acid ester based antitumor agents specific examples of the antimetabolites include mercaptopurine based antitumor agents methotrexate antitumor agents fluorouracil based antitumor agents and cytosine based antitumor agents specific examples of the antitumor antibiotics include mitomycin c actinomycin d bleomycin based antitumor agents anthracycline based antibiotics and neocartinostatin antitumor agents in addition to those for example aceglatone anastrozole exemestane fadrozole hydrochloride hydrate procarbazine hydrochloride tamoxifen citrate toremifene citrate gefitinib sobuzoxane tamibarotene tretinoin bicalutamide flutamide imatinib mesylate erlotinib hydrochloride sorafenib tosylate sunitinib malate are also included among the antitumor agents orally administrable antitumor agents are preferred from the viewpoints of efficacy and safety as used herein the u201c orally administrable antitumor agent u201d is not particularly limited as long as the agent contains an active ingredient which exhibits an antitumor effect by taking by mouth but it is preferred that the agent contain an active ingredient which is currently marketed in the form of oral preparation among the orally administrable antitumor agents preferred are antimetabolites and particularly preferred are combination preparations thereof from the viewpoint of improving the drug stability the antimetabolites include for example mercaptopurine methotrexate capecitabin carmofur tegafur doxifluridine fluorouracil cytarabine ocphosphate hydroxycarbamide and tegafur uracil and tegafur gimeracil oteracil potassium combination preparations among them a tegafur gimeracil oteracil potassium combination preparation is particularly preferred and a combination preparation in which the molar ratio of the components.