M Ma*, J Dai, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, China, BeijingCN,

• 
  M Ma

PO-GePV-T-420 (Sunday, 7/25/2021)   [Eastern Time (GMT-4)]

Purpose: Radiotherapy plays an important role in the treatment of lung cancer, and both coplanar beam arrangements (CBA) and noncoplanar beam arrangements (NCBA) are adopted in clinic practice. The aim of this study is to answer the ques- tion whether NCBA are dosimetrically superior to CBA.

Methods: Search of publications were performed in PubMed, Web of Science, and the Cochran Library till March 2020. The searching terms were as following: ((non- coplanar) or ("non coplanar") or ("4pi") or ("4π")) AND (("lung cancer") or ("lung tumor") or ("lung carcinoma")) AND ((radiotherapy) or ("radiation therapy")). The included studies and extracted data were manually screened. All forest and funnel plots were carried out with RevMan software, and the Egger’s regression asymmetry tests were conducted with STATA software.

Results: Nine studies were included and evaluated in the meta-analysis and treat- ment plans were designed with both CBA and NCBA. For the planning target vol- umes (PTV), D98%, D2%, the conformity index (CI), and the gradient index (GI) had no statistically significant difference. For organs-at-risk (OAR), V20 of the whole lung and the maximum dose of the spinal cord were significantly reduced in NCBA plans compared with CBA ones. But V10, V5, and mean dose of the whole lung, the maximum dose of the heart, and the maximum dose of the esophagus exhibited no significant difference when the two types of beam arrangements were compared.

Conclusion: After combining multicenter results, NCBA plans have significant advantages in reducing V20 of the whole lung and max dose of spinal cord.

Funding Support, Disclosures, and Conflict of Interest: the National Natural Science Foundation of China (Grant No. 11875320).

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Keywords

Lung, Stereotactic Radiosurgery, Treatment Planning

Taxonomy

TH- External Beam- Photons: treatment planning/virtual clinical studies

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