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[Background] Recently, novel anticancer chemotherapy shows good efficacy on gastrointestinal cancer, however, ineffective chemotherapy is still used. We have been performing the MTT chemosensitivity test, objecting advanced gastric cancer patients since 1988, reporting usefulness of the chemosensitivity test in selecting effective anticancer drug in order to avoid inappropriate anticancer drug as adjuvant chemotherapy. [Purpose] In the present study, we re-evaluated accumulated data according to the chemosensitivity test, analyzing the correlation between patients’ prognosis and the results of chemosensitivity test on StageIII or IV gastric cancer patients. [Patients] Two hundreds twenty one patients with histologically diagnosed as gastric cancer “stageIII or IV” between January 1989 and December 2001 were enrolled in the study. [Materials & Methods] We evaluated the in vitro chemosensitivity of fresh surgical specimens, which were obtained during surgery and single-cell suspensions were prepared enzymatically. Tumor cells were suspended and exposed to each anticancer drug(Mitomycin C, 5-FU, Cisplatin, Docetaxel,and Paclitaxel). After incubating for 48 hours, absorbance was measured to calculate inhibition rate. Efficacy of each drug was determined by 30% cut-off inhibition level. The results of chemosensitivity test and survival rate of 193 patients were compared. The patients were divided into three groups, an “Adapted” group treated with at least an effective drug determined by MTT assay, a “Non-adapted” group treated with ineffective drugs by MTT assay, and No chemotherapy group. [Results] There was no statistically significant difference among three groups in background. In StageIII patients, adapted group(n=41) had survival benefit compared to non-adapted (n=19) and no chemotherapy (n=30) groups (p< 0.05). The survival rate of adapted group was 97% in 1 year and 52% in 3 years, while that of non-adapted group was 73% in 1 year and 42% in 3 years, and surgery alone group was 77% and 47% in 1 and 3 years. No significant differences in survival were observed between non-adopted and no chemotherapy groups. In StageIV gastric cancer, the adapted group did not show survival benefit compared to the other two groups. When StageIV patients were categorized in subgroups as to the presence of peritoneal dissemination, liver metastasis, and absence of both peritoneal dissemination and liver metastasis, only Stage IV subgroup with peritoneal dissemination and without liver metastasis showed statistically significant benefit in adapted(n=24) group compared to non-adapted (n =10) group (p<0.05). [Conclusions] Chemosensitivity test with MTT assay will be useful in selection of effective anticancer drugs, and exclusion of ineffective anticancer drugs by the assay will result in improvement in survival and QOL of advanced gastric cancer patients.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]