Comparison of diagnostic sensitivity of [ 18 F]fluoroestradiol and [ 18 F]fluorodeoxyglucose positron emission tomography/computed tomography for breast cancer recurrence in patients with a history of estrogen receptor-positive primary breast cancer.

BACKGROUND: To compare the diagnostic sensitivity of [18 F]fluoroestradiol ([18 F]FES) and [18 F]fluorodeoxyglucose ([18 F]FDG) positron emission tomography/computed tomography (PET/CT) for breast cancer recurrence in patients with estrogen receptor (ER)-positive primary breast cancer.

METHODS: Our database of consecutive patients enrolled in a previous prospective cohort study to assess [18 F]FES PET/CT was reviewed to identify eligible patients who had ER-positive primary breast cancer with suspected first recurrence at presentation and who underwent [18 F]FDG PET/CT. The sensitivity of qualitative [18 F]FES and [18 F]FDG PET/CT interpretations was assessed, comparing them with histological diagnoses.

RESULTS: Of the 46 enrolled patients, 45 were confirmed as having recurrent breast cancer, while one was diagnosed with chronic granulomatous inflammation. Forty (89%) patients were ER-positive, four (9%) were ER-negative, and one (2%) patient did not undergo an ER assay. The sensitivity of [18 F]FES PET/CT was 71.1% (32/45, 95% CI, 55.7-83.6), while that of [18 F]FDG PET/CT was 80.0% (36/45, 95% CI, 65.4-90.4) with a threshold of positive interpretation, and 93.3% (42/45, 95% CI, 81.7-98.6) when a threshold of equivocal was used. There was no significant difference in sensitivity between [18 F]FES and [18 F]FDG PET/CT (P = 0.48) with a threshold of positive [18 F]FDG uptake, but the sensitivity of [18 F]FDG was significantly higher than [18 F]FES (P = 0.013) with a threshold of equivocal [18 F]FDG uptake. One patient with a benign lesion showed negative [18 F]FES but positive [18 F]FDG uptake.

CONCLUSIONS: The restaging of patients who had ER-positive primary breast cancer and present with recurrent disease may include [18 F]FES PET/CT as an initial test when standard imaging studies are equivocal or suspicious.