Clinical relevance of 21-gene recurrence score with lymph node involvement in HR+HER2- early breast cancer: A tumor size-match paired cohort study.

Abstract

e12059 Background: Axillary lymph node (LN) involvement is significantly related with high recurrent risk and influenced by tumor size, histologic grade and subtype in early breast cancer. For hormone receptor positive (HR+) and human epidermal growth factor receptor-2 negative (HER2-) breast cancer without LN involvement, 21-gene recurrence score (RS) provides an effective method evaluating the risk of recurrence and metastasis. But the correlation between RS and LN involvement is not clear currently. To investigate the effect of RS on LN involvement, we designed a retrospective cohort study based on the data of tumor size-match LN+/- HR+HER2- breast cancer. Methods: The luminal type (ER+, PR+ and HER2-) early breast cancer (cT1-2) patients with 1~3 LN+ were enrolled and were tumor size-match paired (1:3) with those LN- during the same period. We compared the 21-gene RS between the LN+ and LN- group by univariate and multivariate analyses. Results: From April 2016 to May 2018, there were 65 LN+ cases undergoing 21-gene test included and 195 LN- cases were paired. With tumor size matched, the LN+ group had significantly younger age, more positive family history, higher histologic grade and higher RS than LN- group. All those factors, excepted histologic grade, were further confirmed in multivariate analysis (Table). Conclusions: After adjusted by tumor size, RS may have a significantly independent correlation with LN involvement in HR+HER2- early breast cancer. Total HR+HER2- cases’ tumor size-match paired (1:3) clinic pathologic and RS data. Clinical trial information: NCT03638648. [Table: see text]