Tailored drugs needed to fight ‘very different’ breast cancer

"Because lobular carcinomas account for only 10 to 15 percent of breast cancers, while ductal carcinomas make up nearly 80 percent, lobular carcinomas are a less attractive option for laboratory study," says Matthew Sikora. "However, 30,000 women in the US are diagnosed with lobular carcinoma every year, so there is a great need for further study of this disease." (Credit: Pasha C/Flickr)

The second-most common type of breast cancer is a very different disease than the most common and appears to be a good candidate for a personalized approach to treatment, new research shows.

Invasive lobular carcinoma, which is characterized by a unique growth pattern in breast tissue that fails to form a lump, has distinct genetic markers that indicate there may be benefits from drug therapies beyond those typically prescribed for the more common invasive ductal carcinoma.

Patients with invasive lobular carcinoma are typically treated through surgical removal of the cancer, followed by chemotherapy or hormone therapy or both. The hormone therapy usually involves the estrogen-mimicking drug tamoxifen or estrogen-lowering aromatase inhibitors—the same drugs often used to treat patients with invasive ductal carcinoma.

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“However, recent analyses have shown that a subset of patients with lobular carcinoma receive less benefit from adjuvant tamoxifen than patients with ductal carcinoma,” says senior author Steffi Oesterreich, professor at the University of Pittsburgh Cancer Institute.

“Our study, the largest of its kind, indicates an issue with the estrogen receptors inside lobular carcinoma cells and points to a potential target for drug therapy in future clinical trials, which we are developing.”

“In addition to its potential clinical implications, the study highlights the need for more and better models mimicking invasive lobular cancer that can be used for laboratory studies,” says Matthew Sikora, a postdoctoral associate and lead author of the study published in Cancer Research.

“Because lobular carcinomas account for only 10 to 15 percent of breast cancers, while ductal carcinomas make up nearly 80 percent, lobular carcinomas are a less attractive option for laboratory study,” he says. “However, 30,000 women in the US are diagnosed with lobular carcinoma every year, so there is a great need for further study of this disease.”

Researchers at the University of Utah contributed to the study, which was supported by the Breast Cancer Research Foundation, Noreen Fraser Foundation, Department of Defense Breast Cancer Research Program fellowship and Era of Hope Scholar Award, and Pennsylvania Department of Health.

Source: University of Pittsburgh