Development of a Tumor Growth-responsive Robust Planning Method for Head and Neck Cancer in Carbon-ion Radiotherapy.

Autor:	Miyasaka Y; Department of Heavy Particle Medical Science, Yamagata University Graduate School of Medical Science, Yamagata, Japan.; Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, Japan., Kusano Y; Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, Japan; kusano.2270a@kanagawa-pho.jp., Mizoguchi N; Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, Japan., Takayama Y; Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, Japan., Kamada T; Department of Radiation Oncology, Kanagawa Cancer Center, Yokohama, Japan., Iwai T; Department of Heavy Particle Medical Science, Yamagata University Graduate School of Medical Science, Yamagata, Japan., Katoh H; Department of Radiation Oncology, Kanagawa Cancer Center, Yokohama, Japan.
Jazyk:	angličtina
Zdroj:	Anticancer research [Anticancer Res] 2024 Nov; Vol. 44 (11), pp. 5113-5122.
DOI:	10.21873/anticanres.17336
Abstrakt:	Background/aim: The current study aimed to evaluate a treatment planning method that is robust against tumor growth and to assess its effectiveness in particle therapy for head and neck cancer. Patients and Methods: The proposed method optimizes dose distribution by replacing the relative stopping power ratio (rSPR) of the clinical target volume (CTV) cavity region with a tumor-equivalent rSPR (Condition 1). The optimized initial treatment plan template was then recalculated using in-room CT images acquired in the same treatment position, and the doses to the tumor and organs at risk were compared with those in the initial treatment plan. We evaluated this method in 10 patients with head and neck cancer treated with carbon ion radiotherapy. To evaluate the effectiveness of the proposed method, we compared it to the initial treatment plan without the replacement (Condition 2). Results: CTV V95% reduction relative to that of the initial treatment plan at the end of treatment was 1.3%±2.9% and 2.6%±3.7% for Condition 1 and Condition 2, respectively, with Condition 1 (Replacement condition) providing better CTV coverage. Subgroup analysis showed a higher change in target coverage in the mucosal melanoma than in the adenoid cystic carcinoma, suggesting that this was influenced by the rate of tumor growth. Conclusion: The proposed treatment planning method, which adjusts for tumor growth by modifying the rSPR in the cavity region, improved robustness in carbon ion radiotherapy for head and neck cancer. Condition 1 (with replacement) achieved better CTV coverage than Condition 2 (without replacement), particularly in fast-growing tumors like mucosal melanoma. This method ensures consistent dose delivery to tumors while maintaining safe doses to organs at risk, offering potential for improved treatment outcomes. (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)
Databáze:	MEDLINE
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