Prognostic model for pulmonary metastasis in patients with HER2-positive breast cancer: a population-based study.

BACKGROUND: Lung metastasis is an important adverse prognostic factor in patients with HER2-positive breast cancer. However, a lack of an accurate estimation of the prognosis of patients with lung metastasis and the validation of population-based models has been observed. In this study, we aimed to establish a nomogram based on the surveillance, epidemiology, and end results (SEER) database to determine the prognostic factors associated with lung metastasis and evaluate the individualized survival of patients with lung metastasis. METHODS: This study included 613 patients diagnosed with HER2-positive breast cancer with lung metastasis (HER2 + BC-LM) from the SEER database and randomly divided them into two groups: (1) training group (n = 432) and (2) test group (n = 181). Based on the univariate and multivariate Cox regression analyses, we assessed the impact of multiple variables on the survival of the patients in the training group and constructed a nomogram to predict the survival probabilities of the patients at 6 months, 1 year, and 2 years. Furthermore, the nomogram was validated by the concordance index (C-index) and calibration plots. RESULTS: A prognostic model for predicting the prognosis of patients with HER2 + BC-LM was established and validated. For the patients diagnosed with HER2 + BC-LM, the C-index (0.813 in the training group and 0.787 in the validation group, respectively) and calibration plots revealed that the prognostic accuracy and clinical applicability of the nomogram were acceptable. The surgical resection of the primary tumor and chemotherapy were found to be significantly associated with better overall survival (OS). CONCLUSION: A sensitive and discriminatory model was established to predict the OS of patients with HER2 + BC-LM.