Uft is more antineoplastic against gastric carcinoma than 5-fluorouracil, l-(2-tetrahydrofuryl)-5-fluorouracii and l-hexylcarbamoyl-5-fiuorouracil

The sensitivity of human gastric cancer tissue to 5-fluorouracil (5-FU) and its analogues l-(2-tetrahydrofuryl)-5-fluorouracil (FT), UFT and 1-hexylcarbamoyl-5-fluorouracil (HCFU) was determined, using the in vivo subrenai capsule (SRC) assay. The relative variation of tumor size (ΔTS/TS₀) was calculated as follows: ΔTS/TS₀ = (TS₆-TS₀/TS₀) × 100%, where TS6 was the tumor size on day 6 and TS₀ on day 0. The chemosensitivity was considered to be positive when ΔTS/TS₀ in the treated group decreased to below -10%. For their cytotoxic effects, 5-FU analogues are converted to 5-FU and positive correlations were noted between the tumor sizes of 5-FU and its analogues (5-FU vs. FT, r = 0.737; 5-FU vs. UFT, r = 0.653; 5-FU vs. HCFU, r = 0.709), in gastric tissues from 22 patients. The means ±SD of tumor size were -8.5 ± 11.5% for 5-FU, -8.3 ± 16.0% for FT, -18.1 ± 15.8% for UFT and -13.7 ± 13.4% for HCFU. Decrease in tumor size was marked in case of exposure to UFT, compared with that to 5-FU (p< 0.001), FT (p <0.001) and HCFU (p<0.05). 18% were sensitive to UFT and resistant to 3 other drugs. Thus, UFT proved to be the most effective among 5-FU and its analogues for decreasing the size of gastric cancer tissues.