Intensity‐modulated radiotherapy versus proton radiotherapy versus carbon ion radiotherapy for spinal bone metastases: a treatment planning study

Abstract

Outcomes for selected patients with spinal metastases may be improved by dose escalation using stereotactic body radiotherapy (SBRT). As target geometry is complex, we compared SBRT plans using step‐and‐shoot intensity‐modulated radiotherapy (IMRT), carbon ion RT, and proton RT. We prepared plans treating cervical, thoracic, and lumbar metastases for three different techniques — IMRT, carbon ion, and proton plans — to deliver a median single 24 Gy fraction such that at least 90% of the planning target volume (PTV) received more than 18 Gy and were compared for PTV coverage, normal organ sparing, and estimated delivery time. PTV coverage did not show significant differences for the techniques, spinal cord dose sparing was lowered with the particle techniques. For the cervical lesion spinal cord maximum dose, dose of 1% (D1), and percent volume receiving 10 Gy (normalV10Gy) were 11.9 Gy, 9.1 Gy, and 0.5% in IMRT. This could be lowered to 4.3 Gy, 2.5 Gy, and 0% in carbon ion planning and to 8.1 Gy, 6.1 Gy, and 0% in proton planning. Regarding the thoracic lesion no difference was found for the spinal cord. For the lumbar lesion maximum dose, D1 and percent volume receiving 5 Gy (normalV5Gy) were 13.4 Gy, 8.9 Gy, and 8.9% for IMRT; 1.8 Gy, 0.7 Gy, and 0% for carbon ions; and 0 Gy,<0.01 Gy, and 0% for protons. Estimated mean treatment times were shorter in particle techniques (6–7 min vs. 12–14 min with IMRT). This planning study indicates that carbon ion and proton RT can deliver high‐quality PTV coverage for complex treatment volumes that surround the spinal cord.PACS number: 87.55.dk

Effect of Carbon Ion Radiation Induces Bystander Effect on Metastasis of A549 Cells and Metabonomic Correlation Analysis

“…In this study, we found that carbon ion radiation changed the metabolite secretion of irradiated cells, thus affecting the biological behavior of unirradiated cells. Generally, X-rays promote migration and invasiveness under normoxic conditions, and carbon ions can significantly reduce migration ( 27 ) and invasion of tumor cells in vitro and vivo ( 23 , 28 ). Further, we used metabonomic analysis to confirm that the culture medium collected from carbon ion irradiated WI-38 cells is related to the decrease of metastatic potential of A549 cells.…”

ROS Production and Distribution: A New Paradigm to Explain the Differential Effects of X-ray and Carbon Ion Irradiation on Cancer Stem Cell Migration and Invasion

“…Several studies have reported that C-ions kill CSCs better than conventional radiotherapy [8,9,10]. Moreover, most of the time, although X-rays promote migration and invasiveness under normoxia [11], C-ions produce a significant benefit by decreasing the migration and invasiveness of cancer cells in vitro [11,12] and in vivo [13,14]. Conversely, a few studies report anti-invasive capacities in response to X-rays, whereas C-ions can be pro-invasive [15].…”

Is proton beam therapy ready for single fraction spine SBRS? – a feasibility study to use spot-scanning proton arc (SPArc) therapy to improve the robustness and dosimetric plan quality

“…Many cancers result in metastasis in the spinal vertebrae, which can cause pain, neurological disability, and reduce quality of life [1,2]. To improve the local disease control and relieve symptoms, radiosurgery could be used for the primary treatment of spinal metastases [3][4][5]. Compared to the standard radiotherapy, Stereotactic body radiosurgery/radiotherapy (SBRS/SBRT) delivers a much higher dose to the tumor in fewer treatment fractions while minimizing the unnecessary dose to the healthy tissues.…”