Radiotherapy For Bone Tumors

OSTEOSARCOMA

· Wide local excision (WLE), amputation vs. limb sparing surgery.

· Metastasectomy for pulmonary, visceral metastases improves survival.

· Neoadjuvant chemotherapy for high-grade, localized disease or metastatic disease

· Consider RT for positive margin, subtotal resection, or unresectable tumor

· Consider SBRT for unresectable oligometastatic disease

· Consider Radium-223 or Sm-EDTMP for metastatic disease

· Consider intra-arterial chemo for pelvic tumors

· 5-yr OS for localized disease 60-75%, for metastatic disease 20%

· Follow-up: Exam and imaging q3–6 months (including chest imaging) for 5 years, annually to 10 years

RT doses

· Post-op:R0 55-60 Gy/ R1 64-66 Gy/R2 68-70 Gy

· Unresectable: 60-70 Gy

CHONDROSARCOMA

· WLE is the primary treatment

· RT for inadequate margins, unfavorable location, palliation

· Consider specialized techniques for >70 Gy, like proton beam RT, carbon ions or SBRT if normal tissue sparing is possible)

· 5-yr OS 50–70%

· Follow-up: Exam and imaging q3–6 months (including chest imaging) for 5 years

RT doses

· Post-op: R1 70 Gy / R2 >70 Gy (72-78 Gy)

· Pre-op (consider if positive margins predicted): 42,75 Gy/ 15 fraction or 50 Gy/25 fr

· IORT: 15–30Gy

· Unresectable: >70 Gy using specialized techniques (for low grade unresectable 70 Gy)

CHORDOMA

· WLE or en bloc resection is the primary treatment, followed by RT

· Consider proton or particle beam Preoperative RT may be effective

· RT alone for unresectable disease

· EGFR inhibitors can be added to surgery/RT for recurrent disease

· 5-yr OS 75–80%

· Follow-up: Exam and imaging (including chest) q6 months for 5 years, then annually

RT doses

· Post-op: R1 70 Gy / R2 72-78 Gy

· Unresectable: >70 Gy using specialized techniques like Proton

· SBRT 40 Gy in 5 Fr

· 66–70 Gy standard fractionation

· Proton: 74 Gy

GIANT CELL TUMOR

· Stage I–II: Intralesional curettage

· Stage III: WLE

· RT for unresectable, recurrent, progressive disease or inadequate margins or not responded to other treatments

· Denosumab, interferon, embolisation

· 5-yr OS: 80–100%, formalignant30%

· Exam and imaging q6months x 2 years, annually thereafter

RT doses

· >40 Gy (50-60 Gy)

EWING SARCOMA

· 5-yr OS: Localized disease 60–70% (10–25% local failure after definitive RT), Lung and pleural metastases 30%, Bone and bone marrow metastases 15%, Local treatment without chemotherapy 10%

RT doses

· Definitive RT with no soft-tissue involvement: Pre-Chemo GTV (Gross Tumor Volume) + 2 cm 55.8 Gy.

· Definitive RT with a soft-tissue component: Pre-Chemo GTV + 2 cm  45 Gy, and 55.8 Gy boost to the initial bony GTV + Post-Chemo soft-tissue extent with a minimal margin.

· Post-op RT: within 60 days of surgery, pretreatment GTV + 2 cm  45 Gy, and boost to any postoperative gross residual disease + 2 cm  55.8 Gy.

· For node (+) disease, to the nodal bed 50.4 Gy if resected or 55.8 Gy for gross residual disease.

· Pre-op RT: GTV + 2 cm 36-45 Gy

· Hemithorax RT: 15-20 Gy (1.5 Gy/fr)

· Metastatic disease: 12 Gy for <6 years old, 15 Gy for <14 years old, 18 Gy for >14 years old

RADIATION TECHNIQUES SIMULATION AND FIELD DESIGN FOR BONE TUMORS

Conventionally fractionated photon radiotherapy

· Spare 1.5–2 cm strip of the skin in extremity RT, if possible, to prevent edema.

· Include entire surgical bed + scar + 2 cm margin, if possible.

· Bolus on scar may be considered as indicated.

· CT/MRI data for treatment planning.

· Try to exclude the skin over anterior tibia, if possible, due to poor vascularity.

· Physical therapy instituted as early as possible during treatment to improve functional outcome.

Stereotactic body radiation therapy (SBRT)

· Pre-op: Clinical Target Volume (CTV)to include region of microscopic disease up to 1 cm from Gross Tumor Volume (GTV)

· Post-op: CTV 0–1 cm expansion of GTV/surgical bed based on the extent of resection and location adjacent to critical structures

· PTV: 2–3 mm on CTV with modern immobilization/IGRT

DOSE LIMITATIONS

· >20 Gy can prematurely close epiphysis.

· >40 Gy will ablate bone marrow.

· ≥50 Gy to bone cortex significantly increases risk of fracture.

· 30 Gy Dmax for 5-fraction SBRT to the brainstem or spinal cord.

· Conventionally fractionated RT Dmax spinal cord45–50 Gy; Dmax brainstem 59.4 Gy.

COMPLICATIONS

· Abnormal bone and soft tissue growth and development ,permanent weakening of the affected bone, scoliosis, decreased range of motion due to fibrosis or joint involvement, vascular changes resulting in greater sensitivity to infection, fracture, lymphedema, skin discoloration or telangiectasia, osteoradionecrosis

· Increased risk of secondary cancers (leukemia, sarcomas)

Sources

· Springer International Publishing AG, part of Springer Nature 2018 , Eric K. Hansen and M. Roach III (eds.), Handbook of Evidence-Based Radiation Oncology, https://doi.org/10.1007/978-3-319-62642-0_39

· National Comprehensive Cancer Network. (2025). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®): Bone cancer [v.1.2026], https://www.nccn.org/professionals/physician_gls/pdf/bone.pdf

· Springer Nature Switzerland AG 2022 1. N. Y. Lee et al. (eds.), Target Volume Delineation and Field Setup, Practical Guides in Radiation Oncology, https://doi.org/10.1007/978-3-030-99590-4

· Springer International Publishing AG, part of Springer Nature 2018 , Eric K. Hansen and M. Roach III (eds.), Handbook of Evidence-Based Radiation Oncology, https://doi.org/10.1007/978-3-319-62642-0_39