Abstract P6-10-14: A new model to predict 10-year distant recurrence risk for operable endocrine-responsive breast cancer population
Authors: Lei Lei , Cheng Skye Hung-Chun , Wang Xiao-Jia , Mo Yin-Yuan , Zhou Yun-Yun 
Published: March 2020

Abstract
Background
Few currently available biomarker panels can predict the risk of long-term distant recurrence (DR) in endocrine-responsive breast cancer (ERBC) patients based on lymph-node (LN) status. A new model, DGM-CM6 (Distant Genetic Model-Clinical variable Model 6), has been developed for the prediction of DR risk in our previous studies. To interrogate the prognostic value of our DGM-CM6 model for ERBC patients stratified by LN status, we retrospectively studied 752 operable breast cancer patients treated in a cancer center from 2005 to 2014.
Patients and Methods
Of 752 tumors, a total of 499 ERBC patients was identified from both IHC method (n=490) and PAM50 method (n=404). ERBC patients were classified by high and low-risk groups using the cutoff (&lt;33 or 33) of DGM-CM6 score. Wilcoxon rank sum test was used for the association study between DGM-CM6 score and ERBC subtype status. Kaplan-Meyer survival curves were used to compare the prognostic difference of DRFS and OS in different ERBC risk groups stratified by LN negative (LN-) and positive (LN+) status. Multivariate Cox proportional-hazards regression was used to determine the hazard ratio (HR) of risk groups adjusted by clinical confounders such as treatment and tumor stages.
Results
Significant differences were observed between DGM-CM6 low- and high-risk patients with 10-year DRFS in LN- (ERBC identified by IHC: P = 0.011; by PAM50: P&lt; 0.0001) and LN+ (ERBC identified by IHC: P = 0.015; by PAM50: P = 0.019) by log-rank test. Compared to risk prediction by intrinsic subtype, DGM-CM6 performed better in LN- patients and equally good in LN+ patients. Further multivariate analysis confirmed the independent strength of DGM-CM6 model in the prediction of high- vs. low- risk groups in DRFS (P &lt; 0.0001, HR: 6.76; 95% CI, 1.8-25.42) and OS (P = 0.01, HR: 6.06; 95% CI:1.55-23.47), respectively.
Conclusion
DGM-CM6 model can be used to predict low- and high-risk of 10-year distant recurrence in both LN- and LN+ ERBC patients. This model needs a large scale of clinical trials to validate its clinical utility.
Table 1. Multivariate cox regression analyses for the prognosis of predicted risk groups after adjusted for other clinical variables in the distant recurrence (DR, p=0.005) and overall survival (OS, p=0.01) respectively. Results shows that there is no interaction between chemotherapy and risk groups (DR: p=0.163; OS: p=0.195). Abbreviations: DR, distant recurrence; OS: overall survival.GroupsDROSHR [95% CI]pvHR [95% CI]pvRisk: high vs.low6.76 [1.8;25.42]0.005 ***6.06 [1.55;23.74]0.01 ***Age: &lt;50 vs. &gt;50yrs0.86 [0.51;1.44]0.5630.68 [0.38;1.19]0.175LN: Pos. vs. Neg.1.64 [0.88;3.05]0.1161.6 [0.79;3.22]0.189Stage: II vs. I1.35 [0.76;2.4]0.31.45 [0.76;2.77]0.264Stage: III vs. I2.08 [0.59;7.3]0.2531.59 [0.34;7.46]0.557Grade: 2 vs. 12.14 [0.77;5.97]0.1461.81 [0.63;5.25]0.272Grade: 3 vs. 11.2 [0.4;3.62]0.7481.21 [0.38;3.86]0.752PAM50: Normal vs. LumA0.6 [0.13;2.64]0.4960.7 [0.16;3.16]0.645PAM50: LumB vs. LumA1.58 [0.84;2.98]0.1591.29 [0.65;2.59]0.469PAM50: Her2 vs. LumA0.81 [0.25;2.68]0.7311.01 [0.29;3.47]0.986RT: Yes vs. No0.88 [0.47;1.66]0.7010.71 [0.36;1.41]0.326CT: Yes vs.No0.36 [0.11;1.12]0.0770.3 [0.09;1]0.05 *Interaction: CT vs. Risk0.36 [0.09;1.51]0.1630.36 [0.08;1.68]0.195
Citation Format: Lei Lei, Skye Hung-Chun Cheng, Xiao-Jia Wang, Yin-Yuan Mo, Yun-Yun Zhou. A new model to predict 10-year distant recurrence risk for operable endocrine-responsive breast cancer population [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-10-14.