What is a soft tissue sarcoma?
Soft tissue sarcoma is a rare type of cancer that forms as a painless lump usually in the lower or upper limbs. There are over 70 types of soft tissue sarcomas and these are named after the abnormal cells which make up the sarcoma.
The commonest soft tissue sarcoma is the undifferentiated pleomorphic sarcoma which is made up of millions of abnormal spindle shaped cells. Liposarcoma is the next most common type of soft tissue sarcoma that is made up of millions of abnormal fat cells.
Causes of soft tissue sarcoma
The majority of soft tissue sarcomas develop without cause. A rare form of soft tissue sarcoma, neurosarcoma begins in a condition known as neurofibromatosis (Von Reklinghausen’s disease). Here the patient has multiple small soft tissue lumps caused by an abnormal growth and expansion of nerves. Some of these begin as benign lumps but over time turn into sarcomas.
Occasionally, patients who have received radiotherapy to a body part may also develop soft tissue sarcomas in the same region.
An extremely uncommon cause of soft tissue sarcoma is hereditary where an abnormality in a parent’s gene may increase the risk of his/her children developing sarcoma in later life. In this very special condition (Li-Fraumeni syndrome) several relatives or parents of a person may have multiple tumours including bone and soft tissue sarcomas. A person with a history of many cancers should be advised of the possibility that they may carry an abnormal gene that may increase the risk of sarcoma in future generations.
How common is soft tissue sarcoma
Soft tissue sarcoma is a rare condition occurring in approximately 1- 2 people per 100,000 head of population. There is almost an equal risk to males and females.
Soft tissue sarcomas mainly occur in people over the age of 55 years although synovial sarcoma and liposarcoma may occur in patients in their 20s.
Where do soft tissue sarcomas develop?
The most common places where soft tissue sarcomas develop are in the thigh, the shoulder and the pelvis. Occasionally soft tissue sarcomas can also occur in the abdominal cavity and some of these arise from a special type of tumour known as atypical lipomas.
Who is at risk?
Patients with a strong family history of certain cancers and also patients who have received high doses of radiotherapy are at risk.
What are the symptoms?
The most important symptom of soft tissue sarcoma is the presence of a painless mass that has developed over a period of months. Occasionally there is a history of a much smaller softer lump in the same area for some years before increasing in size and changing from soft to firm or hard. Frequently, these lumps are misdiagnosed as lipomas (benign fatty lumps) or haematomas (bruises), and delay in appropriate investigation and diagnosis may occur.
Diagnosis of soft tissue sarcoma
Proper diagnosis of soft tissue sarcoma is made after a series of investigations that eventually lead to a biopsy.
It is imperative that all appropriate tests be performed prior to biopsy. The reason why it is important to have all imaging investigations before biopsy is because the procedure of biopsy may cause disturbances in imaging that may make interpretation of the images difficult.
Biopsy is critical to diagnosis as well as patient outcome. Inappropriate or badly performed biopsy may jeopardise a patient’s chance of successful limb sparing surgery or perhaps even increase the chance of spreading the cancer. This is why it is so important that biopsies should be performed at centres with the expertise to treat sarcomas.
Treatment of soft tissue sarcoma
The main treatment of soft tissue sarcoma is surgery to remove the cancer including a surrounding area of normal tissue around the tumour. There are different types of surgery including limb sparing surgery and amputation.
Limb sparing surgery is where the sarcoma is cut out including part of or the entire soft tissue or neighbouring bone in which it developed, and if present, the gap in the bone is rebuilt using special metal implants or bone grafts from the patient or the bone bank. The soft tissue defect is usually reconstructed using special plastic surgical techniques. These reconstructions allow the patient to have a functioning limb after the surgery, and in over 85% of cases, limb sparing surgery is possible. This type of surgery is combined with a dedicated programme of physiotherapy afterwards to promote a return to normal functioning of the limb. There will always be some weakness, scarring, deformity or limp associated with surgery to the limbs. Poorly performed surgery may jeorpardise a patient’s life or chance for limb sparing surgery by increasing the risk of spread of tumour cells to nearby areas or even as far away as other bones, lungs or body parts. It is important that this complex surgery is performed at centres by teams who are expert in managing sarcoma.
Amputation – Occasionally, it is not possible to cut out a sarcoma and leave the patient with a normally functioning limb. Sometimes it is dangerous to try and save the limb. Under these circumstances, the surgeon has no choice but to amputate the limb. Amputation has a huge affect on limb function so it is important that a carefully planned programme of rehabilitation be undertaken after surgery to maximise a patient’s independence and mobility.
Radiotherapy is an important part of the treatment of soft tissue sarcoma. Soft tissue sarcomas are generally sensitive to radiotherapy and are known to respond to radiotherapy by shrinking in size which may help to make surgery safer, or developing a thick rind around itself as a reaction of the tissue around the tumour to radiotherapy. Radiotherapy is usually given once a day for 5.5 weeks. Before commencement of radiotherapy, the dose of radiotherapy and the different angles of irradiation are calculated by a process called simulation. Here the patient lies on a bed in a special room and the best position for the patient under the radiotherapy beam is calculated and trialled. Later, the patient will be placed in exactly the same position that was decided after the simulation test in order to receive the most effective radiotherapy. Radiotherapy is provided as an outpatient service and patients may continue working or undertaking normal activities until surgery. Although radiotherapy will not make your cancer worse, it is linked with a higher risk of cancer in that area after a long period of time. This risk of a secondary cancer is less than 5%.
Chemotherapy is a programme of drug treatment that patients are given to reduce the risk of spread of the soft tissue sarcoma. This is not commonly given because the overall benefit to patient survival of chemotherapy is disappointingly low. However, if it is prescribed, chemotherapy is usually given to patients through a drip into a main vein in their body before surgery and continued even after the tumour is removed. Chemotherapy can cause the vein it is given into to shrivel up and block off. To reduce the discomfort to patients from multiple stabs that are needed to put drips into them, patients now are treated through a small specialised container (Porta-cath) that is placed under the skin that is temporarily connected to a main vein in their body. The Porta-cath allows chemotherapy to be given safely through the same site regularly. The Porta-cath is permanently removed after completion of chemotherapy or if something has compromised its function such as infection or permanent blockage.
Chemotherapy is given in regular cycles. This means patients under treatment are treated for several days at a time in hospital before being discharged home. The process is repeated again after a few weeks sometimes with the same or additional drugs. It is usual for patients to receive between 3 to 5 cycles before surgery, and for these cycles to be continued after surgery until a total of 10 cycles are given. Each cycle lasts for about 3 weeks. Occasionally, patients do not react well to the harshness of the drugs and the cycles have to be permanently ceased or reduced in intensity. Older patients (usually older than 40 years) do not tolerate chemotherapy well. Sometimes a decision is made to only perform surgery, while other times chemotherapy is given at a lower dose and/or for a shorter time than normal. The tumour is shown to respond by an improvement in symptoms, a reduction in size, or from special tests that are performed after commencement of chemotherapy. Chemotherapy is usually recommended to young patients or very healthy patients who have developed spread of their tumour, usually to the lungs. Sometimes, spread of cancer to the lungs can be treated by surgical removal.
Making decisions about treatment
Before a decision is made to receive treatment, patients should discuss all the options available to them. This information should be provided by the experts in the field and this is best received from centres where specialists group together to provide the best team care that is known as multidisciplinary team treatment.
The reasons for and against treatment should be discussed, as well as why certain combinations and timing of treatment are advisable or not. Patients should expect a clear plan of treatment as well as an understanding of what is required after surgery and with long term follow up visits.
Patients should be confident that those providing their care are experts in the area of bone sarcoma treatment. It is important that each patient exercises their right for multiple opinions if this is what would help them to understand their condition and to decide on the treatment that is required. It is advisable that all patients attend clinic with a carer or friend who will provide necessary support or confirmation of what has been discussed.
Side effects of treatment
Surgery – The side effects of surgery may be classified as early or late. Although uncommon, the early side effects may include pain, nerve injury, vessel injury, fractures, wound healing problems, swelling, paralysis, deep vein thrombosis and pulmonary embolism, infection, heart attacks, bleeding, kidney failure, stroke and death. The late side effects may include scarring, pain, loss of normal function, limp, weakness, limb swelling and infection.
Radiotherapy – The side effects of radiotherapy may include nausea, tiredness, limb soreness, skin irritation, blistering, swelling, pain, pigmentation of the irradiated part, poor healing after surgery, fractures of the adjacent or underlying bone, and anemia. Some of these complications may be bad enough to delay or cease further treatment.
Chemotherapy – The side effects of chemotherapy may include nausea, vomiting, diarrhoea, bleeding, bruising, infection, tiredness, anemia, loss of appetite and weight, heart failure, kidney failure, liver failure, hair loss, nerve injury, vessel injury, loss of sensation in feet and fingers, sensitivity to cold, infertility, development of secondary cancers and death. Some of these complications may be so bad as to require chemotherapy to be delayed, stopped or for doses to be reduced.
SOFT TISSUE SARCOMA SURGERY – MELBOURNE
Professor Peter Choong specialises in soft tissue sarcoma surgery and consults with patients from Melbourne and commonly sees patients from interstate and overseas. He has over 30 years of surgical experience and is a Fellow of the Royal Australasian College of Surgeons. Professor Choong is a distinguished surgical leader who has dedicated his career to improving treatments for musculoskeletal diseases.