, blood vessels, and nerves. Sarcomas can develop almost anywhere, but they most commonly occur in the arms, legs, and abdomen. Sarcomas are different from other cancers, such as carcinomas, which usually start in organs or tissues lining the body.
Sarcomas are malignant (cancerous) tumours, meaning they can grow and potentially spread to other parts of the body. This is different from benign (noncancerous) tumours, which stay in one place and usually do not pose significant health risks. However, with early detection and proper treatment, many sarcomas can be successfully managed or treated.
What are the different types of sarcomas?
Sarcomas are categorized based on the type of tissue or cell from which they originate. There are two main groups: soft tissue sarcomas and bone sarcomas. There’s also a smaller group of rare tumours called undifferentiated round cell tumours, which can affect either soft tissue or bone.
Soft tissue sarcomas
Soft tissue sarcomas originate from tissues like fat, muscle, nerves, and blood vessels. Common types include:
-
Adipocytic (fat) tumours: For example, liposarcoma (such as well-differentiated or pleomorphic liposarcoma).
-
Fibroblastic tumours: Such as myxofibrosarcoma or dermatofibrosarcoma protuberans, arising from connective tissue fibres.
-
Vascular (blood vessel) tumours: Like angiosarcoma, which starts in blood vessel cells.
-
Pericytic (cells around blood vessels) tumours: For example, malignant glomus tumour.
-
Muscle tumours: Including leiomyosarcoma (smooth muscle) and rhabdomyosarcoma (skeletal muscle).
-
Gastrointestinal stromal tumours (GISTs): These start in specialized cells within the digestive tract.
-
Peripheral nerve sheath tumours: Malignant peripheral nerve sheath tumour (MPNST) originates from nerve cells.
-
Tumours of uncertain origin: Including synovial sarcoma, epithelioid sarcoma, and alveolar soft part sarcoma.
Bone sarcomas
Bone sarcomas develop in bone tissue and are classified based on the type of tissue they resemble:
-
Osteosarcoma: Tumours producing new bone tissue.
-
Chondrosarcoma: Tumours producing cartilage.
-
Angiosarcoma of bone: Tumours producing blood vessels within bones.
-
Other rare bone sarcomas: Such as chordoma and undifferentiated pleomorphic sarcoma of bone.
What causes a sarcoma?
The exact cause of sarcomas is usually unknown. However, certain factors can increase a person’s risk:
-
Genetic conditions: Conditions like Li-Fraumeni syndrome or neurofibromatosis increase the risk of sarcomas.
-
Radiation exposure: Previous radiation therapy for other cancers can increase the risk of sarcoma later in life.
-
Exposure to certain chemicals: Some chemicals, like specific herbicides, are linked to increased sarcoma risk.
-
Chronic inflammation: Long-standing inflammation can also slightly increase sarcoma risk.
In most cases, though, sarcomas develop without an identifiable cause.
What types of tests are used to confirm the diagnosis?
Doctors use various tests to diagnose and evaluate sarcomas:
-
Imaging tests: X-rays, CT scans, or MRIs show the tumour’s size, shape, and exact location.
-
Biopsy: The most critical test, involving taking a tissue sample and examining it under a microscope. The biopsy confirms the presence of sarcoma and helps determine its type.
-
Genetic testing: Some sarcomas have unique genetic changes that can be detected through specialized tests. These tests can confirm the diagnosis and sometimes guide targeted treatments.
Doctors may also perform additional tests to determine if the sarcoma has spread to other body areas.
What is the prognosis for a person with sarcoma?
The prognosis, or outlook, for someone diagnosed with sarcoma varies depending on several factors, including the specific type of sarcoma, its size and location, how aggressive it is, and whether it has spread. Early detection usually leads to better outcomes. Common treatments include surgery, radiation therapy, and chemotherapy, and some sarcomas may respond well to newer targeted therapies. Each person’s situation is unique, so discussing your diagnosis and treatment options with your healthcare team is essential to understand your specific prognosis and management plan.