When Should We Use Proton Beams to Treat Multiple Lung Lesions: An NTCP Model-Based Decision-Making Strategy

Document Type

Conference Proceeding

Publication Date

6-2024

Publication Title

International Journal of Particle Therapy

Abstract

Background and aims: Although proton based radiotherapy such as IMPT display encouraging dosimetric advantages in treating multiple lung lesions, a much higher cost compared with photon based radiotherapy raises a pivotal question concerning clinical economics. The aim of this study is to compare the dosimetric differences in VMAT and IMPT SBRT of multiple lung lesions and determine a NTCP model-based decision strategy that determines which treatment modality the patient will use. Methods: A total of 41 patients were retrospectively selected for this study. The number of patients with 1-6 lesions was 5, 16, 7, 6, 3 and 4, respectively. SBRT plans were generated using VMAT and IMPT. The IMPT plans used robust optimization parameters of ± 3.5% range and 5-mm setup uncertainties. Dosimetric metrics and the predicted NTCP value of radiation pneumonitis (RP), esophagitis, and pericarditis were analyzed to evaluate the potential clinical benefits between different planning groups. In addition, a threshold for the number of lesions and the ratio of PTV to lungs (%) to determine whether a patient would benefit highly from IMPT was determined using receiver operating characteristic curves. Results: All plans reached target coverage (V70Gy ≥ 95%). Compared with VMAT, IMPT resulted in a significantly lower dose of most thoracic normal tissues. For the 1-2, 3-4 and 5-6 lesion groups, the lung V5 was 29.90 ± 9.44%, 58.33 ± 13.35%, and 81.02 ± 5.91% for VMAT and 11.34 ± 3.11% (P <0.001), 21.45 ± 3.80% (P <0.001), and 32.48 ± 4.90% (P <0.001) for IMPT, respectively. In the VMAT group, the maximum NTCP value of radiation pneumonitis was 73.91%, whereas it was significantly lower in the IMPT group at 10.73%. The accuracy of our NTCP model-based decision model, which combines the number of lesions and PTV/Lungs (%), was 97.6%. Conclusions: The study demonstrated that the IMPT SBRT strategy for multiple lung lesions had a good safety profile, even when the number of lesions reached six. The NTCP model-based decision strategy presented in our study could serve as an effective tool in clinical practice, aiding in the selection of the optimal treatment modality between VMAT and IMPT.

Volume

12

Issue

Suppl

First Page

5

Comments

62nd Annual Conference of the Particle Therapy Cooperative Group (PTCOG), June 10-15, 2024, Singapore

DOI

10.1016/j.ijpt.2024.100122

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