Chemosensitivity During Phases of the Menstrual Cycle in Breast Cancer Patients

This study is investigating whether the phase of a woman's menstrual cycle at the time she receives chemotherapy affects how sensitive her tumor cells are to the treatment. The focus is on women with triple-negative breast cancer, which tends to be more aggressive. **You may be eligible if...** - You are a woman under 60 years old - You have a new diagnosis of triple-negative breast cancer (stages I–III) - You have a regular menstrual cycle and have not yet started any systemic treatment - Your doctor has recommended neoadjuvant chemotherapy (chemotherapy before surgery) **You may NOT be eligible if...** - You are currently using hormonal contraception or have recently stopped - You have started any previous systemic cancer treatment - You are menopausal or have an irregular cycle Talk to your doctor to see if this trial is right for you.