Abstract P5-08-02: Real-life analysis evaluating 1594 N0/Nmic breast cancer patients for whom treatment decisions incorporated the 21-gene recurrence score result: 5-year KM estimate for breast cancer specific survival with recurrence score results ≤30 is >98%

Abstract

Background: The 21-Gene Recurrence Score® Assay (Oncotype DX®) has been validated as a prognostic and predictive tool in estrogen receptor (ER)+ breast cancer in multiple studies using archival specimens of clinical trials with long term follow up. Prospective outcome data from patients where treatment decisions incorporated the Recurrence Score results have not been reported. We evaluated treatments and clinical outcomes in patients undergoing Recurrence Score testing in 9 medical centers within Clalit Health Services (CHS), the largest HMO in Israel. Methods: Medical records of patients with N0/Nmic ER+ HER2-negative disease undergoing testing from 12/2004 to 12/2010 in 9 medical centers (Rabin, Lin, Soroka, Meir, Kaplan, Hadassah, Ha'emek, Rambam, and Shaare Zedek) within CHS were individually reviewed to verify treatments given, recurrence, and survival status. 5-year Kaplan-Meier (KM) and standard error estimates for distant recurrence and breast cancer specific survival were determined. Results: 1594 patients were evaluated with 5.9 years median follow-up. Median age, 61 (25-85) years; N0/Nmic (90%/10%); Grade I (16%), II (48%), III (16%), N/A (19%); histology, IDC (80%), lobular (13%), other (7%). Distribution of Recurrence Score risk groups (Recurrence Score results of <18, 18-30, ≥31): low (51%), intermediate (38%), and high (11%), with chemotherapy (CT) use of 1%, 26%, and 89%, respectively. Distant recurrence was reported in 17/813, 33/612, and 24/169 patients in the low, intermediate, and high Recurrence Score groups, respectively. In the high Recurrence Score group, distant recurrence was reported in 20/150 (13.3%) of CT-treated patients and in 4/19 (21.1%) of untreated patients. In the intermediate Recurrence Score group, the respective values were 9/162 (5.6%) and 24/450 (5.3%). The 5-year KM estimate for distant recurrence rate was 1.4% (95% CI: 0.9-2.3%) for the entire cohort, and 0.5% (95% CI: 0.2-1.6%), 1.2% (95% CI: 0.6-2.8%), and 6.9% (95% CI: 3.7-12.9), for the low, intermediate, and high Recurrence Score groups, respectively. The 5-year KM estimate for breast cancer specific survival was 98.4% (95% CI: 97.6-98.9%) for the entire cohort, and 99.9% (95% CI: 99.0-99.98%), 98.5% (95% CI: 97.1-99.2%) and 90.6% (95% CI: 84.5-94.4%), for the low, intermediate, and high Recurrence Score groups, respectively. Conclusions: These are the first prospective long term clinical outcome data from approximately 1600 patients for whom the 21-gene Recurrence Score assay has been incorporated in real-life clinical decision making. The documented use of CT was appropriately based on the Recurrence Score result, and the outcomes for recurrence and survival are consistent with previously reported prospective-retrospective studies of the 21-gene assay. The 5 year KM estimates for distant recurrence rate in patients with low and intermediate Recurrence Score results who were treated based upon their Recurrence Score results were very low (0.5% and 1.2%, respectively). Citation Format: Stemmer SM, Steiner M, Rizel S, Soussan-Gutman L, Geffen DB, Nisenbaum B, Ben-Baruch N, Isaacs K, Fried G, Rosengarten O, Uziely B, Svedman C, Rothney M, Klang SH, Ryvo L, Kaufman B, Evron E, Zidan J, Shak S, Liebermann N. Real-life analysis evaluating 1594 N0/Nmic breast cancer patients for whom treatment decisions incorporated the 21-gene recurrence score result: 5-year KM estimate for breast cancer specific survival with recurrence score results ≤30 is >98%. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-02.

Breast Cancer—Major changes in the American Joint Committee on Cancer eighth edition cancer staging manual

“…The analyses used conventional AJCC T, N, and M categories as well as tumor grade and ER, PR, and Table 9 summarizes 5-year outcome data from studies using multigene panels to define low-risk patients who were treated predominantly without systemic chemotherapy. [16][17][18][19]21 For such low-risk patients, downstaging to stage I based on biology is supported by the consistently low 5-year risk of recurrence. The major impact of a multigene panel in the eighth edition prognostic stage grouping is the downstaging of biologically low-risk T2 N0 from stage II to stage I for tumors with a low Oncotype DX recurrence score.…”

First Prospective Multicenter Italian Study on the Impact of the 21-Gene Recurrence Score in Adjuvant Clinical Decisions for Patients with ER Positive/HER2 Negative Breast Cancer

“…However, these data suggest that physicians in the Breast DX study were probably reluctant to avoid CT for patients with RS values falling in the “gray area” of 11–17. Other studies reported lower rates of CT+HT use in case of RS 18–25, but these cohorts included almost exclusively patients with node‐negative or N1mi cancer .…”

Oncotype Dx recurrence score among BRCA1/2 germline mutation carriers with hormone receptors positive breast cancer

“…Clinical and pathological characteristics, treatment and outcome were retrieved from medical files of the 27 BRCA carriers treated at Hadassah Medical Center and compared with a cohort of 1594 Israeli patients which was recently published …”