Abstract P2-01-24: Evaluating lymph node ratio (LNR) as a prognostic indicator in node-positive breast cancer

Abstract

Abstract Purpose: To determine whether LNR can provide additional prognostic information to pN staging in node-positive breast cancer patients. Methods: We previously reported on the utility of LNR as a prognostic indicator in lymph node-positive early breast cancer. We present an updated analysis with a prolonged median follow-up of 85 months. A retrospective review of original histopathology reports was undertaken in a sample group of 214 patients diagnosed with node-positive breast cancer between January 2000 and January 2011. The LNR was defined as the number of positive lymph nodes divided by the total number of lymph nodes (LNs) removed. LNR cut off points were divided into low (≤0.14), intermediate (0.15-0.39) and high (≥0.40) by trichotomy. Patients were also divided into three groups based on nodal status in accordance with the AJCC staging system. Those with 1-3 positive nodes were classified as pN1, those with 4-9 positive nodes were pN2 and those with 10 or more positive nodes were classified as pN3. Overall survival (OS) and invasive Disease Free Survival (iDFS) were calculated using the Kaplan Meier Method. Results: The mean age at diagnosis was 58 (SD=12) years. The median follow-up time was 85 months. The 5-year OS and iDFS for node-positive patients were 80% and 70%, respectively. The mean number of lymph nodes examined was 15.2 (SD=6.6) and the mean number of positive nodes was 5.3 (SD=6.1). When patients were stratified according to LNR groupings OS was 80% in the low LNR group, decreasing to 67% in the intermediate LNR group and 47% in the high LNR group (p<0.0001). Similarly, iDFS in the low LNR group was 71% decreasing to 57% in the intermediate LNR group and 42% in the high LNR group (p<0.0009). Conclusions: These updated results from a cohort of patients with lymph node-positive early breast cancer at a median follow-up of over 7 years confirms the utility of LNR as a prognostic indicator. Univariate and multivariate analyses to assess the ability of LNR to discriminate risk in addition to AJCC nodal grouping will be presented. Citation Format: Kelliher A, Boyce M, Donnellan E, O Connor D, Murphy C, Bird B. Evaluating lymph node ratio (LNR) as a prognostic indicator in node-positive breast cancer [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 P2-01-24.