In the US, cases of invasive lobular breast cancer (ILC)— a form of breast cancer that begins in the milk-producing glands—are rising faster than other breast cancer types, a new American Cancer Society report finds.
Between 2012 and 2021, ILC cases increased by 2.8% per year, compared with 0.8% per year for breast cancer overall. In 2025, invasive breast cancer will be diagnosed in an estimated 316,950 women and 2,800 men in the US; about 33,600 women are expected to have ILC—roughly 1 in 10 new breast cancers in women.
Lobular breast cancer is most often found in older women, with more than half of new cases diagnosed at age 65 or older. Still, rates are increasing among both younger and older women—a pattern not seen with other types of breast cancer.
The highest incidence is among White women (14.7 cases per 100,000), followed by Black women (11 per 100,000), though the steepest rise has been among Asian American and Pacific Islander women, whose rates increased by 4.4% per year during the past decade.
Lobular breast cancers are overwhelmingly hormone-receptor positive (HR+) and HER2-negative: 90 percent of ILCs are HR+/HER2–, compared with 69 percent of ductal carcinomas. Only 5 percent of lobular cancers are HER2-positive, and fewer than 2 percent are triple-negative (HR–/HER2–).
This contrasts with ductal cancers, where about 12 percent are triple-negative and 15 percent are HER2-positive.
Researchers believe this rise may be connected to changes in hormonal and reproductive factors over time, such as later age at first childbirth and increasing body weight.
The study does not provide mortality by histology (i.e., lobular vs. ductal) because death records don’t include this information. However, 10-year relative survival is slightly better for ILC than for ductal cancers through about 7 years after diagnosis, then is comparable to ductal. By stage at diagnosis, ILC has higher 10-year survival when it is localized, but lower survival for regional (76.4% vs. 78.2%) and distant (metastatic) disease (12.1% vs. 19.6%) compared with ductal breast cancers.
While early-stage lobular breast cancers generally have good outcomes, the distinct biology and growth pattern of this subtype can make detection and treatment more challenging.
Understanding and tracking these changing trends are important—not only to improve care for those affected by lobular breast cancer, but also to advance NBCC’s overarching mission to end all breast cancer through research, advocacy, and informed public policy.
