RT Journal Article SR Electronic T1 18F-FDG PET/CT Findings and Circulating Tumor Cell Counts in the Monitoring of Systemic Therapies for Bone Metastases from Breast Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1213 OP 1218 DO 10.2967/jnumed.110.076455 VO 51 IS 8 A1 Ugo De Giorgi A1 Michal Mego A1 Eric M. Rohren A1 Ping Liu A1 Beverly C. Handy A1 James M. Reuben A1 Homer A. Macapinlac A1 Gabriel N. Hortobagyi A1 Massimo Cristofanilli A1 Naoto T. Ueno YR 2010 UL http://jnm.snmjournals.org/content/51/8/1213.abstract AB Our objective was to compare the predictive significance of 18F-FDG PET/CT findings and circulating tumor cell (CTC) count in patients with bone metastases from breast cancer treated with standard systemic therapy. Methods: Breast cancer patients with progressive bone-only metastatic disease without visceral metastases starting a new line of systemic therapy underwent 18F-FDG PET/CT and had CTC counts determined before and during treatment. Disease status was reassessed by CTC count (≥5 vs. <5 CTC/7.5 mL of blood) and 18F-FDG PET/CT approximately 2–4 mo after initiation of the new systemic therapy. Results: CTC counts at follow-up agreed with the 18F-FDG PET/CT assessment in 43 (78%) of the 55 evaluable patients. Of the 12 patients with discordant CTC and 18F-FDG PET/CT results, 8 (66%) had ≥5 CTCs, with no evidence of progressive disease at the time of the 18F-FDG PET/CT study, whereas 4 (33%) had <5 CTCs, with evidence of progressive disease by 18F-FDG PET/CT. 18F-FDG PET/CT findings and follow-up CTC counts were found to be significantly associated with both progression-free survival (P = 0.02 and P < 0.0001, respectively) and overall survival (P = 0.02 and P = 0.01, respectively). In multivariate analysis, the 18F-FDG PET/CT assessment remained as the only predictive factor for progression-free survival (P < 0.0001), whereas estrogen receptor status was the only predictive factor for overall survival (P = 0.01). Conclusion: 18F-FDG PET/CT is a useful tool for therapeutic monitoring in patients with bone metastases from breast cancer. Prospective studies are needed to define the role of 18F-FDG PET/CT and CTC in the setting of response discordance to establish bone-dominant disease as a tumor-response measurable disease.