肝癌射频治疗计算方案的制定及应用研究

目的　超声引导对射频消融治疗后复发率较高的 >3 5cm肝肿瘤 ,通过数学模型计算及临床治疗经验 ,制定术前治疗方案 ,并与非计算治疗方法比较 ,评价肿瘤消融治疗效果。方法　研究对象为肝癌及肝转移癌共 12 5例 135个肿瘤 ,大小 3 6～ 7 0cm(4 7± 0 9cm) ,临床分期Ⅲ～Ⅳ期者占 89 6 % (112 / 12 5例 )。其中 2 2例 (2 3灶 )为开展射频消融早期治疗的病例 ,称非计算组 ,余 10 3例 (112灶 )为根据本计算方案治疗的病例称计算组。计算组为用多个消融灶治疗的肿瘤 ,按照球体数学覆盖原理 ,建立正棱柱体和正多面体数学模型并推导公式进行计算 ,获得覆盖不同大小类球体肿瘤所需的最少消融灶数目及消融定位模式。本研究还制定了实际应用的布针操作程序。结果　临床治疗结果显示 ,计算组肿瘤治疗成功率达 88 4 % (99/ 112灶 ) ,局部复发率为 2 5 9% (2 9/ 112灶 ) ,预测平均无复发时间为 17 5个月 ;非计算组病例 ,肿瘤治疗成功率为 5 2 2 % (12 / 2 3灶 ) (P <0 0 1) ,局部复发率为 5 6 5 % (13/ 2 3灶 ) (P <0 0 5 ) ,预测平均无复发时间为 11 9个月 (P <0 0 5 )。结果显示计算组疗效明显优于非计算组。结论　本研究为较大肝肿瘤射频消融治疗方案的制定 ,提供了理论依据并可指导临床应用 ,治疗结果显示

Mathematical protocol for radiofrequency ablation of liver tumors and its clinical application

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.