TriangleHEALTH PROFESSIONAL · SOURCE READING
Dose and volume
Source: Childhood Soft Tissue Sarcoma Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: April 21, 2025 · Captured 2026-09-09.
Selected source text with whitespace normalised. This Triangle page is not an NCI PDQ summary.
Context: Treatment Option Overview for Childhood Soft Tissue Sarcoma / Radiation Therapy
Radiation volume and dose depend on the patient, tumor, and surgical variables noted above, as well as the following:
Patient age and growth potential.
Ability to avoid critical organs, epiphyseal plates, and lymphatics (but not the neurovascular bundles that are relatively radiation tolerant).
Functional/cosmetic outcome.
Radiation doses are typically 45 Gy to 50 Gy preoperatively, and as high as 60 Gy to very small volumes at highest risk when postoperative resection margins are predicted to be microscopically or grossly positive. Planned brachytherapy is an option if the resection is predicted to be subtotal. This can be accomplished with a simultaneously integrated boost dose (i.e., higher dose area within the larger lower dose volume) or administered with a small field of radiation after the initial volume is treated with a dose of 45 Gy to 50 Gy. However, data documenting the efficacy of a postoperative boost to areas with microscopically positive margins are lacking.[43] The postoperative radiation dose is 55 Gy to 60 Gy for R0 resections, up to 65 Gy for R1 resections (microscopic positive margins), and higher when unresectable gross residual disease exists, depending on overall treatment goals (e.g., definitive local control vs. palliation).
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The COG analyzed local recurrence (LR) for NRSTS after radiation therapy in patients treated in the ARST0332 trial.[3] Patients younger than 30 years with high-grade NRSTS received radiation therapy (55.8 Gy) for an R1, 5 cm or smaller tumor (arm B); radiation therapy (55.8 Gy) with chemotherapy for an R0/R1, larger than 5 cm tumor (arm C); or neoadjuvant radiation therapy (45 Gy) with chemotherapy plus delayed surgery, chemotherapy, and postoperative boost to 10.8 Gy for an R0, smaller than 5 mm margins tumor or R1 tumor, or 19.8 Gy for R2 or unresected tumors (arm D).
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Of 193 eligible patients, 24 had local recurrences (arm B: 1 of 15 [6.7%], arm C: 7 of 65 [10.8%], arm D: 16 of 113 [14.2%]) with a median time to local recurrence of 1.1 years (range, 0.11–5.27 years).
Of 95 patients eligible for delayed surgery after neoadjuvant therapy, 89 (93.7%) achieved R0/R1 margins.
Overall local control after radiation therapy were as follows: R0, 106 of 109 (97%); R1, 51 of 60 (85%); and R2/unresectable, 2 of 6 (33%).
The authors concluded that risk-based treatment for young patients with high-grade NRSTS treated on ARST0332 produced very high local control, particularly after R0 resection (97%), despite lower-than-standard radiation therapy doses.
Radiation margins are typically 2 cm to 4 cm longitudinally and encompass fascial planes axially.[44,45]
Radiation therapy was used in the COG ARST1321 trial.
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