FDA-approved PET imaging agent predicts breast cancer patients’ response to new treatment
Positron emission tomography imaging can predict how patients with hormonal therapy-resistant breast cancer may respond to a new type of treatment, according to research published in the February issue of the Journal of Nuclear Medicine.
Endocrine therapy is the top choice for the nearly two-thirds of breast cancer patients diagnosed as ER-positive, HER2-negative, oncology experts explained in the study.
If the cancer advances beyond such treatment, however, PET imaging with the radiotracer 18F-fluoroestradiol can help clinicians determine if additional therapy with targeted agents or chemotherapy may be needed to fight the disease, Hannah M. Linden, MD, a breast medical oncologist at the University of Washington in Seattle’s Cancer Research Center, explained.
“In some ER-positive breast cancer patients, cancer progression can be a result of a gradual resistance to endocrine therapy,” Linden added in a statement. “Histone daecetylase inhibitors (HDACIs) have been proposed as a mechanism to reverse endocrine resistance, and clinical studies have shown promising results when combining endocrine therapy with HDACIs to restore endocrine sensitivity.”
Looking to further understand this therapy, the group performed 18F-FDG PET imaging with 18F-fluoroestradiol in patients on a heavy dose of an HDACI known as vorinostat, along with another type of endocrine therapy. Patients received a baseline scan, and subsequent imaging during week two and eight of the study. Eight participants were treated with vorinostat and then an aromatase inhibitor, while 15 received both at the same time.
The researchers reported that eight individuals were stable at eight weeks, and six of those patients were OK for more than six months. Additionally, higher 18F-fluoroestradiol uptake at baseline was associated with longer progression-free survival.
“We test ER expression in a metastatic biopsy once at the beginning of the patient’s journey,” Linden added, noting all treatment decisions along the way, such as chemo and endocrine therapy, are based on that single measurement.
“Since we know that ER expression can fluctuate, imaging with 18F-fluoroestradiol at various time points could help clinicians predict response to endocrine therapy and select optimal treatment in the future,” the cancer specialist remarked.
Matt joined Chicago’s TriMed team in 2018 covering all areas of health imaging after two years reporting on the hospital field. He holds a bachelor’s in English from UIC, and enjoys a good cup of coffee and an interesting documentary.