A method for treating cancer in patients with creatinine clearance of 15 mL/min or more and less than 30 mL/min, including dividing a combination drug containing ±,±,±-trifluorothymidine (FTD) and 5-chloro-6-[(2-iminopyrrolidine-1-yl)methyl]pyrimidine-2,4(1H,3H)-dione hydrochloride in a molar ratio of 1 : 0.5, in a dose of 30 to 50 mg/m 2 /day as FTD-equivalent, into two to four times a day, and orally administering it to the patient.
