Purpose: A 21-gene recurrence score (RS) assay provides a method of guiding treatment decisions in women with early stage breast cancer. We sought to investigate the cost effectiveness of using the RS assay versus using the Canadian clinical practice guidelines (CCPG).
Method: We developed a Markov model to project the lifetime clinical and economic consequences of the two strategies for patients with early stage breast cancer. The model simulated transitions among the following health states: remission, remission with major chemotherapy-related toxicity, loco-regional recurrence (LR), distant recurrence (DR) and death. We considered 3 scenarios: adjuvant therapy in postmenopausal women with estrogen/progesterone receptor positive (ER+/PR+), axillary lymph node–positive (LN+) early stage breast cancer; postmenopausal women with ER+/PR+, axillary lymph node–negative (LN-) early stage breast cancer; and postmenopausal women with ER+/PR+, LN- early stage breast cancer. We assumed that the RS would independently reclassify patients among risk levels (low, intermediate and high) and corresponding treatment regimens (hormone therapy plus chemotherapy versus hormone therapy alone). The model was parameterized using 5 and 10 year follow up data from the Manitoba cancer registry, cost data from Manitoba administrative databases including the Hospital Discharge Database, the Physician Claims Database and the Drug Program Information Network (DPIN), and secondary sources. Costs are presented in 2010 Canadian dollars, and future costs and benefits were discounted at 5%.
Result: The baseline incremental cost-effectiveness ratio of RS assay versus the CCPG was approximately $3,500/QALY gained for postmenopausal women with ER+/PR+, LN+; $12,000/QALY gained for postmenopausal women with ER+/PR+, LN- ; and $20,000/QALY gained for premenopausal women with ER+/PR+, LN-. Sensitivity analyses revealed that the risk and cost of chemotherapy-related serious adverse effects, the cost of the RS assay and the relative risk reduction of recurrence were the most influential variables.
Conclusion: In all scenarios considered the RS assay appears to be cost effective and should be considered for adoption.
Candidate for the Lee B. Lusted Student Prize Competition