Diagnostic Accuracy of 18 F-FES PET/CT for the Detection of Recurrent and Metastatic Breast Cancer.

Purpose: To evaluate the diagnostic value of 16α- 18 F-fluoro-17β-fluoroestradiol ( 18 F-FES) PET/CT for distant metastasis or recurrence in patients with estrogen receptor (ER)-positive breast cancer.

Methods: Patients with ER-positive breast cancer and suspected of de novo metastasis or recurrence were retrospectively identified from a prospective cohort enrolled for a postmarketing surveillance study of 18 F-FES at our institution. Per-patient diagnostic accuracy was assessed using pathology or 2 or more standard-of-care imaging procedures with a minimum of 6 months of follow-up as the reference standard. The per-region detection rate of 18 F-FES PET/CT was evaluated and compared with that of standard-of-care imaging.

Results: Of the 162 included patients, 104 and 58 were suspected to have recurrence or de novo metastasis, respectively. The overall sensitivity and specificity of 18 F-FES PET/CT were 95% (95% confidence interval [CI], 89%-98%) and 89% (95% CI, 76%-96%), respectively. When stratified according to clinical settings, the sensitivity and specificity were 95% (95% CI, 88%-99%) and 96% (95% CI, 78%-100%), respectively, for detecting recurrence, and 94% (95% CI, 81%-99%) and 82% (95% CI, 60%-95%) for detecting distant metastasis. In region-based analysis, the overall detection rate of 18 F-FES PET/CT was significantly higher than that of standard-of-care imaging (92% [95% CI, 89%-94%] vs 83% [95% CI, 79%-87%], P < 0.001).

Conclusions: 18 F-FES PET/CT showed excellent diagnostic performance in patients with ER-positive breast cancer suspected of de novo metastasis or recurrence.