The Impact of the 21-gene Recurrence Score Assay on Decision Making About Adjuvant Chemotherapy in Early-stage Estrogen-receptor-positive Breast Cancer in an Oncology Practice With a Unified Treatment Policy

D. B. Geffen; S. Abu-Ghanem; N. Sion-Vardy; R. Braunstein; M. Tokar; S. Ariad; B. Delgado; M. Bayme; M. Koretz

Disclosures

Ann Oncol. 2011;22(11):2381-2386. 

In This Article

Patients and Methods

The Oncology Institute of the Soroka University Medical Center provides treatment and follow-up to ~250 new BC patients per year. Included in this retrospective study were patients with stage I to II BC on whose tumor specimen RS was obtained. We started offering the test in 2006 when the largest HCO began funding it.[14] The departmental policy was to recommend the test to those patients with T1-2N0M0 ER-positive, human epidermal growth factor-2 (HER2)-negative BC who had no contraindications to chemotherapy or tamoxifen. Clinical judgment also was a factor in deciding who was tested. We obtained the RS on very few high histological grade patients because of a report that 74% of high-grade patients had high-risk RS and our hesitation about utilizing a new test to deny chemotherapy to patients that always had been thought to benefit from it.[2] ER, progesterone receptor (PR) and HER2 were determined by immunohistochemical (IHC) staining. HER2 was considered positive if IHC staining was +3. For IHC +2 cases, chromogenic in situ hybridization was carried out to determine HER2 status. During the study period, ~130 patients with HER2-positive early BC were seen in our practice. Axillary node-positive patients were included only in the latter part of the study period. The test was carried out by Genomic Health on paraffin-embedded tissue from surgical specimens or biopsies as described elsewhere.[2,3] The patient signed informed consent for the RS as part of routine clinical practice. We used AO (version 8.0) to calculate the 10-year survival advantage of adding anthracycline-based chemotherapy for each patient. Clinical and pathological data were obtained from a prospectively maintained database of BC patients as well as from patient charts. Before obtaining the RS, we generally recommended chemotherapy when projected survival advantage by AO calculation was >1%. Our treatment recommendation policy, which we based on the originally suggested RS risk grouping,[2,3] is shown in Table 1. Intermediate risk RS patients generally received treatment recommendations as if the RS had not been obtained, using traditional clinicopathological features and AO to aid in the decision. The Soroka Medical Center Institutional Review Board approved the study.

Statistical Analysis

Quantitative data are presented using means ± standard deviations (SD) with medians and ranges also shown. Categorical data are presented using percentages. Fisher's exact and McNemar's tests were used to examine the difference between the proportions of patients who had treatment recommendations changed to adding chemotherapy and who had recommendations changed to endocrine therapy only. Student's t-tests were carried out for the influence of histological grade, T stage and N stage on the outcome of treatment recommendation changed versus not changed. The Pearson's correlation coefficient was used to determine the correlation between RS and AO projected 10-year survival benefit from chemotherapy. Statistical analyses were carried out using SPSS v.14 statistical software (SPSS Inc., Chicago, IL).

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