Abstract P1-09-14: Breast carcinoma with 21-gene recurrence score lower than 18: Rate of distant metastases in a large series with clinical follow-up
Authors: Wen HY , Krystel-¬Whittemore M , Patil S , Pareja F , Bowser ZL , Dickler M , Norton L , Morrow M , Hudis C , Brogi E 
Published: May 2019

Abstract
Background: The 21-gene recurrence score (RS) estimates the likelihood of distant recurrence and the benefit from chemotherapy in patients with early-stage node-negative, estrogen receptor (ER)-positive, HER2-negative breast carcinoma. The use of the assay resulted in a substantial reduction in adjuvant chemotherapy usage. In this study, we reviewed the outcome of patients with node-negative, ER+/HER2- breast cancer and low recurrence score treated at our center to further verify the prognostic value of the assay.
Design: We identified breast cancer patients treated at our center between 09/2008 and 08/2013 with ER-positive, HER2-negative breast cancer and known RS. We reviewed clinicopathological characteristics, RS, treatment and outcome data. The Institutional Review Board approved the study.
Results: We identified 1406 consecutive patients with early stage node negative ER+/HER2- breast cancer and low RS [RS 0-10: 510 (36%), RS 11-17: 896 (64%)] in the study period. The median age at breast cancer diagnosis was 56 years (range 22-90). Sixty-three (4%) patients were &lt;40 years old at breast cancer diagnosis. A total of 1362 (97%) patients received endocrine therapy, and 170 (12%) received chemotherapy. The median follow up time was 46 months (range 1-85). Six (0.4%) of the 1406 patients developed biopsy proven distant metastases within 5 years of breast cancer diagnosis, 5 of which were in the RS 11-17 group (Table 1). Three of the 5 patients with RS 11-17 and distant metastases were younger than 40 years old at breast cancer diagnosis. In the RS 11-17 group, the absolute incidence of distant metastases among patients with breast cancer diagnosed at age younger than 40 years old is 7.1% (3/42), whereas the absolute incidence of distant metastases among patients ≥40 years is 0.2% (2/854).
Conclusion: Our results suggest that young age (&lt;40 years old) might be a negative prognostic factor even in patients with low RS. Analysis of data from other studies is necessary to further validate this observation.
Table 1. Clinicopathologic characteristics of the 6 patients with ER-positive, HER2-negative, node-negative breast carcinoma of recurrence score &lt;18 who developed distant metastasisPatients#1#2#3#4#5#6Age at diagnosis (years)505437713839Family history of breast/ ovarian cancerNoYesNoNoNoYesPersonal history of breast carcinomaNoIpsilateral DCISNoIpsilateral DCISNoNoTumor typeILCIDCIDCIDCIDCIDCTumor size (cm)2.11.32.72.31.62.1Tumor Grade222223LVINoNoNoNoYesNoER (%)909595959595PR (%)30585757595Oncotype DX RS51212131417SurgeryBTMTMBTMBCSBCSBTMRadiationNoNoNoYesYesNoEndocrine therapyYesYesYesYesNoYesChemoNoNoCMFNoNoNoTime interval to metastasis (months)584125204812Site of metastasisBoneMultipleLungMultipleMultipleBoneFollow-up (months)725359647142SurvivalAWDAWDAWDDODAWDAWDAbbreviations: RS, recurrence score; ILC, invasive lobular carcinoma; IDC, invasive ductal carcinoma; LVI, lymphovascular invasion; BTM, bilateral total mastectomy; TM, total mastectomy; BCS, breast conserving surgery; CMF, cyclofosphamide, metotrexate and 5-fluorouracil. AWD, alive with disease; DOD, died of disease.
Citation Format: Wen HY, Krystel-¬Whittemore M, Patil S, Pareja F, Bowser ZL, Dickler M, Norton L, Morrow M, Hudis C, Brogi E. Breast carcinoma with 21-gene recurrence score lower than 18: Rate of distant metastases in a large series with clinical follow-up [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-09-14.