Preclinical analysis of the antitumor efficacy of TS-1 using human uterine cervical cancer tumor xenografts.

We investigated the antitumor activity of TS-1 in comparison with that of UFT and cisplatin (CDDP) against cervical cancer using xenografts of a human uterine cervical squamous cell cancer cell line, CaSki, transplanted into female Balb/cA JcL-nu mice. CaSki cell xenografts were prepared by subcutaneous (s.c.) implantation of 3x10(6) cells/animal into the right dorsal region of the mice. The tumor volume was measured twice a week and the relative tumor volume (RTV) was calculated. We divided the animals into four groups according to the treatment administered; TS-1 (10 mg/kg orally, once daily for 14 consecutive days), UFT (24 mg/kg orally, once daily for 14 consecutive days), CDDP (7.6 mg/kg injected intravenously once on the 1st day) and control (no treatment) groups. The antitumor effects of the drugs were measured. On the 35th day after the completion of treatment, the mean tumor volume in the mice treated with TS-1 or CDDP changed from 132.873+/-11.783 mm(3) to 706.401+/-613.122 mm(3) and 133.809+/-19.366 mm(3) to 722.630+/-855.509 mm(3), respectively. The mean tumor volume in the groups treated with TS-1 or CDDP was significantly lower compared to that in the control group (p<0.001; one-tailed Student's t-test). The relative inhibition of the tumor growth was 65.31 in the TS-1 group, 48.31 in the UFT group and 64.51 in the CDDP group. We conclude that TS-1 administered orally for 14 consecutive days showed the highest antitumor activity.