Background: Cost
effectiveness analysis of MammaPrint® (70-gene signature) in the diagnosis of early breast cancer as a prognosis assay to study the risk of tumor recurrence to administer adjuvant chemotherapy. Methods: Markov model assuming a cohort of 60-year-old women with breast cancer. Treatment costs and effects were assessed by comparing the 5-year, 10-year and lifetime risk of recurrence using Adjuvant! Online® (online algorithm), 70-gene signature or Oncotype DX® (21-gene assay). Results: 70-gene signature showed a life expectancy of 23.55 years at lifetime. Life expectancy was lower for 21-gene assay and online algorithm, with associated quality-adjusted life year gains up to 0.23 and 0.75, respectively, with 70-gene signature. At year 5, the mean cost of 21-gene assay, 70-gene signature and online algorithm was 7100, 6380 and 4580, respectively. 70-gene signature was dominant versus 21-gene assay at any time horizon and would be cost
effective from year 7 versus online algorithm (lifetime: 1457 per quality-adjusted life years gained). Conclusions: 70-gene signature was a dominant strategy over 21-gene assay and was highly cost
effective versus online algorithm.