Treating Soft Tissue Sarcoma in Limbs

What is a soft tissue sarcoma?

Soft tissue sarcomas are a group of malignant tumours that can affect children and adults, growing in the soft tissues of the body. It is a relatively rare form of malignant tumour, affecting only 2 – 3 persons per 100,000 per year.

Soft tissue sarcomas can grow in the muscles, the deep layers of the skin, in fat, in blood vessels, nerves and other connective tissues. While they can appear anywhere in the body, most start in the arms and legs. This article will focus on treatment for soft tissue sarcomas in the arms and legs.

Symptoms of soft tissue sarcoma

Soft tissue sarcoma is a relatively rare disease and most visible lumps are not sarcoma, but rather a harmless (benign) cluster of fat cells called a lipoma.

A soft tissue sarcoma appears as a painless lump that grows over time and may not be noticeable until it presses on muscles or nerves. See your doctor if you have a lump that is growing or causes pain.

What causes soft tissue sarcoma?

The cause of soft tissue sarcoma is not fully understood, but the risks are higher in the following circumstances:

• A family history of certain diseases, including neurofibromatosis and Gardner syndrome, which are disorders that make tumours grow in various parts of your body.
• Exposure to certain chemicals like arsenic, vinyl chloride, or dioxin.
• Exposure to radiation, including during treatment for other kinds of malignancies. Soft tissue sarcoma can develop many years after treatment, typically 10 – 20 years post-radiation exposure.

How is soft tissue sarcoma diagnosed?

If your doctor suspects that you might have a soft tissue sarcoma, you will most likely undergo an imaging procedure so your doctor can see inside your body to see if the sarcoma has spread. You will also likely undergo a biopsy procedure, where a sample of the lump is removed to test in the laboratory for an accurate histological diagnosis.

Imaging

Your doctor will order an MRI scan for sarcomas suspected in the arms and legs. This takes detailed images inside your limbs. In some instances, your doctor may also request for an intravenous gadolinium contrast injection to be administered at the time of your MRI scan to help provide more information about the tumour.

Biopsy

A biopsy can be done in one of 2 ways:

• Percutaneous core needle biopsy: Your doctor will insert a needle into the lump via a small (2 – 3mm) skin puncture to retrieve a sample of the cells for analysis. If the lump is in a hard-to-reach place, such as deep in your thigh, your doctor may use a CT or ultrasound scan to help guide the biopsy needle placement. You won't feel any pain during the procedure as the area will be numbed by local anaesthesia.
• Open biopsy surgery: This is done under general anaesthesia, as your surgeon will remove a relatively large sample, or sometimes even the entire tumour specimen (this is known as an excision biopsy), taking care not to disrupt the potential tumour so as to avoid causing any malignant cells present to spread.

How is soft tissue sarcoma in the arm or leg treated?

There are various treatment options available. However, the recommended choice of treatment advocated by your doctor will depend very much on the histological diagnosis, size, location, grade and stage of the soft tissue sarcoma.

Amputation

While a rare procedure, if the cancer is inoperable, there may be no other option than to remove the limb to save one's life.

Limb Salvage Surgery

Your doctor's goal will always be to save and salvage your limb whenever possible, as well as to optimise function via either repair or reconstruction of removed soft tissues using grafts from yourself (autografts), a cadaveric donor (allografts), or even by using tissue regeneration techniques, if available.

In order to ensure that no cancer cells are left behind, your surgeon will usually remove the sarcoma as a single piece (en-mass resection), together with a cuff of normal tissue around the tumour for a margin of safety (wide resection). This gives a far reduced chance of the tumour coming back (lower local recurrence risk). This removed tissue will then be analysed in the laboratory using microscopy, immuno-stains and cytogenetic tests to confirm the histological sub-type, as well as to ensure that no tumour cells are evident around the edges of the removed tissue specimen (negative surgical margins).

If the edges of the tissue are clear (negative surgical margins), you may require no further treatment. However, if cancer cells are found around the edges, it is possible that cancer cells may have been left behind at the surgery site, so your doctor will recommend radiation therapy to kill the remaining cells or further surgery.

What can I expect when undergoing limb salvage surgery?

The surgery is performed in 2 stages under general anaesthesia. In the first stage, your surgeon will first remove the tumour, together with a margin of healthy tissue (en-mass, wide resection). This is followed by the second stage which focuses on reconstructive surgery, with the aim of optimisation of limb function. If bone or joint had been concurrently removed, then a prosthesis or bone graft will be inserted to replace the missing bone or joint. Finally, your surgeon will use healthy soft tissue from your body to close the wound. Depending on the histological diagnosis and surgical margins, you may need to undergo a course of radiation therapy and/or chemotherapy post-operatively.

Are there other risks associated with limb salvage surgery?

As with any surgery, there are peri-operative risks. Specific to limb salvage surgery, in addition to the slight risk that the surgery may fail, you may experience:

• Severe blood loss and anaemia
• Infection of the surgical site
• Loosening or breakage of the implant or bone graft
• Neuromuscular deficits, for eg. numbness or muscle weakness

How long will it take to recover?

You can expect to stay in hospital for up to 7 days as your doctor monitors your post-operative recovery. You will also be started on physical therapy and mobilisation as part of your functional rehabilitation.

It usually takes about 3 weeks for the surgical wound to heal. If your lower limb bone is involved, then you will need to be on non-weight bearing ambulation with mobility aids such as crutches or a walking frame for 6 weeks.

You are also likely to have to undergo physical rehabilitation therapy on an out-patient basis for at least 2 months so that you can regain freedom of movement and function of the limb.

Chemotherapy

If it is found that the tumour cells have already spread to other parts of your body, your doctor will recommend chemotherapy.

Radiation therapy

You may be recommended radiation therapy for several reasons. This may be done before surgery, to shrink the tumour if it is large. If you are too weak for surgery or the tumour is too hard to take out via surgery, radiation may be recommended to kill the cancer cells instead. You may also be given radiation therapy after surgery to kill any potentially remaining cancer cells as a precaution.

Are there side effects?

Chemotherapy and radiation therapy do have side effects. The sides effects can vary, especially with the individual types of chemotherapy administered. Some common chemotherapy side effects include temporary hair loss, nausea, loss of appetite and ulcers in your mouth. On the other hand, with radiation, your skin may experience redness, peeling or blistering.

For a faster recovery, try to eat a healthy diet and rest as much as you can. The treatment may make you weak, so ask your doctor to recommend exercises that may help strengthen you and keep a positive spirit. Many of the side effects are temporary and will resolve once the chemotherapy treatment is completed.

Can soft tissue sarcoma recur?

Even after successful treatment, there is always the risk that soft tissue sarcoma can return, either in the same place (local recurrence) or elsewhere in the body (metastasis). Your doctor will advise you on the signs to watch out for, so that if it does recur, treatment can begin as early as possible. In addition, your doctor may arrange for regular follow-up scans to exclude any recurrence or metastasis.