Abstract P1-01-08: Lymph Node Ratio as an Alternative to pN Staging in Node Positive Breast Cancer: A report from the Korean Breast Cancer Society

Abstract

Background: To compare the lymph node ratio(LNR) and pN staging as a prognostic predictor and find out high risk subgroup which can not predict prognosis using pN staging. Patients and Methods: Using information from two large databases, including Korean nationwide registry, we compared the survival using LNR and pN stage parameters by Cox regression analysis. Moreover survival data were analysed according to age subgroups and intrinsic subtypes. Results: In an analysis of 2264 node positive patients from single institution, adjusted cancer specific mortality risks of low (≥0.20), intermediate (>0.20 and ≥0.65) and high risk (>0.65) LNR groups were 1(reference), 1.9 (95%CI, 1.6 to 2.4), 4.6(95%CI, 3.6 to 5.8). The difference of mortality risk between LNR parameters were wider than that of N1, N2 and N3 in DFS, CSS, OS. In contrast to LNR risk categories, survival curve in pN1 and pN2 overlapped in the patients below 35 years old. Survival curve in pN1 and pN2 also overlapped in patients in her2/neu enriched as well as triple negative subtype. These finding were validated by an analysis of nationwide registry data on 15488 node positive patients. The patients who had N1 and LNR2-3 disease showed poor DFS (HR 1.7 95% CI 1.4 to 2.2) and CSS (HR 1.6, 95% CI 1.1 to 2.2) compared with the patients who had N2 and LNR1 disease. Conclusion: LNR define breast cancer prognosis more adequate than the pN categories especially high risk breast cancer like young age, her2/neu enriched and triple negative intrinsic subtype. It is more reasonable that treatment decision like radiotherapy might be depend on the LNR than pN staging. We argue that LNR should be considered as an alternative to pN staging. Figures available in online version. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-08.