Sharon is a 60-year-old woman with metastatic breast cancer that was originally diagnosed in 2005 and treated with a mastectomy, deep inferior epigastric artery perforator flap reconstruction, chemotherapy, post mastectomy radiation, and five years of tamoxifen. Three months ago, her breast cancer recurred, and staging scans demonstrated metastatic disease in the lungs, left axilla, liver, and left iliac bone. A biopsy of the left iliac bone was ER positive, PR negative, and HER2 negative. Sharon began treatment with radiation to the painful left hip and letrozole, with the plan to start palbociclib once radiation was completed.