title: Cost-minimization analysis of adjuvant chemotherapy regimens given to patients with colorectal cancer in Japan.
abstract: BACKGROUND
  Consideration of medical costs as well as effectiveness and adverse events is rapidly been becoming an important factor in the selection of chemotherapy regimens. However, practical data on the costs of chemotherapy are scarce. We clinically estimated the medical costs of 6 adjuvant chemotherapy regimens for colorectal cancer on the basis of clinical and cost-related data and compared their cost-effectiveness by cost-minimization analyses.
  
  
  METHODS
  All patients who received adjuvant chemotherapy for colorectal cancer between April 2012 and May 2015 at four hospitals affiliated with Showa University were studied retrospectively. Clinical and cost data related to adjuvant chemotherapy were collected from medical records and medical fee receipt data, respectively. Six adjuvant chemotherapy regimens were studied: capecitabine and oxaliplatin (CapeOX); 5-fluorouracil (5-FU), ℓ-leucovorin (LV), and oxaliplatin (modified FOLFOX6 [mFOLFOX6]); 5-FU and LV (5-FU/LV); tegafur and uracil (UFT), and LV (UFT/LV); capecitabine; and tegafur, gimeracil and oteracil (S-1). The regimens were divided into 2 groups according to whether or not they contained oxaliplatin because of the difference in effectiveness. Cost-minimization analyses, where relative costs of regimens showing equivalent effectiveness were simply compared, were performed to evaluate the cost-effectiveness of the regimens in each group.
  
  
  RESULTS
  A total of 154 patients with colorectal cancer received adjuvant chemotherapy during the study period. Fifty-seven patients were treated with CapeOX, 10 with mFOLFOX6, 38 with UFT/LV, 20 with capecitabine, and 29 with S-1. No patient received 5-FU/LV. The total costs of oxaliplatin-containing regimens were significantly higher than those of oxaliplatin non-containing regimens. The high cost of oxaliplatin, but not the costs of drugs or various tests for the treatment of adverse events, was the primary reason for the higher costs of the oxaliplatin-containing regimens. The cost-effectiveness of the oxaliplatin-containing regimens CapeOX and mFOLFOX6 were comparable. Among the oxaliplatin non-containing regimens, the cost-effectiveness of S-1 and capecitabine was superior to that of UFT/LV.
  
  
  CONCLUSIONS
  Thus, we provided the cost-effectiveness data of 5 adjuvant chemotherapy regimens for colorectal cancer based on practical clinical and cost data from Japanese patients. The results can be included as a factor in regimen selection because these results would represent the real world.
  
  
  BACKGROUND
  This study is a retrospective observational study and does not include any health care interventions. Therefore, we did not register the protocol of this study.
authors.affiliation: Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Takata
authors.affiliation: Institute of Molecular Oncology, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Fujita
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Hiroo
authors.initials: H
authors.lastname: Ishida
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Kanagawa 227-8501 Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Ichikawa
authors.affiliation: Department of Internal Medicine, Showa University Koto Toyosu Hospital, 5-1-38 Toyosu, Koto-ku, Tokyo, 135-8577 Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Shimada
authors.affiliation: Department of Internal Medicine, Showa University Yokohama Northern Hospital, 35-1 Chigasakichuo, Tsuzuki-ku, Yokohama, Kanagawa 224-8503 Japan ; Division of Medical Oncology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Kanagawa 227-8501 Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sekikawa
authors.affiliation: Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Iori
authors.initials: I
authors.lastname: Taki-Takemoto
authors.affiliation: Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kamei
authors.affiliation: Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Iwai
authors.affiliation: Institute of Molecular Oncology, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan ; Division of Medical Oncology, Department of Internal Medicine, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555 Japan.
authors.forename: Yasutsuna
authors.initials: Y
authors.lastname: Sasaki
keywords: Adjuvant chemotherapy; Colorectal cancer; Cost-effectiveness; Cost-minimization analysis; Regimen selection