Explaining sarcomas and the treatment option of radiation

Dr Nirasha Chiranjan, a radiation oncologist, educates us on the different types of sarcomas and the treatment option of radiation for soft tissue sarcomas.

Types of sarcomas 

There are a wide range of sarcomas that form in the body; some are benign whilst others are malignant. 

Sarcomas can form: from blood cells; in the cells around joints or tendons; in cartilage, bone, fibrous tissue, skin, mouth, internal organs, in connective tissue and in soft tissue. 

Determining your treatment pathway

The type of sarcoma a patient is diagnosed with will determine the type of specialist team and treatment approach the patient requires.

Soft tissue sarcomas develop in supporting or connective tissue, such as the muscle, nerves, tendons, blood vessels and fatty and fibrous tissues. They are rare malignant tumours that arise from soft tissues at any body site. 

Due to the rarity of this disease, patients with soft tissue sarcoma should be managed by a multi-disciplinary team made up of oncologists, surgeons, pathologists, radiologists and allied health workers to ensure best care and rehabilitation.

Is it a common cancer and how would I know I have a sarcoma?

Sarcomas are not common and they make up a small percentage of all newly diagnosed cancers. Certain sarcomas are more common in children then adults.

Soft tissue sarcomas represent less than 1% of all newly diagnosed malignant tumours¹.They are most commonly found in the limbs (arms and legs), torso (chest, back and abdomen) and pelvis.²

The most common presenting complaint for a soft tissue sarcoma is a gradually enlarging, painless mass. These tumours can become quite large, especially in the thigh and pelvis. Some patients complain of pain or symptoms associated with compression by the mass, including loss of sensation, blockage of bowel or swelling of a limb. 

If you notice a painless mass, you should see your healthcare practitioner for proper assessment. Rarely, a patient may present with constitutional symptoms, such as fever and weight loss.

How are sarcomas diagnosed?

A medical history and examination is done by your healthcare practitioner. This is then followed by imaging tests, like an MRI, CT or PET CT scan, to determine if the mass is suspicious for sarcoma, and if it has spread to nearby local structures or distant organs, like the lungs. 

Patients with soft tissue masses that are suspicious for sarcoma should be referred to centres that specialise in the management of sarcomas so that the proper pathological diagnosis can be made.

Treatment options for soft tissue sarcoma

Before the introduction of radiotherapy for extremity soft tissue sarcoma, amputation was the standard of care which resulted in significant physical and psychological morbidity. 

In treating extremity soft tissue sarcomas, the major therapeutic goals are survival, avoidance of a local recurrence, maximising function, and minimising morbidity.³

Limb-sparing surgical resection and radiation are recommended for most patients with soft tissue sarcomas of the extremities or chest wall. The addition of radiation minimises the risk of recurrence and maximises body function and long-term survival.

Radiotherapy is used to effectively eradicate disease at a cellular level and can be offered before or after surgery. There is no difference in local control between pre-operative radiotherapy and post-operative radiotherapy. 

Pre-operative radiotherapy allows for a reduction in the tumour size and more conservative surgery. A lower radiation dose is administered to a smaller target volume. It is, however, associated with more wound healing problems following surgery. 

Radiotherapy for soft tissue sarcomas is generally very well-tolerated with most side effects occurring in the area the radiotherapy is delivered. Long-term side effects are uncommon and can include scarring of the soft tissues, joint stiffness and swelling.⁴

A variety of radiotherapy techniques can be employed to improve disease control and functional outcomes. 

Modern radiotherapy machines and advanced treatment planning techniques, like intensity-modulated radiation therapy (IMRT) and stereotactic radiotherapy, have been shown to reduce side effects in the pre-operative and post-operative radiotherapy setting.^5,6 

In the metastatic setting, palliative radiotherapy can be used for pain control and symptom relief.

In conclusion, radiotherapy plays an important role in the multi-modality treatment of patients with soft tissue sarcomas and yields positive physical and emotional benefits when working within a multi-disciplinary approach.

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