Doctors are sounding the alarm as a rare and deadly breast cancer is rising sharply across the U.S. Cases of invasive lobular carcinoma (ILC) are now growing three times faster than other breast cancers. Between 2012 and 2021, rates jumped nearly 3% each year — and even higher since 2016.

“This is a serious concern,” said researcher Angela Giaquinto of the American Cancer Society. “The sheer number of new diagnoses makes this cancer impossible to ignore.” ILC often grows in scattered patterns, not lumps, making it harder to detect with standard mammograms.

Experts say hormonal and lifestyle factors — not genetics — are driving the surge. Rising obesity, later pregnancies, and longer estrogen exposure all increase risk. Once ILC spreads, only about 12% of patients survive 10 years, compared with 20% for more common types.

Researchers urge women to stay alert and prioritize screenings. “Early detection saves lives,” said senior scientist Rebecca Siegel. The growing trend is a reminder: awareness and prevention remain women’s strongest defense.