A Novel Prognostic Nomogram for 2-Year Survival in HER2-Positive Breast Cancer Patients

Background: Targeted therapies have largely improved prognosis of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Yet, disease can still progress rapidly for some patients in the first two years after diagnosis. Our study aimed to establish a nomogram model to predict 2-year breast cancer-specific survival (BCSS) in early HER2-positive breast cancer patients. Methods: A total of 32,481 HER2-positive patients derived from Surveillance, Epidemiology, and End Results (SEER) database were included in the construction of nomogram. Concordance index (C-index) and calibration curve were used to evaluate the discrimination ability and predictive accuracy. We also tested the model in 804 patients from Shanghai Jiao Tong University Breast Cancer Data Base (SJTU-BCDB). Results: Age, estrogen receptor (ER) status, progesterone receptor (PR) status, histologic type, T stage and N stage were selected to construct the nomogram according to multivariable analysis. The 2-year BCSS rate was 95% and 60% for patients at low risk (<8 points) and high risk (>13 scores) respectively. The C-index of model derived from SEER database is 0.81 (95%CI 0.79-0.83). Sensitivity analysis was performed in patients undergoing breast surgeries with the C-index of 0.81 (95%CI 0.79-0.83). Validation in 804 patients from SJTU-BCDB showed respective C-index of 0.77 (95%CI, 0.62-0.92) in total population, 0.67 (95%CI 0.44-0.90) in patients receiving anti-HER2 therapy and 0.90 (95%CI 0.81-0.90) in those without targeted therapy. Conclusions: The novel nomogram can predict 2-year survival outcome in HER2-positive patients independent of receiving anti-HER2 therapy or not and help clinicians to adjust therapeutic strategies for those patients with higher risk.