Development and validation of a survival-predicting nomogram for HER2-negative T1–3N0–1 breast cancer treated with breast-conserving surgery: a Surveillance, Epidemiology, and End Results (SEER) database analysis

We developed the first validated nomograms integrating tumor biology, treatment response, and social factors to optimize HER2-negative BC management. Identifying 'single primary tumor' status as a novel prognostic indicator point to novel tumorigenesis mechanisms. Critically, our findings enable actionable strategies: low-risk patients (33%) may be candidates for avoiding chemotherapy toxicity, while high-risk patients (27%) are potential candidates for more intensive treatment strategies. Patients who fail to achieve a CR should be considered for enrollment in adjuvant trials with novel agents. Adding prospective biomarkers will further refine these precision approaches.