Continuous or Intermittent Pyrotinib for HER2-positive Advanced Breast Cancer

This study compares two dosing schedules — continuous versus intermittent — of pyrotinib, a targeted therapy drug, in women with HER2-positive advanced breast cancer. The goal is to find out if taking breaks from the drug maintains effectiveness while reducing side effects. **You may be eligible if...** - You are 18 or older - You have advanced or locally advanced HER2-positive breast cancer that cannot be surgically cured - You have had at least one prior treatment for advanced disease and your doctor considers you eligible for pyrotinib - You have at least one measurable area of cancer or bone-only disease on imaging - You are in good general health (ECOG 0-1) **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have difficulty taking oral medications or absorbing them due to stomach or bowel issues Talk to your doctor to see if this trial is right for you.