RT is classified as preoperative, definitive (without surgery) or adjuvant – postoperative.
When evaluating the benefits of RT, it is useful to distinguish sarcomas according to their location. The basic treatment method for retroperitoneal and pelvic sarcomas is resection. A more aggressive, extensive en-bloc resection involving adjacent organs has shown to reduce the risk of local relapse. Postoperative RT has shown to significantly prolong time before recurrence in several studies. However, survival time is not extended. The clear indication for RT is in cases where resection cannot be considered radical (R1, R2) and where preoperative RT was not applied at the same time. RT, both preoperative and postoperative, can compensate for the insufficient radicality of the surgical procedure. R0 resection is always a priority. The possibilities of RT in retroperitoneal sarcomas are limited by the presence of high-risk organs, kidneys and especially the small intestine in the target volume.
Favorable dosimetric data are demonstrated by studies for particle RT – proton radiotherapy (PRT) and carbon ion radiation therapy (CIRT). Compared to IMRT techniques, the lowest doses are achieved in all high-risk organs, especially the intestines and kidneys.
Preoperative external RT has a higher efficiency than postoperative RT in the parameter of local recurrence risk in retroperitoneal sites. In the treatment of Ewing’s sarcoma, RT is an integral part of treatment protocols and is connected to systemic CHT. RT has an irreplaceable role in the treatment of chondrosarcoma and chordoma. The position of RT supports the difficult attainment of radical surgery (especially with frequent primary localization in the cranial base area) and, at the same time, minimal effectiveness of systemic therapy. However, to achieve an effect on these tumors, classified as “radioresistant”, high doses of radiation (above 70 Gy) must be applied.
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