Evaluating Dose Timing (Morning vs Evening) of Endocrine-based Therapies in Metastatic Breast and Prostate Cancers

This study asks a simple but important question: does it matter whether cancer patients take their hormone-based medications in the morning versus the evening? It focuses on patients with metastatic breast cancer or metastatic prostate cancer who are starting hormone therapy combined with a cancer growth inhibitor, and will track symptoms and quality of life in both groups. **You may be eligible if...** - Breast cancer: You have metastatic hormone receptor-positive breast cancer and are starting a CDK4/6 inhibitor (ribociclib or palbociclib) plus endocrine therapy for the first time in the metastatic setting - Prostate cancer: You have metastatic castrate-sensitive prostate cancer and are starting an androgen receptor pathway inhibitor (enzalutamide, apalutamide, or abiraterone) combined with androgen deprivation therapy - You are 18 or older and able to complete questionnaires **You may NOT be eligible if...** - You have any medical reason that prevents taking your medication at a specific time of day - Breast cancer: You are taking abemaciclib (requires twice-daily dosing) - Prostate cancer: You are taking darolutamide or planning to add docetaxel chemotherapy Talk to your doctor to see if this trial is right for you.