表观扩散系数值在直肠癌术前放化疗疗效评价中的应用价值

ADC value in preoperative radiochemotherapy for rectal carcinoma

目的探讨表现扩散系数(ADC)值在评估直肠癌术前同步放化疗疗效的可行性及应用价值。方法 20例术前同步放化疗的直肠癌患者,在放化疗前、放疗至10 Gy、放疗至20 Gy及手术前4个监测时间点行磁共振检查,测量ADC值,并测量病灶长度和厚度。将患者放化疗前的临床分期及术后分期比较分为T-降期组和T-未降期组,应用方差分析及独立样本t检验比较肿瘤ADC值、长度及厚度的变化情况。结果两组平均ADC值在放疗前及放疗至20 Gy时差异有统计学意义(P<0.05),其中T-降期组在放疗至20 Gy时平均ADC值较治疗前明显升高,差异有统计学意义(P<0.05)。两组病灶平均长度及厚度在各监测时间点差异均无统计学意义(P>0.05),但两组病灶放化疗前的平均长度及厚度与手术前比较明显减少,差异有统计学意义(P<0.05)。结论术前放化疗对直肠癌的治疗有效。ADC值在早期评价直肠癌术前同步放化疗的疗效方面具有一定的价值。

Objective To monitor early treatment response using apparent diffasion coefficient ( ADC) value to predict response of rectal carcinoma by preoperative radiochemotherapy. Methods Twenty patients with rectal carcinoma were treated with preoperative radio-chemotherapy, followed by surgery. Diffusion-weighted imaging MRI( DWI) was performed in all patients at four-time points ( prior to radio-chemotherapy, dose to 10 Gy, 20 Gy and before surgery) and classified to T-downstaging group and T-no-downstaging group. Variance and independent sample t test were analysed to compare the changes of tumor ADC values, length and thickness between the groups. Results A statistical significant correlation was found between T-downstaging group and T-no-downstaging group in preoperative ADC value (P＜0. 05). In T-downstaging group, the mean ADC value increased significantly compared to the mean ADC value prior to radiochemotherapy at the time point of dose to 20 Gy (P＜0. 05). Before surgery, in T-downstaging group and T-no-downstaging group, the mean length and thickness de-creased significantly compared to the mean length and thickness prior to radiochemotherapy (P＜0. 05). Conclusion Preoperative radioche-motherapy is effective in the treatment of rectal cancer. ADC value in rectal carcinoma is a valuable clinical tool to help assess the therapeutic effect of radiochemotherapy at an early time point.