A little-known type of breast cancer is on the rise among American women, highlighting the need for us to pay closer attention to it.
Approximately 33,600 women will be diagnosed with lobular breast cancer or invasive lobular carcinoma (ILC) this year, according to new projections from the American Cancer Society (ACS).
The report found that the incidence of ILCs, which originate in milk-producing glands in the breast, increased more steeply (2.8% per year) from 2012 to 2021 than all other breast cancers combined (0.8%).
“Lobular breast cancer accounts for just over 10% of all breast cancers, but the number of new diagnoses each year makes it important to understand this disease,” Angela Giaquinto, report author and associate scientist at ACS, said in a statement.
“Additionally, survival rates beyond 7 years for ILC are significantly lower than for the most common type of breast cancer (invasive ductal carcinoma (IDC)), highlighting the greatest urgency for prevention and early detection strategies targeting this type.”
The authors emphasize that this is necessary to increase the likelihood of better patient outcomes.
“Despite the fact that most ILCs are hormone-positive (96% vs. 80% of ductal carcinomas), it is unclear why ILCs increase more steeply than other breast cancers because information about this subtype is lacking,” Giaquinto said. newsweek.
“We know that hormone-positive breast cancer is on the rise due to risk factors such as increased excess weight, increased alcohol consumption in certain age groups, decreased physical activity, and changing reproductive patterns (such as later age at first birth, fewer children, and no children).”
In research and clinical trials, ILCs are typically combined with the more common IDCs, which, according to the study authors, may hide many of their unique key appearance and growth characteristics.
“ILC has unique characteristics that may contribute to delayed detection, resistance to treatment, and poor prognosis for advanced disease,” the study authors wrote in the paper.
“Distinguishing between ductal carcinoma in situ and ILC in research and clinical trials can help identify risk factors, promote treatment efficacy, and lead to a better understanding of mechanisms of metastasis, thereby improving outcomes for the growing number of affected women.”
Mirroring trends seen in other breast cancers, the US report also found the steepest increase in ILC incidence among Asian American and Pacific Islander women, increasing by 4.4% per year from 2012 to 2021.
Overall, white women have the highest incidence of ILC and black women have the second highest incidence.
Survival rates for women with ILC are slightly higher than those for ductal breast cancer and local-stage disease in the first 7 years after diagnosis, whereas they are lower for both localized and distant-stage disease in the 10 years after diagnosis.
“Invasive lobular breast cancer is very understudied because its short-term prognosis is very good. However, after 10 years, women with metastatic disease have about half the chance of survival as patients with ductal cancer, possibly due to its unique spread and resistance to treatment,” Rebecca Siegel, ACS’ chief scientific officer, said in a statement.
“Our study highlights the need for much more information about lobular cancer across the board, from genetic studies to clinical trial data, so we can improve outcomes for the growing number of women with this cancer.”
Giaquinto said women should also be aware of breast cancer symptoms other than lumps, such as nipple inversion, thickening of the breast skin, and depressions and swellings common in lobular breast cancer, and discuss any ongoing changes with their doctors.
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Updated 10/09/25, 04:55 am ET: This article has been updated with additional information and comments from Angela Giaquinto.
reference
Giaquinto, An, Freedman, R. A., Newman, La, Jemal, A., & Siegel, Rl. (2025). lobular breast cancer statistics, cancer, 131(20).
