Experimental radiology for prevention and control of metastasis

本研究旨在获得临床上有用的基本信息。肿瘤的血行转移过程可分为三个阶段，即肿瘤细胞从原发部位释放到血液循环、转运、停滞和在继发部位生长。这些步骤都是预防和治疗转移研究中必须考虑的重要步骤。第一年，我们研究了中子照射局部肿瘤对克隆性肿瘤细胞释放和转移形成的影响。结果表明，中子比X射线更能有效地抑制克隆性肿瘤细胞的释放和转移。在这一年里，研究了瘤内注射OK432对肿瘤转移形成的影响，包括免疫原性和非免疫原性的肿瘤系统。只有瘤内注射对非免疫原性肿瘤系统有效，尽管无论是I.P还是I.M./S.C.瘤内注射OK-432抑制肺转移形成与减少克隆性肿瘤细胞向血液循环的释放是平行的。

The present study aimed to obtain basic infomaiton, which could be useful in clinical situation. The processes of hematogenous metastasis can be divided into three steps,i.e., tumor cell release from the primary into the blood circulation, transportation, arrest and growth at the secondary site. All of these steps are important and have to be considered in the study for prevention and treatment of metastases.In the first year, we studied effect of neutron irradiation of local tumors on clonogenic tumor cell release and metastasis formation. The results indicated neutron suppressed clonogenic tumor cell release and metastasis more effectively than X-rays. In the current year, the effect of intratumoral injection of OK432 on metastasis formation was investigated using various tumor systems including immunogenic or nonimmunogenic. Only intratumoral injection was effective in nonimmunogenic tumor systems although either i.p or i.m./s.c. in the opposite leg to the inoculated tumor was aslo effective in immunogenic tumor systems.The suppression of lung metastasis formation by intratumoral injection of OK-432 was paralleled with the reduction of clonogenic tumor cell release into the blood circulation.