Purpose. We compared the clinical value of 16a-18F-fluoro-17b-estradiol ( 18 F-FES) positron emission tomography (PET)/ computed tomography (CT) and 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/CT and investigated whether and how 18 F-FES PET/CT affects the implemented management of newly diagnosed estrogen receptor positive breast cancer patients. Materials and Methods. We retrospectively analyzed 19 female patients newly diagnosed with immunohistochemistry-confirmed estrogen receptor (ER)-positive breast cancer who underwent 18 F-FES and 18 F-FDG PET/CT within 1 week in our center. The sensitivity of 18 F-FES and 18 F-FDG in diagnosed lesions were compared. To investigate the definite clinical impact of 18 F-FES on managing patients with newly diagnosed ER positive breast cancer, we designed two kinds of questionnaires. Referring physicians completed the first questionnaire based on the 18 F-FDG report to propose the treatment regime, and the second was completed immediately after reviewing the imaging report of 18 F-FES to indicate intended management changes. Results. In total, 238 lesions were analyzed in 19 patients with newly diagnosed ER-positive breast cancer. Lesion detection was achieved in 216 sites with 18 F-FES PET and in 197 sites with 18 F-FDG PET/CT. These results corresponded to sensitivities of 90.8% for 18 F-FES versus 82.8% for 18 F-FDG PET/CT in diagnosed lesions. Thirty-five physicians were given the questionnaires referring to the treatment strategy, with 27 of them completing both questionnaires. The application of 18 F-FES in addition to 18 F-FDG PET/CT changed the management in 26.3% of the 19 patients with newly diagnosed ER-positive breast cancer. Conclusion. Performing 18 F-FES PET/CT in newly diagnosed ER-positive breast cancer patients increases the value of diagnosis equivocal lesions and treatment management compared with 18 F-FDG PET/CT. The Oncologist 2019;24:e1277-e1285 Implications for Practice: This study investigated whether 16a-18F-fluoro-17b-estradiol ( 18 F-FES) positron emission tomography (PET)/computed tomography (CT) affects the clinical management of patients with newly diagnosed estrogen receptor (ER)-positive breast cancer. Physicians completing two questionnaires comparing the clinical impact of 18F-FES and 18F-FDG on individual management plans in patients with newly diagnosed ER-positive breast cancer confirmed that 18F-FES scans led to change in management in 26.3% of the 19 patients with newly diagnosed ER positive breast cancer. This retrospective study indicates the potential impact of 18F-FES PET/CT on intended management of patients with newly diagnosed estrogen receptor positive breast cancer in comparison to 18F-fluoro-2-deoxy-D-glucose PET/CT.

BackgroundEverolimus significantly improves progression-free survival (PFS) and has been approved to use in aromatase inhibitor pretreated patients with hormone receptor positive advanced breast cancer. Metformin has been shown to inhibit mTOR pathway, with more favorable safety profile, leading to this hypothesis-generating trial to assess whether metformin enhances the efficacy of aromatase inhibitors.Methods60 postmenopausal women with hormone receptor positive locally advanced or metastatic breast cancer were randomly assigned 1:1 to aromatase inhibitor (exemestane 25mg/d or letrozole 2.5mg/d depending on the most recent treatment) plus metformin (0.5g bid, orally) or placebo. The primary endpoint was PFS, and secondary endpoints were objective response rate, clinical benefit rate, overall survival and safety.ResultsMedian PFS was 4.7 months in the combination group and 6.0 months in the control group (hazard ratio, 1.2; 95% confidence interval [CI], 0.7 to 2.1; P =0.48). ORR was 6.7% in the combination group and 0% in the control group (odds ratio for ORR not available; P =0.99), and CBR was 33.3% and 50.0%, respectively (OR for CBR 0.5; 95% CI, 0.2 to 1.4; P=0.15). No significant difference in overall survival was observed between the combination and control groups (median OS, 30.9 vs. 32.4 months; P = 0.81). Subgroup analyses didn't find any specific population favoring the combination treatment. No substantial difference in incidence or severity of adverse events was seen between the two treatment groups.ConclusionThis randomized phase II clinical trial failed to show an improved efficacy with the addition of metformin to endocrine therapy, although with excellent tolerability.

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The present explorative study was initiated to evaluate the clinical value of 18F-FES PET/CT in monitoring the change of estrogen receptor (ER) expression and potential predictive value in metastatic breast cancer patients. Twenty-two pathology-confirmed breast cancer patients were prospectively enrolled and randomly divided into two groups (T: docetaxel, n = 14 and TF: docetaxel + fulvestrant, n = 8). The percentage of patients without disease progression after 12 months (PFS > 12 months) was 62.5% in group TF compared with 21.4% in group T (P = 0.08). According to 18F-FES PET/CT scans, the SUVmax (maximum standard uptake value) of all the metastatic lesions decreased in group TF after 2 cycles of treatment (6 weeks ± 3 days). However, 6 of 9 patients in group T had at least one lesion with higher post-treatment SUVmax. There was a significant difference in the reduction of ER expression between these two groups (P = 0.028). In group TF, the patients with PFS > 12 months had significantly greater SUVmax changes of 18F-FES than those with PFS < 12 months (PFS > 12 months: 91.0 ± 12.0% versus PFS < 12 months: 20.7 ± 16.2%; t = −4.64, P = 0.01). Our preliminary study showed that 18F-FES PET/CT, as a noninvasive method to monitor ER expression, could be utilized to predict prognosis based on changes in SUVmax.