A Harvard Medical School professor is speaking out after being diagnosed with the same type of breast cancer she has spent her career researching.
Dr. Jennifer Guerriero, an instructor in medicine at Harvard and director of a research lab at Brigham and Women's Hospital in Boston, was diagnosed with hormone receptor-positive breast cancer this spring, at the age of 43.
"I knew the science. I knew the biology of breast cancer, but nothing prepared me to hear the words, 'I have cancer,'" Guerriero told ABC News.
Guerriero said she received her diagnosis after undergoing a routine mammogram.
"I didn't have any symptoms. I didn't have a lump," she said. "I just went in as part of the annual mammogram screen."
Guerriero said she underwent a double mastectomy in August and feels lucky that her cancer was detected early.
"My surgeon told me that I wouldn't have been able to detect that lump for five more years," she said. "And by then, I would have had many fewer options for therapy and surgery and a much different prognosis."
Guerriero said she is sharing her story in hopes of encouraging other women to get their routine mammograms.
The U.S. Preventive Services Task Force recommends all women get regular mammograms, a type of imaging, every two years to screen for breast cancer starting at age 40 until age 74. People with a family history of breast cancer should discuss with their clinician if they should be screened at an earlier age.
Breast cancer in women under age 50 is considered rare, but cases in younger women are becoming more common, with diagnoses rising at about 1.4% per year in the U.S., according to the Breast Cancer Research Foundation. Breast cancer is currently the leading cause of cancer deaths in U.S. women aged 20 to 49 years old.
Across all ages, breast cancer is the second-most frequently diagnosed cancer among women in the U.S., with more than 320,000 new invasive cases expected each year, according to the American Cancer Society.
Guerriero said her cancer diagnosis came decades after her grandmother's breast cancer diagnosis, which she said sparked her medical career.
"One of my earliest memories is my grandmother being diagnosed with breast cancer," she said. "As a young child, I remember wondering why some patients could be cured of cancer and some were not."
The research lab Guerriero leads at Brigham and Women's Hospital is focused on improving how patients with breast cancer respond to immunotherapy treatments.
"Our goal is to develop new therapeutic strategies for the treatment of breast cancer," she said, adding, "It's incredible how a breast cancer diagnosis can really motivate and fuel myself and my lab to work harder and faster to find new ways to treat breast cancer patients."