Use of Specialized PET/CT to Assess Estrogen Receptor Status in Recurrent or Metastatic Breast Cancer
In a Korean study reported in The Lancet Oncology, Chae et al found that 16α-[18F]fluoro-17β-oestradiol (18F-FES) positron-emission tomography/computed tomography (PET/CT) may permit accurate reevaluation of estrogen receptor status in recurrent or metastatic breast cancer when repeat biopsy is not feasible.
The prospective cohort study involved 85 evaluable patients treated at the Asan Medical Center, Seoul, between November 2013 and November 2016 who had first recurrence of breast cancer or metastatic disease at presentation. The primary objective of the study was to show the agreement between qualitative 18F-FES PET/CT interpretation and results of estrogen receptor expression testing on immunohistochemical assay. Patients underwent whole-body 18F-FES PET/CT, with 18F-FES uptake above background intensity interpreted as positive.
Positive and Negative Status Agreement
Among the 85 patients included in the efficacy analysis, 47 (55%) had estrogen receptor–positive disease and 38 (45%) had estrogen receptor–negative disease. Positive status agreement between the 18F-FES PET/CT results and estrogen receptor status by immunohistochemical assay was 76.6%, and negative status agreement was 100.0%. Patients who were estrogen receptor–positive and had positive 18F-FES PET/CT results were more likely to have progesterone receptor–positive expression (23 [68%] of 34 patients) than those who were estrogen receptor–-positive and had negative 18F-FES PET/CT results (0 of 11 patients; P < .0001).
The most common adverse event was procedural pain in 10% of patients injected with 18F-FES. No drug-related adverse events were observed except injection site pain in one patient (1%), and no serious adverse events were observed.
The investigators concluded, “The high negative percent agreement between 18F-FES PET/CT and estrogen receptor status by immunohistochemical assay in this cohort suggests that positive 18F-FES uptake by recurrent or metastatic estrogen receptor–positive breast cancer lesions could be an alternative to estrogen receptor assays in this setting. Staging assessment should include 18F-FES PET/CT when retesting estrogen receptor status is not feasible.”
Dae Hyuk Moon, MD, of Asan Medical Center, University of Ulsan College of Medicine, Seoul, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the Asan Institute for Life Sciences, Ministry of Health and Welfare, South Korea. The study authors' full disclosures can be found at thelancet.com.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
