Survival Outcomes and Prognostic Staging in Locally Advanced Breast Cancer Patients Receiving Radiotherapy: A Single Center Experience

Abstract

The American Joint Committee on Cancer (AJCC) 8th edition prognostic staging was introduced to improve breast cancer staging by incorporating factors like hormone receptor status and human epidermal growth factor receptor-2 (HER2) expression. This study assesses its effectiveness in locally advanced breast cancer (LABC). A total of 557 patients with locally advanced breast cancer (Stage III) were re-evaluated using prognostic staging. Overall survival (OS), disease-free survival (DFS), and distant metastasis free survival (DMFS) rates were evaluated using the Kaplan-Meier method, and the log-rank test was employed to compare outcomes between anatomic and prognostic staging. According to restaging 34.5% of patients remained in the same stage, while 55.8% were downstaged, and 9.7% were upstaged. When patients reassigned using prognostic staging patients classified as stage IIA showed improved OS rates compared to those in stages IIIA, IIIB, and IIIC (p< 0.001 for each). Patients with prognostic stage IIA had better DFS compared to IIIA, IIIB (p= 0.003, and p< 0.001, respectively). Both anatomic and prognostic staging were found to significantly impact OS in patients with Luminal-A tumors (p= 0.008 and p= 0.001, respectively), whereas neither anatomic nor prognostic stage had any impact on triple negative subgroup. When stage IIIA patients restaged, downstaged individuals showed better OS than those who stayed at the same stage or were upstaged (p= 0.01 and p= 0.02, respectively). This study highlights the prognostic staging system’s superiority over anatomic staging in predicting survival outcomes for LABC, and the use of the prognostic staging system for more personalized treatment strategies. Keywords: Breast cancer, Radiotherapy, Anatomic staging, Prognostic staging