3.1. Baseline Characteristics in the Training and Validation Cohorts
METASTATIC BREAST CANCER
This study included a total of 682 de novo metastatic breast cancer patients who underwent IBR with complete data from January 2010 to December 2018. After employing R software for random assignment, the training group consisted of 478 patients, while the validation group comprised 204 individuals. The median follow-up times for the training and validation groups were 67 months and 62 months, respectively. Baseline characteristics of the two groups are presented in 