Establishment of a model to predict the recurrence time of hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer.

[BACKGROUND] For hormonal receptor-positive (HR) breast cancer (BC), about 50% of recurrence occurs after 5-year adjuvant endocrine therapy (late recurrence). It is of great significance to identify the patients with a high risk of late recurrence who might benefit from extended endocrine therapy. This study aimed to construct a model predicting late recurrence of HR/human epidermal growth factor receptor 2-negative (HER2) BC.

[METHODS] In this study, the female patients with HR/HER2 metastatic BC who were treated in the Department of Breast Oncology in Peking University Cancer Hospital were included. These patients were divided into the early recurrence group and the late recurrence group according to disease-free survival (DFS). Predictors for the recurrence time were identified and a nomogram was constructed and validated through concordance index (C-index), area under the curve (AUC), and calibration plots. The clinical data were collected from medical records.

[RESULTS] A total of 639 patients treated in the hospital between April 2007 and October 2019 were included. Median age of these patients at the initial diagnosis of primary tumors was 47 years old. Among them, 382 patients (59.8%) were presented with early recurrence (DFS ≤5 years), and 257 patients (40.2%) were presented with late recurrence (DFS >5 years). The median DFS was 50.0 months. Both univariate and multivariate analyses showed that a higher level of Ki-67 (P=0.005, 0.003) and more positive lymph nodes (P=0.003, 0.021) were associated with shorter DFS. A nomogram based on potentially associated clinicopathological factors was constructed and validation results showed that the nomogram was well-calibrated to predict the recurrence time of these patients (AUC =0.703, C-index =0.697).

[CONCLUSIONS] A well-calibrated nomogram is constructed using the data of clinicopathological factors obtained from 639 HR/HER2 BC patients. Patients with premenopausal status at initial diagnosis, fewer positive lymph nodes and a lower level of Ki-67 were common factors for late recurrence. The nomogram could well predict the risk of late recurrence. Prospectively designed studies are needed to further validate the model.