Narisawa T, Sato M, Tani M, Takahashi T
J Cancer Res Clin Oncol. 1980;97(3):223-32. doi: 10.1007/BF00405773.
This study deals with the treatment by chemotherapy of carcinogen-induced tumors in the colon of rats. These tumors mimic colonic adenomatosis and carcinomatosis in man. The rats were given an intrarectal (i.r.) instillation of methylnitrosourea for producing colonic tumors, and thereafter received a long-term chemotherapy which was started on nascent microscopic lesions of carcinoma. The colonic tumor incidence was significantly lower in rats treated for 10 weeks than in untreated rats. An inhibition rate of tumor development was 100% in rats with i.r. doses of 5-FU, or 57% in rats with intraperitoneal (i.p.) doses of Ftorafur. However, it was found that a few microscopic lesions of carcinoma were still present in the normal-appearing colonic mucosa, even after the completion of the effective treatment. The 10-week cessation of the treatment following the 5-week chemotherapy permitted the tumor development. The results indicate that the nascent microscopic lesions of carcinoma (premalignant lesions) in the colon can be inhibited or regulated from developing into grossly visible tumors by the effective chemotherapy, i.e., intermittent and/or long-term treatment with sensitive chemotherapeutic agents and effective way of administration.
本研究探讨了化疗对大鼠结肠致癌物诱发肿瘤的治疗效果。这些肿瘤模拟了人类的结肠腺瘤病和癌病。给大鼠直肠内注入甲基亚硝基脲以诱发结肠肿瘤，然后在癌的新生微小病变开始时进行长期化疗。接受10周治疗的大鼠结肠肿瘤发生率显著低于未治疗的大鼠。直肠内注射5-氟尿嘧啶的大鼠肿瘤发展抑制率为100%，腹腔注射喃氟啶的大鼠为57%。然而，发现即使在有效治疗结束后，外观正常的结肠黏膜中仍存在一些微小癌病变。在5周化疗后停止治疗10周会导致肿瘤发展。结果表明，通过有效的化疗，即使用敏感化疗药物进行间歇和/或长期治疗以及有效的给药方式，可以抑制或调节结肠中癌的新生微小病变（癌前病变）发展为肉眼可见的肿瘤。
