Abstract PS6-18: Are we missing something? Ki-67 evaluation is important in African American women with an oncotype DX score&lt; 26: A multi-institutional study
Authors: Turner Bradley M , Gimenez-Sanders Mary Ann , Zhang Huina , Moisini Ioana , Wang Xi , Schiffhauer Linda , Katerji Hani , Skinner Kristin , Gooch Jessica , Shayne Michelle , Ling Marilyn , Falkson Carla , Hicks David 
Published: February 2021

INTRODUCTION: The literature suggests that there is no difference in the Oncotype DX® (ODX) recurrence score between African American (AA) women and Caucasian (CA) women; however, an analysis of clinical outcomes in participants enrolled in the TAILORx trial found that AA women had worse clinical outcomes than CA women, despite similar ODX recurrence scores. The TAILORx trial suggested that chemoendocrine therapy may not be necessary in women with hormone-positive, HER2-negative, node-negative invasive breast carcinomas with an ODX recurrence score &lt; 26. We examine Ki-67 (a marker of tumor proliferation) in relation to an ODX recurrence score of 26 in AA and CA women from two seperate institutions. METHODS: A total of 851 consecutive cases of AA (n = 78) and CA women (n = 773) with ER+ invasive breast cancer and available ODX recurrence scores from the University of Rochester and the University of Louisville were included in this study. For all results, a p-value of &lt; 0.05 was considered significant. RESULTS: Consistent with the previous literatuere, there was no significant difference between the average ODX recurrence score of AA and CA women (p = 0.44, Table 1), and we found no significant difference in average ER, PR, Nottingham score, or tumor size between AA and CA patients; however, the Ki-67 was significantly higher in AA patients with an ODX recurrence score &lt; 26 compared to CA patients with and ODX recurrence score &lt; 26 (p = 0.002, Table 2). This significant difference in Ki-67 was not evident with an ODX recurrence score ≥ 26 (p = 0.98, Table 2). CONCLUSIONS: Our preliminary results suggest that compared to CA women, AA patients are more likely to have a higher Ki-67 if the ODX recurrence score is &lt; 26. AA breast cancer patients with an ODX &lt; 26 are at increased risk for recurrence compared to CA women with an ODX &lt; 26. Ki-67 evaluation is not routinely done as part of the breast cancer workup in many institutions. Ki-67 evaluation may be helpful to help guide treatments decisions in AA patients with and ODX &lt; 26. Additional investigation is warranted.

Table 1: Oncotype DX and histopathologic variables for African American and Caucasian womenODXRS* (mean)ER** (mean)PR** (mean)NS***(mean)Ki-67 (mean)****Tumor size (mean)ODXRS &lt; 26 (n) ODXRS ≥ 26 (n)ALL17.6255.3168.96.016.42.2713138AA18.3250.7175.96.321.42.26315CA17.5255.8168.26.015.92.2650123*Oncotype DX recurrence score** modified H-score*** Nottingham score****n = KI-67 available for 777 total patients (650 with ODXRS &lt; 26 and 127 with ODXRS ≥ 26); KI-67 available for 71 AA patients (51 with ODXRS &lt; 26 and 14 with ODXRS ≥ 26); KI-67 available for 706 CA patients (593 with ODXRS &lt; 26 and 113 with ODXRS ≥ 26)

Table 2: Oncotype DX &lt; 26 and ≥ 26 and associated histopathologic variables for African American and Caucasian womenODXRS* (mean)ER** (mean)PR** (mean)NS*** (mean)Ki-67 (mean)****Tumor size (mean)ODXRS &lt; 2614.5260.5189.15.813.72.2AA15.4262.8200.76.019.22.3CA14.4260.3188.05.813.12.2ODX ≥ 2633.8228.464.47.330.52.1AA30.3199.871.97.730.41.6CA34.2231.963.57.330.52.2*Oncotype DX recurrence score** modified H-score*** Nottingham score****n = KI-67 available for 777 total patients (650 with ODXRS &lt; 26 and 127 with ODXRS ≥ 26); KI-67 available for 71 AA patients (51 with ODXRS &lt; 26 and 14 with ODXRS ≥ 26); KI-67 available for 706 CA patients (593 with ODXRS &lt; 26 and 113 with ODXRS ≥ 26)

Citation Format: Bradley M Turner, Mary Ann Gimenez-Sanders, Huina Zhang, Ioana Moisini, Xi Wang, Linda Schiffhauer, Hani Katerji, Kristin Skinner, Jessica Gooch, Michelle Shayne, Marilyn Ling, Carla Falkson, David Hicks. Are we missing something? Ki-67 evaluation is important in African American women with an oncotype DX score&lt; 26: A multi-institutional study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-18.