Soft tissue sarcoma

Soft tissue sarcoma is a broad term for cancers that start in soft tissues (muscle, tendons, fat, lymph and blood vessels, and nerves). These cancers can develop anywhere in the body but are found mostly in the arms, legs, chest, and abdomen. Soft tissue sarcoma is a form of cancer that occurs due to abnormal and uncontrolled cell growth of the "soft tissues" of the body. These tissues connect, support and surround other body parts and may include muscle, fat, blood vessels, lymph vessels, nerves, tendons and the lining of joints.

Types

Table 1: Major Types of Soft-Tissue Sarcomas in Adults

Tissue of Origin	Type of Cancer	Usual Location in the Body
Fibrous tissue	Fibrosarcoma	Arms, legs, trunk
	Malignant fibrous hystiocytoma	Legs
	Dermatofibrosarcoma	Trunk
Fat	Liposarcoma	Arms, legs, trunk
Muscle Striated muscle Smooth muscle	Rhabdomyosarcoma Leiomyosarcoma	Arms, legs Uterus, digestive tract
Blood vessels	Hemangiosarcoma	Arms, legs, trunk
	Kaposi's sarcoma	Legs, trunk
Lymph vessels	Lymphangiosarcoma	Arms
Synovial tissue (linings of joint cavities, tendon sheaths)	Synovial sarcoma	Legs
Peripheral nerves	Malignant peripheral nerve sheath tumour/Neurofibrosarcoma	Arms, legs, trunk
Cartilage and bone-forming tissue	Extraskeletal chondrosarcoma	Legs
	Extraskeletal osteosarcoma	Legs, trunk (not involving the bone)

Table 2: Major Types of Soft-Tissue Sarcomas in Children

Tissue of Origin	Type of Cancer	Usual Location in the Body	Most common ages
Muscle
Striated muscle	Rhabdomyosarcoma
	Embryonal	Head and neck, genitourinary tract	Infant–4
	Alveolar soft part sarcoma	Arms, legs, head, and neck	Infant–19
Smooth muscle	Leiomyosarcoma	Trunk	15–19
Fibrous tissue	Fibrosarcoma	Arms and legs	15–19
	Malignant fibrous histiocytoma	Legs	15–19
	Dermatofibrosarcoma	Trunk	15–19
Fat	Liposarcoma	Arms and Legs	15–19
Blood vessels	Infantile hemangio-pericytoma	Arms, legs, trunk, head, and neck	Infant–4
Synovial tissue (linings of joint cavities, tendon sheaths)	Synovial sarcoma	Legs, arms, and trunk	15–19
Peripheral nerves	Malignant peripheral nerve sheath tumors (also called neurofibrosarcomas, malignant schwannomas, and neurogenic sarcomas)	Arms, legs, and trunk	15–19
Muscular nerves	Alveolar soft part sarcoma	Arms and legs	Infant–19
Cartilage and bone-forming tissue	Extraskeletal myxoid chondrosarcoma	Legs	10–14
	Extraskeletal mesenchymal	Legs	10–14

Cause

No one knows exactly what causes these cancers.

Riskfactors

People who have previously received radiation therapy and those with certain inherited disorders (such as Gorlin syndrome, Gardner syndrome, Li-Fraumeni syndrome, Tuberous sclerosis, neurofibromatosis type 1, and Werner syndrome) have an increased risk of developing a soft tissue sarcoma.

Signs and symptoms

A sarcoma may appear as a painless lump under the skin, often on an arm or a leg. Sarcomas that begin in the abdomen may not cause signs or symptoms until they get very big. As the sarcoma grows bigger and presses on nearby organs, nerves, muscles, or blood vessels, signs and symptoms may include:

• Pain.
• Trouble breathing.

Diagnosis

The only reliable way to determine whether a soft-tissue tumour is benign or malignant is through a biopsy. The two methods for acquisition of tumour tissue for cytopathological analysis are:

• Needle aspiration biopsy, via needle
• Surgically, via an incision made into the tumour

A pathologist examines the tissue under a microscope. If cancer is present, the pathologist can usually determine the type of cancer and its grade. Here, 'grade' refers to a scale used to represent concisely the predicted growth rate of the tumour and its tendency to spread, and this is determined by the degree to which the cancer cells appear abnormal when examined under a microscope. Low-grade sarcomas, although cancerous, are defined as those that are less likely to metastasise. High-grade sarcomas are defined as those more likely to spread to other parts of the body. For soft-tissue sarcoma, the two histological grading systems are the National Cancer Institute system and the French Federation of Cancer Centers Sarcoma Group system.

Treatment

The best treatment options depend on many factors but may include surgery, chemotherapy, and radiation therapy. The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Olaratumab (Brand name: Lartruvo)In combination with doxorubicin, for the treatment of adult patients with soft tissue sarcoma (STS) with a histologic subtype for which an anthracycline-containing regimen is appropriate and which is not amenable to curative treatment with radiotherapy or surgery.
• Pazopanib (Brand name: Votrient)Advanced soft tissue sarcoma (STS) who have received prior chemotherapy.

Epidemiology

Soft-tissue sarcomas are relatively uncommon cancers. They account for less than 1% of all new cancer cases each year. This may be because cells in soft tissue, in contrast to tissues that more commonly give rise to malignancies, are not continuously dividing cells.

In 2006, about 9,500 new cases were diagnosed in the United States.Soft-tissue sarcomas are more commonly found in older patients (>50 years old), although in children and adolescents under age 20, certain histologies are common (rhabdomyosarcoma, synovial sarcoma).

Around 3,300 people were diagnosed with soft-tissue sarcoma in the UK in 2011.

NIH genetic and rare disease info

• NIH info on Soft tissue sarcoma

Soft tissue sarcoma is a rare disease.

Soft tissue sarcoma Resources
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