title: Societal cost-effectiveness analysis of the 21-gene assay in estrogen-receptor-positive, lymph-node-negative early-stage breast cancer in Japan.
abstract: BACKGROUND
  Breast-cancer incidence and mortality have been increasing in Japan. Japanese-specific clinical validity and utility data for the 21-gene assay (Oncotype DX® Breast Cancer Assay; Genomic Health, Inc., Redwood City, USA) are now available. The objective of this study was to evaluate the cost-effectiveness of the 21-gene assay for the guidance of adjuvant chemotherapy decisions in estrogen-receptor-positive, lymph-node-negative, early-stage breast cancer patients, from the Japanese societal perspective.
  
  
  METHODS
  The recurrence risk group distribution by the 21-gene assay result and the assay's influence on adjuvant chemotherapy recommendations were obtained from a study of 104 patients. A state-transition cohort (Markov) model tracked time from surgery until distant recurrence and from distant recurrence to death. Adjuvant chemotherapy benefit by 21-gene assay risk group was based on published clinical validation studies. Direct and indirect medical costs were obtained from the referral centers. Utilities associated with progression and chemotherapy-related adverse events were extracted from literature. Sensitivity analyses assessed the key drivers and robustness of the primary outcomes.
  
  
  RESULTS
  The 21-gene assay identified 48% of patients as low-risk, 36% as intermediate-risk, and 16% as high-risk. Total acute chemotherapy-related costs decreased by ¥154,066 due to less adjuvant chemotherapy usage. In the high-risk group, adjuvant chemotherapy use increased 18%, leading to survival benefits. Chemotherapy use overall decreased by 19%. Monitoring costs increased by ¥3,744 but recurrence costs declined by ¥46,113 per patient. Use of the 21-gene assay increased quality-adjusted-life-years (QALYs) by 0.241 per patient on average; the net cost per QALY gained was ¥636,752 ($6,368).
  
  
  CONCLUSIONS
  The 21-gene assay for women with estrogen-receptor-positive, lymph-node-negative, early-stage breast cancer is projected to be cost-effective in Japan.
authors.forename: Hideko
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Chizuko
authors.initials: C
authors.lastname: Nakagawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamashige
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takei
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yagata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
authors.forename: Naoki
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Cedar Associates LLC, Menlo Park, CA, USA. ujch@stanford.edu.
authors.forename: John
authors.initials: J
authors.lastname: Hornberger
authors.forename: Tiffany
authors.initials: T
authors.lastname: Yu
authors.forename: Calvin
authors.initials: C
authors.lastname: Chao
authors.forename: Carl
authors.initials: C
authors.lastname: Yoshizawa
authors.forename: Seigo
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D003362:Cost-Benefit Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005820:Genetic Testing / Q000191:economics*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008198:Lymph Nodes / Q000473:pathology*; D008390:Markov Chains; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D011960:Receptors, Estrogen / Q000032:analysis
chemical_list: D004273:DNA, Neoplasm; D011960:Receptors, Estrogen