Preoperative Intensity Modulated Radiation Therapy Compared to Three-Dimensional Conformal Radiation Therapy for High-Grade Extremity Sarcomas in Children: Analysis of the Children's Oncology Group Study ARST0332

Avani D. Rao, Qinyu Chen, Lynn Million, Sheri L. Spunt, Thomas J. Fitzgerald, Chen Hu, Sandesh S. Rao, Fran Laurie, Sandy Kessel, Karen Morano, Matthew M. Ladra, Stephanie A. Terezakis

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Purpose: For pediatric patients with large, high-grade, extremity nonrhabdomyosarcoma soft-tissue sarcomas, preoperative radiation therapy (RT) provides the opportunity for smaller radiation fields and tumor shrinkage resulting in less extensive surgery. The potential disadvantage is an increased risk of wound complications after surgery compared with rates after postoperative chemoradiation. We assessed the impact of preoperative RT technique on target coverage in relationship to dose to skin and adjacent joints to determine whether acute wound complications and late musculoskeletal injury might be influenced by treatment technique. Methods and Materials: Of 550 eligible patients <30 years of age, 200 were enrolled in arm D of ARST0332 and received neoadjuvant ifosfamide/doxorubicin, then chemoradiotherapy (45 Gy and ifosfamide) and surgery followed by postoperative RT if gross or microscopic positive surgical margins. One-hundred thirteen patients had extremity nonrhabdomyosarcoma soft-tissue sarcomas, of which 56 patients had preoperative RT plans for digital review. The doses to the target volume, skin (surface to 5 mm depth), adjacent joint, and extremity diameter were analyzed with respect to RT technique. Results: Thirty-eight patients (65%) received 3-dimensional conformal RT (3D-CRT) and 18 (32%) received intensity modulated RT (IMRT). There was no difference in clinical target volume (CTV) size between groups (P =.920); however, IMRT plans had improved CTV coverage to 100% of the prescription dose compared with 3D-CRT plans (median CTV coverage, 92.7% vs 98.6%; P =.011). In patients without target overlap with the skin, IMRT use was associated with reduced percent volume of skin receiving 45 Gy or more (V45Gy) compared with 3D-CRT (median, 1.6% vs 6.3%, respectively; P =.005). IMRT was also associated with reduced V45Gy to the adjacent joint compared with 3D-CRT (median, 1.1% vs 13.2%; P =.018). Conclusions: Preoperative IMRT may improve CTV coverage and reduce the volume of skin and adjacent joint treated to high doses. Future studies should assess whether these dosimetric findings produce differences in clinical and toxicity outcomes.

Original languageEnglish (US)
Pages (from-to)38-44
Number of pages7
JournalInternational Journal of Radiation Oncology Biology Physics
Volume103
Issue number1
DOIs
StatePublished - Jan 1 2019
Externally publishedYes

PubMed: MeSH publication types

  • Journal Article
  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

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