Economic Evaluation of the 21-gene Signature (Oncotype DX) in Lymph Node-negative/positive, Hormone Receptor-positive Early-stage Breast Cancer Based on Japanese Validation Study (JBCRG-TR03)

The 21-gene signature is validated as a good predictor of recurrence for lymph node-negative/positive, hormone receptor-positive, early-stage breast cancer in Japanese patient population. This study evaluates the cost-effectiveness of two scenarios designed to include the assay into Japan's social health insurance benefit package: one for LN-, ER+, ESBC and another for LN-/+, ER+, ESBC. An economic decision tree and Markov model under Japan's health system from the societal perspective is constructed with new evidence from the Japanese validation study. Incremental cost-effectiveness ratios are estimated as ¥384,828 (US$3,848) per QALY for the indication for LN- scenario and ¥568,533 (US$5,685) per QALY for the indication for LN-/+ scenario. Both are not more than the suggested social willingness-to-pay for one QALY gain from an innovative medical intervention in Japan, ¥5,000,000/QALY (US$50,000/QALY). Sensitivity analyses show that this result is plausibly robust, since ICERs do not exceed the threshold by various changes of assumptions made and values employed. In conclusion, the inclusion of the assay in Japan's social health insurance benefit package for not only LN- diseases but also LN+ diseases is cost-effective. Such a decision can be justifiable as an efficient use of finite resources for health care.