CHICAGO – The Oncotype DX, a 21-gene assay that has been shown to be useful in predicting relapse risk in breast cancer patients with no lymph node involvement, can also predict risk of relapse in patients who have up to three positive lymph nodes, according to a poster presented at the annual meeting of the American Society of Clinical Oncology.
“The results of this analysis, aided by ongoing studies, may tell us which patients with early-stage, node-positive breast cancer actually need chemotherapy,” Dr. Lori J. Goldstein, director of the Breast Evaluation Center and leader of the Breast Cancer Research Program at Fox Chase Cancer Center, Philadelphia, said in an interview.
She and her coinvestigators tested the predictive value of the Oncotype DX Recurrence Score (Genomic Health Inc.) in 465 patients who were part of Intergroup Trial E2197, an Eastern Cooperative Oncology Group study of women with early breast cancer treated with standard chemotherapy. Of these patients, 203 had one to three positive lymph nodes, and 262 had no lymph node involvement.
Patients were treated with doxorubicin plus cyclophosphamide if they were hormone-receptor negative, and with docetaxel and hormonal therapy if hormone-receptor positive. The median follow-up was 76 months, and there was no difference in disease-free survival between treatment arms.
Recurrence scores were divided into three categories: low (less than 18), intermediate (18-30), and high (31 or above). The Oncotype DX Recurrence Score was a significant predictor of recurrence in patients with zero to three positive lymph nodes despite treatment with standard chemotherapy. Those whose risk score was less than 18 had excellent outcomes, with less than a 5% risk of recurrence at 5 years; those who had intermediate and high risk scores had a recurrence risk that was two and three times greater, respectively, Dr. Goldstein said.
“These data show the assay can be used to stratify patients at residual risk after being treated with chemotherapy,” said Dr. Soonmyung Paik, director of pathology for the National Surgical Adjuvant Breast and Bowel Project, who was instrumental in developing the assay. “Perhaps patients [with] a high oncotype assay result should be treated with something in addition to chemotherapy. This is an important study,” he said in an interview.