Soft tissue tumours can occur anywhere in the mesenchymal tissues; this includes muscle, fat, blood vessels, nerves and other supporting tissue.
Facts and figures about soft tissue sarcomas
Soft tissue sarcomas are rare, around 3,270 new cases a year in the UK, accounting for approximately 1% of all new cancer cases. They can occur at any age but approximately 66% are diagnosed in those over 50 years of age, although 9% are diagnosed in those less than 30 years.
There are numerous different tumours types that are classified as soft tissue sarcomas and there are some differences in factors such as age group, where the tumours commonly arise etc. Incidence is approximately the same in both sexes.
Risk factors include some genetic conditions such as neurofibromatosis and Li-Fraumen syndrome, previous radiotherapy to the area and occupational exposure to chemical used in the production of PVC and weedkillers. Many of these tumours have a high incidence of recurrence.
- Fibrosarcoma: Most common sites are arms, legs or trunk, mostly occurring in those between the age of 20 and 60 years.
- Liposarcoma: Occur in subcutaneous fat and retroperitoneal tissues, mostly occurring in those aged 50-65 years of age.
- Rhabdomyosarcoma: Embryonal - most common sites are head, neck and orbit, occurring in children and young adults.
- Rhabdomyosarcoma: Alveolar - most commonly presenting in the trunk, occurring in adolescents and young adults.
- Leiomyosarcoma: Most common site is uterus but also other sites such as stomach, bowel and retroperitoneum. One of the most common sarcomas, highest incidence is in the elderly.
- Synovial sarcoma: Arise in the joints, bursae and tendon sheaths particularly in the hands, feet and knees of young adults.
- Angiosarcomas: (Tumour within the lining of the blood vessels) usually arise in the skin, subcutaneous tissue and glandular sites such as breast and thyroid and sometimes the liver.
- Lymphangiosarcoma: Rare form of angiosarcoma linked to areas of chronic lymphoedema.
- Haemangiopericytoma: Arise in the walls of the blood capillaries and most commonly occur in the limbs and retroperitoneal spaces and sometimes in the head and neck.
- Kaposi’s sarcoma: These usually present as slow growing pigmented skin lesions and those of Jewish, Italian and West African origin have an increased risk of developing this. As well as in the skin, it can occur in the mouth and internal organs such as the lungs, liver and spleen. However, in recent times it is now linked to a weakened immune system and is common in those who are HIV+ or have AIDS. 80% of cases of Kaposi’s sarcoma are now HIV positive.
- Alveolar soft part sarcoma: Most commonly arise in the extremities, particularly the thigh of young adults, usually females but may arise in the head and neck of children.
- Gastrointestinal stromal tumours (GIST): Arise in the gastrointestinal tract, approximately 70% in the stomach, 20% in the small intestines and 10% in the oesophagus. Most occur in those aged between 50 and 70 years of age.
- Malignant peripheral nerve sheath tumours (MPNST): Arises in the soft tissues that surround nerves, common sites are sciatic nerve, brachial plexus and sacral plexus. Most occur in those between 20 and 50 years of age. Approximately 50% of cases are diagnosed in patients with neurofibromatosis.
Soft tissue sarcomas symptoms
Some sarcomas do not cause symptoms for some considerable time and they will depend on where the tumour has developed.
Diagnosis of soft tissue sarcomas
Investigations will depend on location of the tumour but may include:
- Physical examination.
- Blood tests.
- Chest X-rays.
- CT scan.
- PET scan.
- MRI scan.
- Ultrasound scan.
Soft tissue sarcomas treatment
Depends on several factors:
- The type of sarcoma.
- The position of the sarcoma.
- The stage of the cancer.
- Age and general health.
Surgery will often be the main treatment. The extent will depend on the position and size of the sarcoma. The intention will usually be to remove the tumour and some surrounding healthy tissue; this will often be a wide local excision (WLE).
In cases where the tumour is in a limb, surgeons will perform limb sparing surgery if possible and only amputate if this is not feasible. Radiotherapy and/or chemotherapy may be advised post-operatively.
Radiotherapy is important in the treatment of soft tissue sarcomas and is usually given post-operatively (adjuvant) particularly in limb tumours to reduce the risk of recurrence.
Developments in radiotherapy such as Intensity Modulated Radiotherapy (IMRT) has been proven to increase the effectiveness of treatment by enabling the disease to be targeted very accurately hence reducing dose to healthy tissue and reducing side effects, this is particularly useful in treating sarcomas in sites such as the retroperitoneum to enable critical organs such as the spinal cord to be avoided.
Image Guided Radiotherapy (IGRT) also enables the radiotherapy to be precisely delivered to the intended area which reduces potential radiation dose to healthy tissues.
Wide local excision with radical radiotherapy are satisfactory methods of control in a large number of cases. Radiotherapy is also given pre-operatively sometimes (neoadjuvant) to shrink the tumour and help improve removing the tumour, which in some cases may enable amputation to be avoided.
Chemotherapy is sometimes given pre-operatively (neoadjuvant) to help shrink the tumour and help make surgical removal easier. Also, may be given post-operatively (adjuvant) to reduce the risk of recurrence and in some cases of advanced disease it may be used to help control symptoms.
Chemotherapy drugs commonly used are ifosfamide and doxorubicin, others include gemcitabine and docetaxel.
Trials are evaluating the use of cancer growth inhibitors and monoclonal antibodies to treat soft tissue sarcomas. These drugs include imatinib, sunitinib and pazopanib.