QST Hospital, National Institutes for Quantum Science and Technology, Chiba, Japan.
Division of Radiation Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.
Cancer Med. 2023 Jan;12(2):1540-1551. doi: 10.1002/cam4.5045. Epub 2022 Jul 19.
To evaluate the clinical relative biological effectiveness (RBE) of carbon-ion radiotherapy (C-ion RT) for prostate cancer.
The records of 262 patients with low-risk prostate cancer (median age, 65 [47-80] years) treated with C-ion RT at QST Hospital, National Institutes for Quantum Science and Technology in Japan during 2000-2018 were reviewed retrospectively. Four different protocol outcomes and prostate-specific antigen (PSA) responses were evaluated. The median follow-up was 8.4 years. The Kaplan-Meier method was used to estimate the biochemical or clinical failure-free rate (BCFFR). Clinical RBE was calculated using the tumor control probability model.
The 5-, 7-, and 10-year BCFFRs were 91.7%, 83.8%, and 73.2%, respectively. The 10-year BCFFRs of patients who received C-ion RT at 66 Gy (RBE) in 20 fractions, 63 Gy (RBE) in 20 fractions, and 57.6 Gy (RBE) in 16 fractions were 81.4%, 70.9%, and 68.9%, respectively. The PSA level and density during follow-up were better in the patients treated with the lower fraction size. A higher PSA nadir and shorter time to PSA nadir were risk factors for biochemical or clinical failure by multivariate Cox regression. The tumor control probability analysis showed that the estimated clinical RBE values to achieve an 80% BCFFR at 10 years for 20, 16, and 12 fractions were 2.19 (2.18-2.24), 2.16 (2.14-2.23), and 2.12 (2.09-2.21), respectively.
Using clinical data from low-risk prostate cancer patients, we showed the clinical RBE of C-ion RT decreased with increasing dose per fraction.
评估碳离子放疗（C-ion RT）治疗前列腺癌的临床相对生物学效应（RBE）。
回顾性分析 2000 年至 2018 年期间在日本量子科学与技术研究所国立研究所 QST 医院接受 C-ion RT 治疗的 262 例低危前列腺癌患者（中位年龄 65[47-80]岁）的病历。评估了四种不同的方案结果和前列腺特异性抗原（PSA）反应。中位随访时间为 8.4 年。采用 Kaplan-Meier 法估计生化或临床无失败率（BCFFR）。使用肿瘤控制概率模型计算临床 RBE。
5、7 和 10 年的 BCFFR 分别为 91.7%、83.8%和 73.2%。在接受 66Gy（RBE）20 分次、63Gy（RBE）20 分次和 57.6Gy（RBE）16 分次 C-ion RT 的患者中，10 年 BCFFR 分别为 81.4%、70.9%和 68.9%。随访期间 PSA 水平和密度在接受较小分次剂量治疗的患者中更好。多变量 Cox 回归分析显示，较高的 PSA 最低点和 PSA 最低点时间较短是生化或临床失败的危险因素。肿瘤控制概率分析表明，要在 10 年内达到 80%的 BCFFR，20、16 和 12 分次时估计的临床 RBE 值分别为 2.19（2.18-2.24）、2.16（2.14-2.23）和 2.12（2.09-2.21）。
使用低危前列腺癌患者的临床数据，我们表明 C-ion RT 的临床 RBE 随剂量分次的增加而降低。
