Estrogen receptor-positive (ER+) breast cancer is the most common type of breast cancer diagnosed today. ER+ breast cancer presents a unique set of challenges for determining optimal treatment approaches. There is recognition that not all ER+ breast cancers benefit from chemotherapy, and there may be a subset of ER+ breast cancers that can be spared cytotoxic drugs and treated effectively using endocrine therapies alone. In the neoadjuvant treatment setting, imaging plays a critical role in non-invasively assessing the response of the intact primary tumor to targeted systemic therapies. Imaging evaluation of the primary tumor during treatment can provide important prognostic and predictive information.

Dedicated breast positron emission tomography (dbPET) is an emerging technology in radiology. Db-PET imaging with [F-18] fluoroestradiol (FES) as a tracer presents a new opportunity to develop an imaging marker for ER+ breast cancer. With the high overall sensitivity and specificity to ER, this new breast imaging tool may holistically inform the whole tumor ER functionality and provide valuable information to guide therapy selection.

Researchers with the UC San Francisco Department of Radiology and Biomedical Imaging set out to evaluate FES-dbPET technology for enabling a more precise characterization of ER+ primary breast tumor and its response to neoadjuvant treatment. To perform this study, researchers used a small cohort of six patients with >90 percent ER+ and HER2 breast cancers. They imaged using dbPET and breast MRI. They concluded that FES-dbPET has a high potential for clinical utility, especially in measuring response to neoadjuvant endocrine treatment. The results were published in npj Breast Cancer, part of the Nature Partner Journals series, dedicated to publishing the finest research on breast cancer research and treatment.

Ella Jones, PhD, research specialist, was the lead author on this study. Co-authors from UCSF Radiology included Kimberly Ray, MD; Wen Li, PhD; Ben Franc, MD; Youngho Seo, PhD; Miguel Hernandez Pampaloni, MD; Bonnie Joe, MD, PhD and Nola Hylton, PhD. Other authors from UCSF include Amy Jo Chien, MD; Rita Mukhtar, MD and Laura Esserman, MD, all of the UCSF Helen Diller Family Comprehensive Cancer Center.