An increase in cases of lobular breast cancer or invasive lobular carcinoma (ILC) has been recorded in the United States. Its share now accounts for slightly more than 10% of all breast cancer cases, researchers write in the journal PLOS.

This year, approximately 33,600 women in the US may be diagnosed with ILC.

From 2012 to 2021, the incidence of this breast cancer increased by about 2.8% annually, compared to about 0.8% per year for all other types of breast cancer.

The respective study also found that among women with ILC, the survival rate 10 years after diagnosis is slightly higher at localized stages than among those diagnosed with the more common type — ductal carcinoma. However, at regional — more advanced — and especially early metastatic stages, the survival rate for ILC is considerably lower.

In addition, the rise in cases of ILC is particularly pronounced among Asian American and Pacific Islander women, with an annual increase of 4.4%. Among racial/ethnic groups, white women have the highest incidence — about 14.7 per 100,000 — of ILC, followed by Black women — about 11 per 100,000.

Researchers emphasize that ILC is often grouped together with other forms of breast cancer in studies and clinical trials, and this makes it difficult to account for its specific characteristics — such as patterns of growth and spread, diagnosis, and response to treatment.

Due to its atypical tumor growth, which appears as a linear or loose diffuse network, this cancer can remain undetected for longer than ductal carcinoma, worsening the prognosis at advanced stages.

The authors of the aforesaid study call for increased efforts in the early detection and research of this cancer subtype — both to understand its genetic basis and to develop targeted therapies.