Abstract 1019: Altona regression model: a new prognostic model for breast cancer patients after neoadjuvant treatment

Abstract

Abstract The purpose of the study was to create a new prognostic model for breast cancer (BC) patients that had been treated with a preoperative neoadjuvant chemotherapy, considering different parameters of regressive changes in the residual tumor (RT) respectively the tumor bed (TB). HE-stained whole-slide images of 518 patients, treated between 2001-2019 in Hamburg, Germany following current therapy standards, were analyzed regarding different variables of regressive changes in the pretherapeutic diagnosed BC. First, size of RT and TB was measured, lymph node metastasis and residual intraductal carcinoma in situ were noted. Additional parameters that were examined were cell density and cell shape of RT, heterogeneity of residual tumor cells spreading within the TB and size of the biggest cell clusters as well as changes of the stroma and inflammation within the TB. Data were used pseudo-anonymized after consent was given by the patients and a positive vote of the ethics committee. In the univariate observation of above-mentioned variables it was shown that heterogeneity, cell density and cell shape of residual tumor cells, stroma changes and the presence of lymph node metastases as well as largest diameter and largest cluster of RT have an impact on progression free survival. Using decision tree analysis, the patient cohort could be divided in three risk groups with significant different outcome regarding progression free survival with low, intermediate and high risk for an event (local recurrence of disease, metastasis, death). Our multivariate "Altona regression model", that was constructed using Cox regression, showed significantly better prognostic value concerning progression free survival for BC patients after neoadjuvant therapy and following surgery, compared to two well-known regression gradings by Sinn et al. and MD Anderson (RCB). Comparison of regression models Altona Sinn et al. RCB Altona vs. Sinn Altona vs. RCB Sinn vs. RCB iAUC 0.607 0.350 0.380 < 0.001 < 0.001 < 0.001 Concordance 0.788 0.378 0.478 < 0.001 < 0.001 < 0.001 Citation Format: Anne-Sophie Wegscheider, Katharina Lotfy-Eckmann, Bernhard Ulm, Christoph Lindner, Kay Friedrichs, Axel Niendorf. Altona regression model: a new prognostic model for breast cancer patients after neoadjuvant treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1019.