56 Dose escalation in the treatment of lung cancer with CyberKnife without increasing the dose to the organs at risk: a treatment planning study compared to 3-D radiotherapy

AbstractWe report on a comparative dosimetrical study between deep inspiration breath hold (DIBH) and shallow breathing (SB) in prone crawl position for photon and proton radiotherapy of whole breast (WB) and locoregional lymph node regions, including the internal mammary chain (LN_MI). We investigate the dosimetrical effects of DIBH in prone crawl position on organs-at-risk for both photon and proton plans. For each modality, we further estimate the effects of lung and heart doses on the mortality risks of different risk profiles of patients. Thirty-one patients with invasive carcinoma of the left breast and pathologically confirmed positive lymph node status were included in this study. DIBH significantly decreased dose to heart for photon and proton radiotherapy. DIBH also decreased lung doses for photons, while increased lung doses were observed using protons because the retracting heart is displaced by low-density lung tissue. For other organs-at-risk, DIBH resulted in significant dose reductions using photons while minor differences in dose deposition between DIBH and SB were observed using protons. In patients with high risks for cardiac and lung cancer mortality, average thirty-year mortality rates from radiotherapy-related cardiac injury and lung cancer were estimated at 3.12% (photon DIBH), 4.03% (photon SB), 1.80% (proton DIBH) and 1.66% (proton SB). The radiation-related mortality risk could not outweigh the ~ 8% disease-specific survival benefit of WB + LN_MI radiotherapy in any of the assessed treatments.

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P29.03 Thoracic Organs at Risk (OARs) Contouring Variations and Consensus in Radiation Therapy for Non-Small Cell Lung Cancer

Journal of Thoracic Oncology ◽

10.1016/j.jtho.2021.08.398 ◽

2021 ◽

Vol 16 (10) ◽

pp. S1047-S1048

Author(s):

J.L. Liu ◽

X. Jiang ◽

Z. Tan ◽

Z. Li ◽

Y. Wang ◽

...

Keyword(s):

Lung Cancer ◽

At Risk ◽

Radiation Therapy ◽

Small Cell Lung Cancer ◽

Cell Lung Cancer ◽

Organs At Risk ◽

Small Cell ◽

Small Cell Lung

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A Comparative Study of Auto-contouring Softwares in Delineation of Organs at Risk in Lung Cancer and Rectal Cancer

10.21203/rs.3.rs-323597/v1 ◽

2021 ◽

Author(s):

weijun chen ◽

Cheng Wang ◽

Wenming Zhan ◽

Yongshi Jia ◽

Fangfang Ruan ◽

...

Keyword(s):

Lung Cancer ◽

At Risk ◽

Rectal Cancer ◽

Organs At Risk ◽

Similarity Index ◽

Slight Modification ◽

Ct Images ◽

Target Area ◽

Ct Image ◽

Significant Difference

Abstract Background:Radiotherapy requires the target area and the organs at risk to be contoured on the CT image of the patient. During the process of organs-at-Risk (OAR) of the chest and abdomen, the doctor needs to contour at each CT image. The delineations of large and varied shapes are time-consuming and laborious.This study aims to evaluate the results of two automatic contouring software on OAR definition of CT images of lung cancer and rectal cancer patients. Methods: The CT images of 15 patients with rectal cancer and 15 patients with lung cancer were selected separately, and the organs at risk were outlined by the same experienced doctor as references, and then the same datasets were automatically contoured based on AiContour®© (Manufactured by Linking MED, China) and Raystation®© (Manufactured by Raysearch, Sweden) respectively. Overlap index (OI), Dice similarity index (DSC) and Volume difference (DV) were evaluated based on the auto-contours, and independent-sample t-test analysis is applied to the results. Results: The results of AiContour®© on OI and DSC were better than that of Raystation®© with statistical difference. There was no significant difference in DV between the results of two software. Conclusions: With AiContour®©, auto-contouring results of most organs in the chest and abdomen are good, and with slight modification, it can meet the clinical requirements for planning. With Raystation®©, auto-contouring results in most OAR is not as good as AiContour®©, and only the auto-contouring results of some organs can be used clinically after modification.

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