Safety and Local Control of Radiation Therapy for Chordoma of the Spine and Sacrum

Abstract

Study Design Systematic literature review. Objective To assess the toxicity, common radiation doses, and local control (LC) rates of radiation therapy for chordoma of the spine and sacrum and identify the difference in LC and toxicity between adjuvant, salvage, and primary therapy using radiation. Summary of Background Data Chordoma of the spine is typically a low-grade malignant tumor thought to be relatively radioresistant with a high rate of local recurrence and the potential for metastases. Improved results of modern radiation therapy in the treatment of chordoma support exploration of its role in the management of primary/de novo chordoma or recurrent chordoma. Methods We conducted a systematic literature review using PubMed and Embase databases to assess information available regarding the toxicity, LC rates, and overall survival (OS) rates for adjuvant, salvage, and primary radiation therapy for spinal and sacral chordoma. Results A total of 40 articles were reviewed. Evidence quality was low or very low. The highest rates of LC and OS were with early adjuvant RT for primary/de novo disease. Salvage RT for recurrent disease has very small cohorts and thus strong conclusions were not able be made. Conclusion The use of pre- and/or post-operative photon image-guided radiotherapy (IGRT), proton or carbon ion therapy should be considered for patients undergoing surgery for the treatment of primary and recurrent chordomas in the mobile spine and sacrum, since these RT modalities may improve local control. Preoperative evaluation by the surgeon and radiation oncologist should be used to formulate a cohesive treatment plan. The use of photon IGRT or carbon ion therapy as the primary treatment of chordoma, when currently in its developmental stage, shows promise and requires clear delineation of toxicity profile and long-term local control.

Role of the Apparent Diffusion Coefficient as a Predictor of Tumor Progression in Patients with Chordoma

“…The role of RT might be underestimated because high-dose RT is needed to reduce the risk of recurrence and improve patient prognoses. 12,13,37 Further studies are needed to address these issues.…”

“…It is important to recognize recurrence early to ensure adequate salvage therapy. 6,13 Although radiologic evaluation is important in oncology, assessment of tumor progression or response to treatment is based on changes in the residual tumor size on imaging. 14 ADC can identify further characteristics of many tumors with malignant potential.…”

A prospective clinical trial of proton therapy for chordoma and chondrosarcoma: Feasibility assessment

“…Chordomas and chondrosarcomas are rare malignant tumors that typically occur at the base of skull or sacrum. The standard treatment for these tumors is surgical resection with or without adjuvant radiation therapy (RT), typically to doses > 70 Gy . Most treatment failures are local, and salvage is often unsuccessful .…”

“…The standard treatment for these tumors is surgical resection with or without adjuvant radiation therapy (RT), typically to doses > 70 Gy. 1 Most treatment failures are local, and salvage is often unsuccessful. 2 Proton therapy (PRT) has emerged as a potentially favorable option for these lesions because of its rapid dose-fall off which allows for dose escalation to the tumor while minimizing dose to the organs-at-risk (OARs).…”

Spinal stereotactic body radiotherapy following intralesional curettage with separation surgery for initial or salvage chordoma treatment

“…61 Photon therapy has advantages compared with particle radiation in that it is more accessible, and spinal hardware does not diminish photon therapy efficacy while hardware does affect the efficacy of par- ticle therapy. 46 In this series we present effective control of chordoma without the use of en bloc resection with wide margins, but with curettage, intralesional resection or separation surgery followed by high-dose conformal radiation therapy. As seen in the two case examples, tumor volume decreases following intralesional surgery and high-dose SBRT as evidenced by the change in ESCC score.…”