Radiation is used for both curative treatment and for palliation. It may be used alone or in conjunction with surgery and/or chemotherapy. The radiation oncologist is an integral part of the sarcoma management team that performs a preoperative assessment of patients with possible sarcomas.
Combined with surgery, radiation therapy has
- improved local tumor control and
- frequently allows for less radical and mutilating surgery (for example, limb salvage).
It is essential that there is good communication between the surgeon and radiation oncologist to ensure that these two modalities are combined to their best effect.
- Radiation is indicated for most patients with high grade soft tissue sarcomas after limb sparing surgery or wide local excision
- Patients who may be suitable for surgery alone are those who have tumours which are located superficially, are < 5 cm in size and are widely excised (e.g. underlying fascia removed and at least 1 cm in all other directions)
- Inappropriate drain site placement or surgical exploration of the primary site may seriously compromise radiation therapy delivery.
- Radiation therapy may be given either PRE or POST operatively. Both approaches have their advantages and disadvantages.
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Pre-operative Radiation Therapy |
Post-operative Radiation Therapy |
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Advantages:
- Smaller treatment volume
- Normal blood vessels in situ and so fewer hypoxic (radioresistant) cells present
- Surgery facilitated (fibrosis of reactive zone)
- Avoidance of delays due to operative complications
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Advantages:
- Full pathology report available
- Avoids surgical delay due to complications from radiotherapy
- Biopsy pathology may be inadequate
- Lower risk of wound complications
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Disadvantages:
- higher chance of wound complications
- Post surgical pathology may be more difficult to interpret
- Patient may decide to refuse surgery after radiotherapy completed
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Disadvantages:
* Larger radiation treatment volume required. If there is wide surgical disruption of tissues radiotherapy treatment will be severely compromised. |
Primary, curative radiotherapy may be used alone to ablate local disease:
- where surgical resection is not possible (for example the vertebral column),
- with tumours such as Ewing's sarcoma, which have high local control rates with radiotherapy and chemotherapy without surgery,
- or cases of medical unsuitability for surgery.
Adjuvant radiotherapy combined with wide or radical excision is the best means of achieving local control of disease or most patients. The radiotherapy course is fairly standardized. Doses can be modified depending on the treatment volume and the proximity and nature of surrounding normal structures. Planning may involve computerized tomography and specially made devices for immobilization. A radiotherapy treatment course will usually take 4 to 6.5 weeks and treatment will be given once daily on weekdays.
Early side effects include skin erythema and desquamation (especially in skin creases). Late side effects include fibrosis of subcutaneous tissue and skin atrophy. It is essential that one third of the circumference of a limb be kept out of the radiation field if at all possible. If not, circumferential scarring can occur resulting in an increased risk of subsequent lymphedema and loss of the vascular supply to the limb. Hence the importance of well placed scars.
Palliative Radiotherapy
Radiotherapy can be used to palliate symptoms from incurable sarcoma. It is usually possible to use standard short palliative courses. Sometimes higher doses are required to achieve local control.