Radiation Therapy in Adult Soft Tissue Sarcoma—Current Knowledge and Future Directions: A Review and Expert Opinion

Abstract

Radiation therapy (RT) is an integral part of the treatment of adult soft-tissue sarcomas (STS). Although mainly used as perioperative therapy to increase local control in resectable STS with high risk features, it also plays an increasing role in the treatment of non-resectable primary tumors, oligometastatic situations, or for palliation. Modern radiation techniques, like intensity-modulated, image-guided, or stereotactic body RT, as well as special applications like intraoperative RT, brachytherapy, or particle therapy, have widened the therapeutic window allowing either dose escalation with improved efficacy or reduction of side effects with improved functional outcome. This review summarizes the current evidence for RT in adult STS including typical indications, outcomes, side effects, dose and fractionation regimens, and target volume definitions based on tumor localization and risk factors. It covers the different overall treatment approaches including RT either as part of a multimodal treatment strategy or as a sole treatment, namely its use as an adjunct to surgery in resectable STS (perioperative RT), as a primary treatment in non-resectable tumors (definitive RT), as a local treatment modality in oligometastatic disease or as palliative therapy. Due to the known differences in clinical course, general treatment options and, consequently, outcome depending on lesion localization, the main part of perioperative RT is divided into three sections according to body site (extremity/trunk wall, retroperitoneal, and head and neck STS) including the discussion of special applications of radiation techniques specifically amenable to this region. The review of the current evidence is accompanied by a summary on ongoing clinical research pointing at future directions of RT in STS.

Low‐Cost, High‐Pressure‐Synthesized Oxygen‐Entrapping Materials to Improve Treatment of Solid Tumors

“…For studies involving the MPNST‐bearing mice, the tumors were irradiated with 15 gray (Gy) (×1 fraction), 10 Gy (×2 fractions), or 8 Gy (×3 fractions), each of which is equivalent to a biological equivalent dose (BED) used for preoperative treatment of sarcoma tumors in humans, assuming an alpha–beta of 4. [ 11 ] Foam O 2 ‐GeM + radiation (15 Gy) inhibited tumor growth and extended the life span of mice with MPNSTs from a median time of 13 days (no treatment) to 25 days (foam O 2 ‐GeM + radiation) ( Figure A ); treatment at the same BED but different fractionation schemes resulted in outcomes similar to those for the 15 Gy treatment (Figure S11, Supporting Information). The data in Figure 4A,D,E are also represented as the ratio of tumor volume over time to initial tumor volume ( V t / V 0 ) in Figure S12 of the Supporting Information.…”

Similar additive effects of doxorubicin in combination with photon or proton irradiation in soft tissue sarcoma models

“…In clinical practice, the established chemotherapy protocols of X-based radiochemotherapy ( 24 ) are adopted for H-based radiochemotherapy ( 8 ). Unfortunately, there is a lack of large clinical trials investigating the effects of combined H-based radiochemotherapy ( 25 ).…”

The role of radiotherapy in the management of malignant peripheral nerve sheath tumors: a single-center retrospective cohort study

“…The present study carries the intrinsic limitations of retrospective, single-center cohort studies. Within the long study period of 26 years, many new techniques and improvements in the delivery of RT were introduced, which advanced the efficacy and functional outcomes for STS patients (Roeder 2020 ; Alektiar et al 2008 ; Leachman and Galloway 2016 ). Moreover, the imbalances between both groups may introduce bias in detecting and evaluating oncological outcomes.…”