Why Are More Young Women Being Diagnosed With Breast Cancer?

Siobhan Donovan was a runner who ate her vegetables, didn’t smoke and drank alcohol only socially.She had no family history of cancer.

So when she experienced some swelling in her breast near the end of what she called “a textbook-easy pregnancy” with her third child, she and her doctors expected nothing serious.They were wrong.Ms.

Donovan, who was 33 at the time, had metastatic breast cancer that had spread to her bones.“I was really just in shock,” she said, adding that back then she didn’t even know the meaning of the word “metastasis.”Like Ms.Donovan, a growing number of younger women are being diagnosed with breast cancer, according to new estimates released Thursday by the American Cancer Society.

Between 2012 and 2021, the incidence rate of breast cancer overall increased by about 1 percent each year, while the incidence rate among women under age 50 increased by about 1.4 percent each year.Patients with “young-onset breast cancer” — which clinicians typically define as diagnosed before the age of 40 — are more likely than older patients to have aggressive forms of the disease, said Dr.

Ann Partridge, interim chair of medical oncology at the Dana-Farber Cancer Institute in Boston.The increase in breast cancer rates among younger patients is occurring as the incidence of other early-onset cancers — including colorectal, gastric, kidney and liver cancer — is also on the rise, though cancer among patients under 50 is still relatively rare overall, Dr.Partridge said.In 2024, there were just under 51,000 new invasive breast cancer cases among women under 50, compared with about 260,000 cases among women 50 years of age and older, according to American Cancer Society statistics.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access.

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