Abstract P5-08-41: Prognostic contribution of mammographic breast density and HER-2 overexpression to the Nottingham prognostic index in patients with invasive breast cancer

Abstract

Abstract Purpose: To examine the associations between very low mammographic breast density (VLD), HER2, ER and PR status in a more homogenized patient group within matched NPI categories. We also aimed to investigate whether those variables could be added to the NPI to enhance its prognostic and predictive values and better categorize which patients are at higher risk. Materials and methods: A total of 270 patients with invasive breast cancer were included in the final analysis. Patients with mammographic breast density of <10% were considered as VLD. We compared the performance of NPI with and without ER, PR , VLD and/or HER2. Factors first underwent univariate and then multivariate analysis to assess the factors combined until the best fit was obtained. Cox multivariate analysis, time-dependent receiver operating characteristic curve (tdROC), concordance index (c-index) and prediction error (i.e. 0.632+ bootstrap estimator) were used to derive an updated version of NPI. Patients' survival was assessed by the Kaplan-Meier method using a log rank (Mantel-Cox) test. Results: The average NPI value was 4.66 (range 2.12-7.40), the percentage of HER2 positive patients progressively increased from the low to the high prognostic groups of NPI (p<0.001). While MBD, ER and PR status showed no such difference in distribution. Patients showed survival differences in the intermediate and high risk groups of NPI according to VLD and HER2 status (p<0.001 and p=0.02, respectively). Outcome analysis showed that the addition of both factors combined provides improved patient outcome stratification superior to the traditional NPI helping to significantly decrease the percentage of patients in the intermediate patient groups. Conclusion: VLD breasts and HER2 positivity are prognostic factors for breast cancer independent of the NPI. Moreover, their addition to the NPI helps increase its prognostic accuracy and reduces the percentage of patients in the intermediate prognostic group. Citation Format: Masarwah A, Sudah M, Sutela A, Päivi A, Ritva V. Prognostic contribution of mammographic breast density and HER-2 overexpression to the Nottingham prognostic index in patients with invasive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-41.