At 29 years old, Meagan Miraldi was diagnosed with stage 3 breast cancer, while Lilith Costa had a preventative mastectomy at 33. Women 20 to 39 had a 4.1% increase in new breast cancer diagnoses between 1999 and 2018, according to a January CDC report. Newsday's Shari Einhorn has the story. Credit: Kendall Rodriguez; Memorial Sloan Kettering Cancer Center; Photo Credits: Duet Photo and Video, Meagan Miraldi, Lilith Costa