Combination of metronomic capecitabine and letrozole in metastatic hormone receptor positive, HER2 negative breast cancer: a randomized phase II trial.

First line endocrine therapy is the gold standard for advanced estrogen receptor positive, human epidermal growth factor receptor 2 negative breast cancer. Adding CDK4/6 inhibitors has improved progression free survival. Metronomic Capecitabine has proven to be safe to combine with endocrine therapy with promising efficacy.