Purpose: To survey the effect of the 21-gene recurrence score (RS) assay results on adjuvant treatment recommendations for patients with lymph node-positive (N+), estrogen receptor-positive (ER+) breast cancer.
Methods: Medical oncologists who ordered the 21-gene RS assay were invited to complete a survey regarding their most recent patient with N+/ER+ breast cancer. We obtained responses from 160 (16%) of the 1,017 medical oncologists.
Results: Most of the respondents were in community (71%) versus academic (25%) settings and had practiced for a median of 11 years. T1, T2, or T3 disease was reported in 62%, 35%, and 3% of patients, respectively. One, two, three, or ≥ 4 nodes were reported in 69%, 18%, 6%, and 3% of patients, respectively. Eighty-six percent of the oncologists made treatment recommendations before obtaining the RS; 51% changed their recommendations after receiving the RS. In 33%, treatment intensity decreased from chemotherapy plus hormonal therapy to hormonal therapy alone. In 9%, treatment intensity increased from hormonal therapy alone to chemotherapy plus hormonal therapy. In 8%, treatment recommendations changed in a way that did not fit the definition of either increased or decreased intensity.
Conclusion: In this survey of physician practice, the RS result was used to guide adjuvant treatment decision making in N+/ER+ breast cancer more often in patients with tumors less than 5 cm in size and one to three positive lymph nodes than in patients with larger tumors and four or more positive nodes and yielded an overall reduction in recommendations for chemotherapy.