Figure 1. Patient selection diagram based on data from the National Cancer Database (NCDB) from 2010–2015, applying the defined inclusion and exclusion criteria.

PUF: participant user file. M: metastasis status. cT: clinical tumor size stage. cN: clinical nodal stage. WHO: World Health Organization. ER: estrogen receptor. PR: progesterone receptor. HER2: human epidermal growth factor receptor 2.