Concentration of S-1 Metabolites in Tear and Plasma of Patients Receiving TS-1

S-1 has been also shown to be an effective drug for palliative chemotherapy in Eastern and Western GC patients. Recently, some case and small-sized studies have been reported on lacrimal drainage obstruction(LDO)caused by S-1.Suggested mechanism of LDO involves direct secretion of S-1 into the tear; thus the concentration of S-1 metabolite in tear is expected to be high in patients who developed LDO than in patients without LDO. We investigate the concentration of S-1 and its metabolites in tear and plasma and find out its correlation with side effects such as LDO. These results will also help us identify patients who are at high risk of developing S-1-associated side effects.