Department of Radiology, Graduate School of Medicine, Osaka City University, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
Radiology. 2013 May;267(2):405-13. doi: 10.1148/radiol.13120249. Epub 2013 Feb 25.
To evaluate whether antitumor immunity is enhanced systemically by combining radiofrequency ablation (RFA) and local injection of an immunostimulant, OK-432.
Experiments were approved by the institutional animal care committee. Experimental Japanese rabbits inoculated with VX2 tumors in the lung and the auricle were randomized into four groups of eight: control (supportive care), RFA (RFA of lung tumor), OK-432 (direct injection of OK-432 into lung tumor), and combination therapy (lung RFA and direct OK-432 injection into lung tumor). All procedures were performed 1 week after implantation of VX2 tumors (week 1). In addition, a VX2 tumor rechallenge test was performed in the RFA and combination therapy groups. Survival time was evaluated by means of the Kaplan-Meier method and by using the log-rank test for intergroup comparison. Mean auricle tumor volumes were calculated every week. Specific growth rates (SGRs) were calculated and compared by using the Mann-Whitney test.
The median survival times of the control, RFA, OK-432, and combination therapy groups were 23, 36.5, 46.5, and 105 days, respectively. Survival was significantly prolonged in the combination therapy group when compared with the other three groups (P <.05). The mean auricle tumor volume decreased only in the combination therapy group. The mean auricle tumor volumes of the combination therapy group from week 1 to week 7 were 205, 339, 264, 227, 143, 127, and 115 mm(3). SGR in the combination therapy group became significantly smaller than those in the other three groups (P < .05). In the rechallenge test, the volume of all reimplanted tumors decreased.
Combining RFA with local injection of immunostimulant OK-432 may lead to indirectly activation of systemic antitumor immunity.
评估射频消融（RFA）联合局部注射免疫刺激剂 OK-432 是否能全身性增强抗肿瘤免疫。
实验得到机构动物护理委员会的批准。实验用接种 VX2 肺肿瘤和耳肿瘤的日本兔随机分为四组，每组 8 只：对照组（支持治疗）、RFA 组（肺肿瘤的 RFA）、OK-432 组（直接向肺肿瘤注射 OK-432）和联合治疗组（肺 RFA 联合直接向肺肿瘤注射 OK-432）。所有程序均在 VX2 肿瘤植入后 1 周（第 1 周）进行。另外，对 RFA 和联合治疗组进行了 VX2 肿瘤再挑战测试。采用 Kaplan-Meier 法和对数秩检验进行组间比较来评估生存时间。每周计算平均耳肿瘤体积。采用 Mann-Whitney 检验计算和比较特定生长率（SGR）。
对照组、RFA 组、OK-432 组和联合治疗组的中位生存时间分别为 23、36.5、46.5 和 105 天。与其他三组相比，联合治疗组的生存时间显著延长（P <.05）。仅在联合治疗组中，平均耳肿瘤体积减小。联合治疗组从第 1 周到第 7 周的平均耳肿瘤体积分别为 205、339、264、227、143、127 和 115mm3。联合治疗组的 SGR 明显小于其他三组（P <.05）。在再挑战测试中，所有再植入肿瘤的体积均减小。
RFA 联合局部注射免疫刺激剂 OK-432 可能会导致全身性抗肿瘤免疫的间接激活。
