Chen Min-hua, Yang Wei, Yan Kun, Zou Ming-wu, Dai Ying, Gao Wen, Zhang Xiao-peng, Huang Xin-fu
Department of Ultrasound, Clinical Oncology Institute, Peking University, Beijing 100036, China.
Zhonghua Yi Xue Za Zhi. 2004 Feb 2;84(3):203-8.
To develop a preoperative protocol for ultrasonography-guided percutaneous radiofrequency ablation (RFA) on liver tumors larger than 3.5 cm in diameter based on mathematical models and clinical experience, and to evaluate its ablated effect compared to the previous non-math method.
One hundred and twenty-five patients with 80 primary and 55 secondary liver tumors (4.7 +/- 0.9 cm in diameter, ranged from 3.6 - 7.0 cm) were enrolled in this study, of which the first 22 patients (23 tumors) had been treated empirically before the mathematical model was set up and were referred as the non-math group. The rest 103 patients (112 tumors) were treated based on the mathematical model and referred as the math group. Based on principle of overlapping spheres, a mathematical analysis was performed to investigate how multiple ablation spheres could overlap and cover larger tumors most efficiently. Some mathematical models such as regular prism and regular polyhedron model were chosen to estimate the mathematical protocol which included least ablation (sphere) number and optimal overlapping mode required to adequately ablate a large and spherical target lesion. The target volume consisted of the tumor plus a 0.5 - 1 cm tumor-free margin. The operation method for electrode placement was also described.
The procedure success rate for the math group was 88.4% (99/112), local recurrence rate and estimated mean time until local recurrence were 25.9% (29/112) and 17.5 months, respectively. While for the non-math group the results were 52.2% (12/23) (P < 0.01), 56.5% (13/23) (P < 0.05) and 11.9 months (P < 0.05), respectively. The therapy results in the math group were much better than in the non-math group.
This study provides theoretic basis and clinical guidance for RFA therapy for liver tumors larger than 3.5 cm. These results could be used to reduce local recurrence rate and improve treatment response.
基于数学模型和临床经验，制定一种术前超声引导下经皮射频消融（RFA）治疗直径大于3.5 cm肝肿瘤的方案，并与之前的非数学方法比较评估其消融效果。
本研究纳入125例患者，共80个原发性和55个继发性肝肿瘤（直径4.7±0.9 cm，范围3.6 - 7.0 cm），其中前22例患者（23个肿瘤）在数学模型建立之前接受经验性治疗，被归为非数学组。其余103例患者（112个肿瘤）基于数学模型进行治疗，被归为数学组。基于重叠球体原理，进行数学分析以研究多个消融球体如何重叠并最有效地覆盖更大的肿瘤。选择一些数学模型如正棱柱和正多面体模型来估计数学方案，该方案包括充分消融大的球形靶病变所需的最少消融（球体）数量和最佳重叠模式。靶体积包括肿瘤加上0.5 - 1 cm的无瘤边缘。还描述了电极放置的操作方法。
数学组的手术成功率为88.4%（99/112），局部复发率和估计的局部复发平均时间分别为25.9%（29/112）和17.5个月。而非数学组的结果分别为52.2%（12/23）（P < 0.01）、56.5%（13/23）（P < 0.05）和11.9个月（P < 0.05）。数学组的治疗效果明显优于非数学组。
本研究为直径大于3.5 cm的肝肿瘤RFA治疗提供了理论依据和临床指导。这些结果可用于降低局部复发率并改善治疗反应。
