The influence of a gene expression profile on breast cancer decisions.

Purpose: The Oncotype Dx Recurrence Score (RS), is often employed in patients with estrogen receptor-positive, node negative (ER+LN-) breast cancer. We investigated the impact of the RS on actual chemotherapy administration and the effect of the assay on a panel of breast oncology experts.

Patients And Methods: The prospective adjuvant chemotherapy recommendations (prior to RS) and actual adjuvant therapy (after RS) for consecutive patients with ER+LN- breast cancer were recorded. After 6 months and with the same information, a panel of five experts made adjuvant therapy recommendations with and without RS and rated the strength of their recommendations. Rates of panel consensus, recommendation changes, and changes in recommendation strength were compared.

Results: There were 29 patients (28 women). RS results altered the plan for chemotherapy in 9 patients (31%); 7 of 13 patients (54%) initially recommended for chemotherapy did not receive it, and 2 of 16 (13%) received chemotherapy following initial recommendations against it. RS results changed the panel's chemotherapy recommendation in 7 patients (24%): 5 of 12 (42%) recommendations for changed to against, and 2 of 17 (12%) recommendations against changed to for chemotherapy. RS increased consensus by the panel 10%, but did not increase the reported strength in chemotherapy recommendations.

Conclusions: RS results were associated with real-world decision changes in 31% of patients and 24% of panel recommendations and increased panel consensus by 10%. However RS did not increase the strength of panelist's recommendations.