Leah Siegel's story starts on what should be one of the happiest days of her life. As she snuggled with her newborn son, Oliver, she could never imagine just how drastically her life was about to change. Five days after the delivery, doctors finally determined through a bone marrow biopsy that the 42-year-old had an aggressive form of estrogen-fueled breast cancer that had spread to her bones. It's called lobular carcinoma.