Antineoplastic Efficacy Of Metronomic Scheduling Of Gemcitabine Chemotherapy In Lewis Lung Cancer Allografts Compared To Conventional Scheduling

[Objectives] Continuous low-dose metronomic chemotherapy called antiangiogenic chemotherapy, can suppress the growth and metastasis of tumor by inhibiting angiogenesis, which theoretically presents the possibility of delaying or even avoiding the onset of acquired drug resistance. Gemcitabine often used in non-small cell lung cancer in clinic has shown certain antiangiogenic effects in vivo before. This study was proposed to investigate the antineoplastic efficacy of low dose metronomic gemcitabine compared to conventional scheduling, as well as the possible inhibitory mechanisms.[Methods] In this experiment, Lewis Lung cancer allografts wereestablished in C57B1/6 mice. Forty one mice were randomly divided intothree groups, that is control one treated by normal saline, low dose gem one(gemcitabine 10mg/kg, q3d) and conventional scheduling gem one(gemcitabine 100mg/kg, qw, continuous in a three-week time and spacedone week) . The survival , tumor growth and metastasis to lung and lifequality were investigated. Finally, the level of VEGF, Caspase-3, Bax and Bcl-2 were measured immunohistochemistrically. Statistical analysis depended on SPSS 11.0.[Results] The two experiment groups showed no difference in survival time compared with the control team, but had significant efficacy in tumor inhibition. The low dose gem demonstrated privilege in inhibiting metastasis to lung while the conventional gem showed no difference with the control one. The low and conventional gem both were tolerant in their way. The level of VEGF in low dose gem regimen had a decrease tendency showing no difference with the conventional scheduling gem. They two both expressed Caspase-3 in a relative high level. Also the ratio of Bax/Bcl-2 was high in them, preferably more in the conventional gem regimen.[Conclusions] Low dose mechonomic scheduling of gemcitabine had a certain efficacy in tumor inhibition and more preferable tumor metastasis inhibition with good tolerance. Its effects might result from antiangiogenesis and apoptosis.