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Intensity modulated radiation therapy may be preferable in children with extremity nonrhabdomyosarcoma soft-tissue sarcomas

Source: Rao A et al. Intl J Rad Oncology*Biology*Physics; Jan. 2019, 38-44. https://doi.org/10.1016/j.ijrobp.2018.09.005

Key clinical point: Compared to 3-dimensional conformal radiotherapy, intensity modulated radiation therapy was associated with improved target coverage and reduced volume of skin and nearby joint treated to higher doses, warranting further investigation to understand if preoperative radiotherapy technique leads to reduced risks of long-term functional complications such as wounds and musculoskeletal injury in children with high-grade extremity nonrhabdomyosarcoma soft-tissue sarcomas.

Main finding: The 18 patients who received intensity modulated radiotherapy had better clinical target volume coverage to 100% of the prescription dose compared with the 38 patients who received 3-dimensional conformal radiotherapy plans (median clinical target volume coverage, 92.7% vs 98.6%; P = .011). Intensity modulated radiotherapy was also associated with reduced volume of skin receiving 45 Gy or more to the adjacent joint compared with 3-dimensional conformal radiotherapy (median, 1.1% vs 13.2%; P = .018).

Study details: The study evaluated patients who large, high-grade, extremity nonrhabdomyosarcoma soft-tissue sarcomas and were enrolled in the Children's Oncology Group ARST0332 trial where they received neoadjuvant ifosfamide/doxorubicin, then chemoradiotherapy (45 Gy and ifosfamide) and surgery followed by postoperative radiotherapy in the event of positive surgical margins. Of the 113 patients, 56 patients had preoperative radiotherapy plans that were analyzed with respect to radiotherapy technique.

Disclosures: The authors declared having no relevant disclosures.

Source: Rao A et al. Intl J Rad Oncology*Biology*Physics; Jan. 2019, 38-44. https://doi.org/10.1016/j.ijrobp.2018.09.005

Results

Thirty-eight patients (65%) received 3-dimensional conformal RT (3D-CRT) and 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).

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.

Citation:

Rao A et al. Intl J Rad Oncology*Biology*Physics; Jan. 2019, 38-44. https://doi.org/10.1016/j.ijrobp.2018.09.005

This Week's Must Reads

Intensity modulated radiation therapy may be preferable in children with extremity nonrhabdomyosarcoma soft-tissue sarcomas, Source: Rao A et al. Intl J Rad Oncology*Biology*Physics; Jan. 2019, 38-44. https://doi.org/10.1016/j.ijrobp.2018.09.005

Expanded genetic analyses of myxofibrosarcomas may guide precision therapies, Ogura K et al. Nature Communications; 17 July 2018. https://doi.org/10.1038/s41467-018-03891-9

Malignant tenosynovial giant cell tumors appear to originate from synoviocytes, Al-Ibraheemi A et al. Modern Pathology; 11 Sept. 2018. https://doi.org/10.1038/s41379-018-0129-0

Must Reads in Sarcoma

Intensity modulated radiation therapy may be preferable in children with extremity nonrhabdomyosarcoma soft-tissue sarcomas, Source: Rao A et al. Intl J Rad Oncology*Biology*Physics; Jan. 2019, 38-44. https://doi.org/10.1016/j.ijrobp.2018.09.005

Expanded genetic analyses of myxofibrosarcomas may guide precision therapies, Ogura K et al. Nature Communications; 17 July 2018. https://doi.org/10.1038/s41467-018-03891-9

Malignant tenosynovial giant cell tumors appear to originate from synoviocytes, Al-Ibraheemi A et al. Modern Pathology; 11 Sept. 2018. https://doi.org/10.1038/s41379-018-0129-0