Impact of a commercial reference laboratory test recurrence score on decision making in early-stage breast cancer.

Purpose: To investigate whether recurrence score (RS) as determined using a commercial reference laboratory test influences clinicians' treatment recommendations and eventual treatment in patients with early-stage breast cancer.

Methods: A retrospective analysis was performed on 74 patients from a community-based oncology practice with estrogen receptor (ER) -positive, lymph node (LN) -negative stage I or II breast cancer for which RS was obtained. Demographic and pathology information was extracted from medical records. Ten-year relapse-free survival was calculated using Adjuvant! Online. Treatment recommendations before the RS knowledge were compared with treatment recommendations after RS knowledge and to the treatment eventually administered.

Results And Conclusion: A weak correlation was found between RS and both patient age and tumor size, modest correlation between RS and tumor grade, and modest correlation between RS and 10-year recurrence as determined by Adjuvant! Online. For 21% and 25% of patients, knowledge of the RS changed the clinicians' treatment recommendations and eventual treatment, respectively. The decision to change from hormone therapy to chemotherapy (with or without hormone therapy) was generally associated with high RS (high distant recurrence risk as determined by the commercial reference laboratory test), whereas the decision to change from chemotherapy to hormone therapy was generally associated with low RS (low distant recurrence risk as determined by the commercial reference laboratory test). Knowledge of the RS changed treatment recommendations and eventual treatment in patients with ER-positive/LN-negative early-stage breast cancer. Use of genomic-based prognosis may result in more accurate estimates of true recurrence risk than currently possible with commonly used prognostic factors (such as patient age, tumor size, and tumor grade) alone and thus lead to an increase in appropriate adjuvant therapy decision making.