PET Technique Useful in Challenging Breast Cancer Cases

Whole-body positron emission tomography with the PET tracer 16a-18F-fluoro-17b-estradiol  (18F-FES) can provide valuable information for patients with estrogen receptor-positive breast cancer if standard work-ups are inconclusive, according to an article published in the February issue of the Journal of Nuclear Medicine.

Estrogen receptor activity occurs in approximately 75 percent of breast tumors at time of diagnosis. Expression can also indicate a patient’s potential response to treatment. However, for a variety of reasons, including not being able to repeatedly biopsy difficult-to-reach tumors, determining ER activity is not always possible.

Inconclusive results from conventional methods make it difficult for physicians to determine treatment, specifically whether to administer anti-hormonal therapy. To address this issue, researchers in the Netherlands evaluated the use of 18F-FES in 33 women with a history of ER-positive breast cancer, each of whom had an inconclusive complete standard work-up.

Results showed that the 18F-FES PET was particularly sensitive for detecting bone metastases. 18F-FES improved the diagnostic understanding in 88 percent of the patients and prompted physicians to change treatment in 48 percent. The procedure was not effective for detecting lesions in the liver, as the sensitivity for liver metastases was poor.

“The specificity of the FES-tracer or estrogen receptors makes this technique ideal for aiding physicians working with clinical dilemmas in estrogen-receptor positive breast cancer patients and could potentially lead to faster diagnosis and earlier implementation of appropriate treatments,” said one of the authors, Geke Hospers, MD, PhD, professor of medical oncology, University Medical Center Groningen, the Netherlands.