Low Dose-Averaged LET Contributes to Local Recurrence of Pancreatic Cancer Treated with Carbon Ion Radiotherapy.

IF 6.4 1区医学 Q1 ONCOLOGY

International Journal of Radiation Oncology Biology Physics Pub Date : 2025-07-16 DOI:10.1016/j.ijrobp.2025.07.1406

Soichiro Sakamoto, Takahiro Oike, Daijiro Kobayashi, Yuhei Miyasaka, Makoto Sakai, Masahiko Okamoto, Shintaro Shiba, Kento Tomizawa, Narisa Dewi Maulany Darwis, Hanae Yoshida, Mutsumi Tashiro, Tatsuya Ohno

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引用次数: 0

Abstract

Purpose: To evaluate the effects of dose-averaged linear energy transfer (LET_d) profiles on local control of pancreatic cancer treated with carbon ion radiotherapy (CIRT).

Methods and materials: Data from patients with inoperable pancreatic cancer, treated with CIRT and concurrent chemotherapy between 2013 and 2021, were analyzed retrospectively. The prescribed dose was 55.2 Gy (relative biological effectiveness), administered in 12 fractions. The LET_d of CIRT plans were calculated using a previously reported in-house pipeline. The association between tumor LET_d profiles and local recurrence (LR) was analyzed.

Results: The study analyzed 106 patients. The 2-year cumulative LR rate was 20.2% (95% confidence interval [CI], 12.8%-28.9%). Analysis of LET_d parameters using a Fine-Gray regression model showed that the minimum LET_d (L_min) for the clinical target volume (CTV) had a significant effect on LR (p = 0.023). According to the cutoff value of 42.2 keV/μm, determined by time-dependent Receiver Operating Characteristic analysis at 18 months, patients with low CTV L_min had a significantly greater cumulative LR rate than those with high CTV L_min (p = 0.020; 2-year cumulative LR rate, 32.4% [95% CI, 16.6%-49.3%] vs. 12.7% [95% CI, 5.8%-22.5%]). Cause-specific proportional hazards models identified CTV L_min as a significant predictor of LR (hazard ratio, 0.83 [95% CI, 0.71-0.98], p = 0.030). CTV L_min showed a strong significant negative correlation with CTV (p < 0.0001, r = -0.52).

Conclusions: This is the largest study investigating the association between tumor LET_d profiles and local control post-CIRT. The results suggest that low LET_d within the CTV is associated with poor local control in patients with pancreatic cancer treated with CIRT.

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低剂量平均LET与碳离子放射治疗胰腺癌局部复发有关。

目的：探讨剂量平均线性能量转移（LETd）谱对胰腺癌碳离子放疗（CIRT）局部控制的影响。方法和材料：回顾性分析2013年至2021年间接受CIRT和同期化疗的不能手术胰腺癌患者的数据。处方剂量为55.2 Gy（相对生物有效性），分12份给药。CIRT计划的leld是使用之前报告的内部管道计算的。分析肿瘤LETd谱与局部复发（LR）的关系。结果：本研究分析了106例患者。2年累计LR率为20.2%（95%可信区间[CI]， 12.8%-28.9%）。使用Fine-Gray回归模型分析LETd参数显示，临床靶体积（CTV）的最小LETd （Lmin）对LR有显著影响（p = 0.023）。根据18个月时的截断值42.2 keV/μm，低CTV Lmin患者的累积LR率显著高于高CTV Lmin患者(p = 0.020；2年累积LR率,32.4%(95%可信区间,16.6% - -49.3%)和12.7%(95%可信区间,5.8% - -22.5%))。病因特异性比例风险模型确定CTV Lmin是LR的显著预测因子（风险比为0.83 [95% CI, 0.71-0.98], p = 0.030）。CTV Lmin与CTV呈极显著负相关（p < 0.0001, r = -0.52）。结论：这是研究cirt后肿瘤LETd特征与局部控制之间关系的最大研究。结果表明，在接受CIRT治疗的胰腺癌患者中，CTV内低LETd与局部控制不良有关。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Radiation Oncology Biology Physics 医学-核医学

CiteScore

11.00

自引率

7.10%

发文量

2538

审稿时长

6.6 weeks

期刊介绍： International Journal of Radiation Oncology • Biology • Physics (IJROBP), known in the field as the Red Journal, publishes original laboratory and clinical investigations related to radiation oncology, radiation biology, medical physics, and both education and health policy as it relates to the field. This journal has a particular interest in original contributions of the following types: prospective clinical trials, outcomes research, and large database interrogation. In addition, it seeks reports of high-impact innovations in single or combined modality treatment, tumor sensitization, normal tissue protection (including both precision avoidance and pharmacologic means), brachytherapy, particle irradiation, and cancer imaging. Technical advances related to dosimetry and conformal radiation treatment planning are of interest, as are basic science studies investigating tumor physiology and the molecular biology underlying cancer and normal tissue radiation response.